conjugated shape - persistent 
 macrocycles and , in particular , arylene 
 ethynylene macrocycles ( aems ) have received 
 much attention in recent years 
 because advances in synthetic techniques have made them more accessible , 
 and they have potential in many applications . aems are relatively 
 thermally , photolytically , and oxidatively stable ; they often have strong uv absorptions and are often highly 
 fluorescent . additionally , these macrocycles have been of interest because their 
 high polarizability makes them desirable as second - order nonlinear 
 optical materials and as materials for 
 organic semiconductors and devices . their unique two - dimensional structure could 
 potentially allow these materials to circumvent the trade - off between 
 efficiency and transparency observed in linear systems , and c3-symmetric systems can be derivatized to give 
 noncentrosymmetric materials . planar aems have been shown to aggregate 
 in solution , in the liquid crystalline 
 phase , and in the solid phase through weak van der waals interactions . aems 
 can aggregate into columnar mesophases as well as vesicles and have the potential to act as model systems 
 for organic nanotubes . arylene 
 ethynylene macrocycles are synthetically accessible either 
 by statistical cyclization of a single aryl halide ethynyl monomer or by the cyclization of a linear oligomer via a palladium catalyzed 
 cross coupling , in either case at low 
 concentrations . this latter approach requires a linear , stepwise , 
 and often tedious synthesis of the linear oligomer but usually gives 
 a single discrete macrocycle as the sole product . alternatively , the 
 former methodology employs more synthetically accessible precursors 
 but often yields various cyclic and linear oligomers unless specific macrocycle ring sizes are excluded by ring 
 strain or steric interactions on neighboring monomer units . more recently , alkyne metathesis has proven 
 to be an efficient synthetic method to prepare the arylene ethynylene 
 scaffold . metathesis allows the formation 
 of the thermodynamically most favored product(s ) but may not offer 
 the functional group tolerance of the palladium - catalyzed protocols . derivatization of the monomers should allow the formation of electron - rich 
 and/or electron - poor ring systems and thus the tuning of their physical 
 properties . the incorporation of side chains is often crucial to allow 
 the solubility of the highly rigid macrocycles . despite the 
 recent attention given arylene ethynylene macrocycles , the incorporation of biphenyl and terphenyl moieties is rare , and 
 such macrocycles have not been fully explored . the few reported examples 
 of biphenyl or teraryl units include bipyridyl , m - terphenyl , m - terpyridinyl , and 
 11,12-dihydroindolo[2,3-a]carbazole ( nominal p - terphenylenes ) and tetram - phenylene subunits but no 
 simple biphenyl or p - terphenylene containing macrocycles 
 have been reported . the presence of such biphenyl units disrupts the 
 fully planar geometry of the macrocycle and would therefore be expected 
 to attenuate any aggregation via stacking of the planar rings . the 
 deviation from planarity also would affect the conjugation around 
 the macrocycle , and change their electronic properties in comparison 
 to their fully planar analogs . more significantly , the title c3 macrocycles 
 offer the possibility to synthesize short segments of single - walled 
 carbon nanotubes . ethynylene units in shape - persistent macrocycles 
 are usually used as rigid spacers that prevent diaryl steric interactions . however , alkynes are also reactive moieties , and if the alkynes in 
 the title macrocycles can be incorporated into ortho - substituted aromatic rings via cycloaddition reactions with cyclopentadienone 
 synthons , the vertices of the triangular macrocycles could be folded 
 out of the plane to form the walls of the nanotube segment . the phenylene rings in such a cycloaddition 
 product are geometrically disposed to produce a fully fused nanotube 
 segment upon oxidative cyclodehydrogenation ( figure 2 ) . this synthetic path toward carbon nanotube segments relies 
 on the title macrocycles as relatively strain - free templates that 
 are elaborated with additional phenyl rings in a stepwise increase 
 of strain until the fused tube is achieved . alternatively , macrocycles 
 containing cyclopentadienone moieties could be constructed and undergo 
 cycloadditions with diarylalkynes to give similar cyclooligophenylenes . a similar strain strategy pioneered by 
 bertozzi and jasti converts a more highly 
 curved precursor containing 
 sp centers to the all - sp nanotube segment . jasti , itami , and others have used this route to 
 prepare a variety of [ n]cycloparaphenylenes , and 
 jasti and mullen have recently prepared [ n]cycloparaphenylenes that 
 could in principle give belts of longer length upon oxidative cyclodehydrogenation 
 of pendant phenyl substituents . bodwell has also prepared highly curved nanotube segments by incorporating 
 polycyclic arenes in cyclophanes . scott has proposed a slightly different 
 approach that uses bowl - shaped templates upon which the nanotube can 
 be grown . to further our synthetic proposal , 
 the synthesis of c3-symmetric biphenyl 
 and terphenyl arylene ethynylene macrocycles and their alkyl derivatives , 
 along with their photophysical properties , are described below . as discussed above , 
 the construction 
 of cyclooligomers is usually achieved by one of two means : a statistical 
 coupling of simple monomer units or a cyclization of a linear oligomer 
 of appropriate length . the former method involves a shorter synthetic 
 route and was the first one attempted for the construction of the c3-symmetric macrocycles 1a , 1b , 2a , and 2b . since both synthetic 
 approaches require monomers 3a , 3b , 4a , and 4b , they were prepared first . the diethyltriazene 
 and triisopropylsilyl groups on the termini of 3 and 4 are protecting groups that can be removed under orthogonal 
 reaction conditions to give the aryl iodide or terminal alkyne , respectively . a statistical macrocyclization would require both groups to be deprotected 
 to give the ab monomer , while the synthesis of a linear trimer which 
 could be subsequently cyclized could be accomplished using a split - pool 
 strategy ( scheme 1 ) . triazene 5 was prepared 
 in 97% yield by diazotization of 4-iodoaniline followed by quenching 
 with diethylamine . boronation of 5 with 1.2 equiv of 
 bis(pinacalato)diboron , cl2pd(dppf ) , and dry koac in dmso 
 gave 6 in 74% yield . however , this boronation also produced 
 a significant quantity of biphenyl 7 which could only 
 be removed by recrystallization from 2-propanol . in an attempt to 
 minimize the formation of this undesired homodimer , a 3-fold excess 
 of bis(pinacalato)boron no homodimerization was observed , 
 but the excess diboron proved equally difficult to remove during purification . the most effective purification protocol involves recrystallization 
 from 2-propanol to remove the homodimer 7 followed by 
 column chromatography to remove the residual palladium and excess 
 diboron . alternatively , 6 was prepared by diethylamine 
 addition to the diazotized aminophenylboronic acid pinacol ester in 
 85% yield . this second protocol not only provided an overall higher 
 yield of the phenylene synthon 6 but also a high enough 
 purity after workup that the crude product could be used in further 
 reactions without further purification , in stark contrast to the first 
 protocol . alkyne coupling partner 8 was prepared in 99% 
 yield according to literature procedures from 1-bromo-2-iodobenzene 
 and triisopropylsilylacetylene . suzuki coupling of the boronate ester 6 and alkyne 8 was performed using cl2pd(dppf ) and k3po4 in dme to give the biphenyl 
 monomer 3a in 95% yield . it should be noted that other 
 palladium catalysts 
 ( notably pd(pph4)3 ) , bases , and solvents did 
 not give comparable yields . terphenyl monomer 4a was 
 prepared in 65% yield from triazene 3a by treatment with 
 iodomethane to give 9 followed by a suzuki coupling with 
 triazene 6 . despite the more reactive iodide and lack 
 of hindering ortho group in 9 compared 
 to 8 , the lower yield for the second suzuki coupling 
 was the result of competitive protiodeiodination to give 2-(triisopropylsilylethynyl)biphenyl . the terphenyl 
 triazene also undergoes photolytic decomposition , especially in the 
 presence of silica gel or florisil ; alumina was used in the chromatography 
 of all terphenyl triazenes described , and little such decomposition 
 was observed on this stationary phase . since the macrocycles 
 constructed from 3a and 4a were anticipated 
 to have low solubility , alkyl - substituted 
 analogues 3b and 4b were also prepared ( scheme 3 ) . octylaniline 10 was iodinated with 
 an ammonium dichloroiodate with high regiospecificity give iodoarene 11 , which was diazotized and quenched with diethylamine gave 
 triazene 12 . the sonogashira coupling of 12 with triisopropylsilylacetylene gave 13 , which was 
 then converted to iodoarene 14 in 86% yield over four 
 steps . as with the unsubstituted analogues , biphenyl monomer 3b was obtained by suzuki  miyaura coupling of 6 and 14 , and terphenyl monomer 4b was obtained 
 from 3b by deprotection of the triazene in 3b with methyl iodide to give iodoarene 15 ( in 94% yield ) 
 which was then coupled with another equivalent of 6 . initial attempts to couple 6 and 14 produced 
 very poor yields of 3b along with significant quantities 
 of ( 3-octylphenylethynyl)triisopropylsilane , the protiodeiodination 
 product of 14 . the concentration of reactants was increased 
 5-fold in an attempt to make the coupling more competitive with protiodeiodination , 
 and the yield of the desired biphenyl 3b was increased 
 to 82% . the careful exclusion of water , a potential source of protons , did not increase the yield of coupled product 3b appreciably . additionally , the yield of the suzuki coupling 
 to produce the terphenyl monomer 4b was 68% , lower than 
 that for 3b , presumably for the same reasons discussed 
 above for 3a . the 
 doubly deprotected 
 monomeric iodoalkynes 16a and 17a were obtained 
 by diethyltriazene removal in methyl iodide followed by fluoride deprotection 
 of the ethynyl protecting groups ( scheme 2 ) 
 in 88% and 71% yields over two steps , respectively . the instability 
 of terphenyl 17a required that this free alkyne be utilized 
 immediately after preparation and explains the lower yield of its 
 preparation in comparison to the biphenyl 16a . biphenyl 
 monomer 16a was subjected to sonogashira reaction conditions 
 using cl2pd(pph3)2 at low concentration 
 ( 18 mm ) for 10 days at room temperature to give a product mixture 
 containing a mixture of linear and cyclic oligomers . poor solubility 
 and similar polarities of the reaction products precluded chromatographic 
 separation or purification , but the presence of 1a was 
 evident by peaks in the h nmr ( figure 3 ) that matched those in pure samples of 1a obtained 
 by the alternate synthesis described below . stephens  castro coupling of terphenyl monomer 17a at 182 mm and sonogashira coupling at 155 mm with pd(pph3)2cl2 gave only an insoluble yellow 
 product , 
 which had an h nmr spectrum consistent with a mixture 
 of linear and cyclic oligomers . the sonogashira coupling of 17a was attempted again , using pd(pph3)4 and at lower concentration , 18 mm . after 12 days at room temperature , 
 this reaction yielded a solid that when washed repeatedly with methylene 
 chloride proved to be macrocycle 2a . the cyclic trimer 
 was isolated in 20% crude yield but could not be separated from an 
 impurity of unknown structure . similar protocols were used to 
 convert the alkyl - substituted monomers 3b and 4b to cyclooligomers . double deprotection 
 of 3b and 4b to give 16b and 17b proceeded as with the unsubstituted analogues in 68% and 
 98% yields over two steps , respectively . compound 16b was subjected to sonogashira coupling conditions at 28 mm ; four 
 fluorescent compounds were identified by tlc , but only two compounds 
 were isolated by five iterations of flash chromatography , the cyclic 
 trimer 1b in 36% yield , and the cyclic tetramer 1c in 24% . in an effort to improve the yield of the cyclooligomers , 
 the concentration was lowered to 1.5 mm in the sonogashira coupling 
 reaction of 17b . a 51% yield of the cyclic trimer 2b was recovered by column chromatography as well as cyclic 
 dimer 2c in 12% yield . the yield of the cyclic trimer 
 may also have been higher in the cyclooligomerization of 17b because of the use of pd(pph3)4 instead of 
 pdcl2(pph3)2 . the isolation of the 
 substituted macrocycles was greatly facilitated by their much higher 
 solubility , attributable to their long alkyl side chains . analytically pure 
 samples of 1a and 2a were obtained by constructing 
 each through a linear , stepwise approach ( schemes 4 and 5 , respectively ) . this split pool 
 approach began with the removal of the diethyltriazene of 3a to give 18a in 98% yield and the removal of the ethynyl 
 protecting group of 3a using tbaf to yield 19a in 90% yield ( scheme 3 ) . sonogashira coupling 
 of fragments 18a and 19a gave the protected 
 dimer 20a in 75% yield . unmasking the aryl iodide by 
 removal of the diethyltriazene was followed by a second coupling with 
 fragment 19a , which led to the linear trimer 22a in 67% yield over the two steps . deprotection 
 of 23a with tbaf gave an iodoarylethyne which was immediately 
 subjected to sonogashira coupling conditions without purification . the cyclization was performed by slowly adding a solution of the linear 
 trimer iodoarylethyne with a syringe pump to a solution of the catalysts 
 in triethylamine . the final and highest concentration of the linear 
 trimer was 3.7 mm , and after the addition was complete , the reaction 
 was stirred for another 12 h before workup . a split - pool approach to the terphenyl macrocycle 2a also occurred in a similar sequence , but the additional p - phenylene unit within the monomer unit contributed to 
 solubility problems ( scheme 4 ) . both deprotections 
 of 3b proceeded in 91% yield to give the iodide 18b and terminal alkyne 19b , which were coupled 
 under sonogashira conditions to give dimer 20b in 76% 
 yield . a significant quantity of unreacted 18b was also 
 recovered , along with a similar amount of a third organic product 
 which is presumed to be the hay coupled dialkyne arising from dimerization 
 of 19b . conversion of the triazene to the iodide 21b and sonogashira coupling with another 1.3 equiv of 19b gave the trimer 22b in 52% combined yield . the lower yield compared to the biphenyl system can be attributed 
 to losses during chromatography of the sparingly soluble synthons , 
 and the larger excess of the terminal alkyne was utilized to minimize 
 yield loss due to hay coupling . removal of 
 the tips group gave the sparingly soluble iodoarylethyne linear trimer ; 
 the loss of the relatively small alkyl groups in the tips group significantly 
 lowered its solubility , and its subsequent cyclization was carried 
 out without further chromatographic purification or complete characterization . as with the biphenyl trimer , the cyclization was carried out under 
 high dilution sonogashira conditions ( 2.1 mm ) achieved using a syringe 
 pump . the product mixture was purified by removing the solvent and 
 centrifugation of the residue slurried with dichloromethane . the insoluble 
 organic products floated on the chlorinated solvent while the inorganic 
 catalysts and byproducts thereof formed a solid pellet . the 
 formation of both linear and cyclic oligomers of various sizes during 
 cyclooligomerization is not unexpected and has been shown to occur 
 in various systems under a wide array of reaction conditions . in some of these reports , the cyclotrimeric 
 and cyclotetrameric products isolated from o - iodoethynylenebenzene 
 precursors were relatively unstrained . other studies have reported the production of strained cyclic dimeric 
 species along with unstrained cyclotrimers and cyclotetramers . on the basis of the macrocycles described 
 above , the cyclic dimer , cyclic trimer , and cyclotetramer of the 1,2-phenylene , 
 1,4-biphenylene , and 1,4-terphenylene ethynylene macrocycles 
 were computationally modeled . geometry optimization and single - point 
 energies were calculated at various levels of theory using gaussian 
 03 , and the alkyl chains were omitted 
 for computational ease . the structures shown are from the b3lyp/6 - 31g(d ) 
 geometry optimization , but the structures for the geometries optimized 
 with every method do not differ appreciably . the energies tabulated 
 in table 3 are per repeat unit and normalized 
 to the cyclotrimer for each analogous series . for the o - arylene ethynylene cyclooligomers , it 
 is no surprise that the d2h cyclodimer 24c is much higher in energy than 
 either the d3h cyclotrimer 24a or d2d tetramer 24b . the incomplete treatment of the closed -system 
 in the molecular mechanics force field is most likely the source of 
 the difference in repeat unit strain calculated for the cyclotetramer 24b ; the puckered ring of 24b is predicted to 
 be as nearly strainless as cyclotrimer 24a by semiempirical , 
 ab initio , and density functional methods but not by molecular mechanics . the c14h8 repeat units in cyclodimer c2h1d are 10 
 kcal / mol higher in energy than those in c31a , and the two para - substituted rings 
 are predicted to be coplanar with one another , which gives c21d the appearance of an extended 
 cyclophane . the aryl aryl dihedral 
 angle ( 57 ) as well as a similar alkyne bond angle to that of 
 the cyclic trimer . these structural similarities , despite the pucker 
 in the cyclotetramer ring , contribute its lack of strain ; the cyclotrimer 
 and cyclotetramer are nearly isoenergetic on the basis of each repeat 
 unit . the constrained cyclic array of the terphenyl dimer c2 symmetric 2d forces the 
 two para - substituted rings to be nearly coplanar , 
 while being orthogonal to the ortho - substituted ring . the c20h12 repeat units are calculated to be 
 8 kcal / mol more strained in 2d than in 2a , a smaller difference than that calculated in the biphenyl 
 macrocycles . the optimized geometry of the cyclotrimer 2a is c3 symmetric and features a nearly 
 all - planar system in which only the central p - phenylene 
 of the terphenyl unit is twisted out of the plane . as a result , there 
 are three planar diphenylacetylene moieties within 2a , a structural feature that is shared by the optimized geometry of c2 symmetric 2e . the lack of angle 
 strain in the alkykyl moieties in both 2a and 2e is a contributing factor making them nearly isoenergetic . in all cases , the cyclodimers have the highest energy per monomer 
 unit compared to the respective cyclotrimers or cyclotetramers , which 
 in each case are nearly isoenergetic . there is a relationship between 
 the number of p - phenylene units in the macrocycle 
 and the relative strain of the cyclodimer ; presumably , the angle strain 
 of the alkynyl moieties is shared among additional phenylene units 
 and the overall strain of the repeat unit is reduced . the average 
 sp carbon bond angle is 155.4 in 24c , 166.5 
 in 1d , and 170.0 in 2d , and it is 
 evident that smaller deviations from the ideal bond angle in the alkynyl 
 carbons is accompanied by a reduction in the strain energy . the structural 
 similarities shared between 1a and 1e as 
 well as 2a and 2e shown in table 1 reflect their isoenergetic relationships . h interaction present in the biphenyl 
 and terphenyl macrocycles that is as significant in setting the aryl aryl 
 dihedral as the distance between the 2- and 2-hydrogens ; these 
 distances are only significant in the cyclic trimers and tetramers 
 since the cyclic dimer has a near orthogonal biphenyl dihedral angle 
 ( table 2 ) . the observation of 
 cyclic dimer 2c in the macrocyclization 
 of 3b suggests that the strain calculated per repeat 
 unit is not great enough to prevent the irreversible , kinetic formation 
 of 2c . the larger strain calculated for the biphenyl 
 dimer 1d suggests that strain may be playing a role in 
 favoring the formation of cyclotrimer 1b and cyclotetramer 1c in the macrocyclization of 3a . energies are in kcal mol per repeat 
 unit of cyclooligomer and are referenced to the cyclic 
 trimer repeat unit energy for each set of cyclooligomers . the absorption and emission spectra 
 of the novel macrocycles described above were recorded in a variety 
 of solvents , since solvent polarity has been shown to affect the absorption 
 and emission wavelength as well as the quantum yields (  ) of 
 organic molecules . their poor solubility 
 in some solvents such as pentane limited full comparisons of all of 
 the macrocycles , but in benzene , thf and chcl3 , their max and max were determined . compound 1b exhibited an absorption 
 maximum at 296 nm , with shoulders near 264 and 330 nm . cyclotetramer 2b exhibited two nearly equally intense absorptions at 282 
 and 301 nm , and these two maxima were observed in other solvents as 
 well . cyclotrimer and cyclodimer 2b and 2c exhibited more similar spectra in pentane , with single dominant 
 absorption maxima at 312 and 306 nm , respectively . it should be noted 
 that accurate molar absorptivities were not obtained for 2b and 2c because of the formation of insoluble precipitate 
 during the measurement of the spectra in pentane . all of the 
 macrocycles were more soluble in benzene , and their 
 absorption spectra are shown in figure 4 . the 
 spectra of linear trimers 23a and 23b were 
 also obtained in benzene . the max of biphenylene 
 linear trimer 23a , 299 nm , does not change appreciably 
 upon cyclization to 1a , which has a max of 298 nm . alternatively , the max of terphenylene 
 linear trimer 23b , 295 nm , is shifted bathochromatically 
 by 8 nm upon cyclization to cyclic trimer 2a ( max = 303 nm ) . this could arise from an increase in conjugation 
 upon moving from the linear to the cyclic system . both 1b and 2b are red - shifted 
 by 56 nm compared to their unsubstituted analogs , 1a and 2a . cyclic tetramer 1c is also red - shifted 
 6 nm compared to cyclic trimer 1b and has a much broader 
 and less intense uv absorption band . all of the terphenylene macrocycles 
 also showed broad absorptions , but cyclic dimer 2c and 
 cyclic trimer 2b had very similar spectra . the absorption 
 spectra of the macrocycles in thf show similar trends to those seen 
 in the less polar benzene and pentane . all of the terphenylene macrocycles 2a  c exhibit a bathochromatic shift in their absorption maxima 
 in chcl3 compared to thf , while no such shift is observed 
 for the biphenylene macrocycles 1a  c . just as was observed in benzene , the max of linear 
 trimer 23a , 298 nm , is very similar to that of cyclic 
 trimer 1a , 297 nm , while terphenylene linear trimer 23b has a max of 293 , 10 nm blueshifted 
 compared to the cyclic trimer 2a which has a max of 303 nm . alkyl substitution again redshifts the max of cyclic trimers , from 297 nm for 1a to 302 
 nm for 1b and from 303 for 2a to 315 nm 
 for 2b , which was the largest max observed 
 in the solvents examined . as observed in previous solvents , biphenyl 
 cyclotetramer 1c exhibits two max at 
 286 and 308 nm , and cyclic dimer 2c exhibits a broad 
 maximum with a relatively small molar absorptivity ( figure 5 ) . there is little to no solvent 
 dependence on absorption for macrocycles 1a  c and 2a  c . cyclotrimers 1a , 1b and 2a or for cyclotetramer 1c or cyclodimer 2c . only substituted biphenylene 
 cyclotrimer 1b and terphenylene cyclotrimer 2b exhibited a significant 
 solvatochromic shifts , and while cyclotetramer 1c exhibits 
 two nearly identical max in pentane , thf and chloroform , 
 it has only a single broad max in benzene . the relationship between the structure of the macrocycle and its 
 absorption spectrum should depend on the extent of conjugation around 
 the macrocyclic ring . the three central p - phenylene 
 aromatic rings of the terphenylene moiety in 2b are 47 
 out of the macrocyclic plane , as are the three p - phenylenes 
 in 1b . it is possible that the conjugation around the 
 macrocyclic ring is not interrupted to a significant extent , thus 
 causing 2b to exhibit a more red - shifted max compared to 1b which has a smaller  
 system . this trend exists in all solvents tested , although the extent 
 of the shift increases as solvent polarity decreased . chcl3 and thf show a shift of 12 nm each , while nonpolar solvents 
 benzene and pentane cause a larger red shift of 9 and 18 nm , respectively . several groups have examined the varying effects of ring strain 
 on absorption properties of conjugated ethynylic systems . in the case of the biphenylene and terphenylene 
 systems , 1e suggest that all biphenylene macrocycles synthesized , 1a , 1b , and 1c , are all essentially 
 strain - free . aryl dihedral angle is also nearly identical 
 in 1a and 1e , and both the planar cyclic 
 trimer and puckered cyclic tetramer differ only in the disposition 
 of the identical biphenylene ethynylene units ; these units 
 are coplanar in the cyclic trimer and are not in the cyclic tetramer . 
 in all solvents examined excepting benzene where the solvent may have 
 partially obscured the spectrum , trimer 1b showed a single , 
 broad max at around 300 nm , and tetramer 1c showed two max , one 15 nm shorter and 
 another 5 nm longer wavelength ( table 3 ) . it should be noted 
 that the two - dimensional -network is disrupted in the cyclotetramer 
 by the ring pucker , which may explain the lower molar absorptivities 
 of the cyclic tetramer in each solvent examined . cyclic dimer 2c and cyclic trimer 2b exhibit very similar 
 spectra in benzene and thf , and slightly shifted spectra in pentane 
 and chloroform . deformation from planarity by the ethynyl - substituted p - phenylene ring in the terphenyl cyclotrimer , 2b is amplified from 6 to near orthongonality , 87 , by removing 
 a single repeat unit to form the terphenyl cyclodimer 2c . despite this interruption in the cyclic -nework , the uv this suggests that either -conjugation 
 is not occurring in both systems and absorptions are a result of individual 
 subunits or that delocalization about the macrocycles is not disrupted . 
 in all cases , 2b exhibits greater molar absorptivity 
 which could be the result of a larger number of absorbing moieties 
 in the cyclic trimer versus the cyclic dimer . solutions of all of the macrocycles 1 and 2 as well as the linear trimers 23a and 23b are highly fluorescent ( figure 6 ) . the emission 
 properties of these compounds were analyzed in benzene and their fluorescence 
 quantum yields were determined using pyrene as a standard . all macrocycles 
 displayed large stokes shifts which are indicative of large conjugated 
 arylene ethynylene macrocycles ( see table 4 ) . the absorbance spectrum 
 of biphenylene linear trimer 23a and biphenylene cyclic 
 trimer 1a are very similar , 
 but the single emission maximum exhibited by linear trimer 23a at 381 nm shifts to 418 nm upon ring closure to form 1a . no such large shift is observed upon ring closure of terphenylene 
 linear trimer 23b with an emission maxima of 381 and 
 399 nm to terphenylene cyclic trimer 2a with emission 
 maxima of 390 and 406 nm . comparison of the fluorescence spectra of 1a to 1b and 2a to 2b indicates that n - octyl substitution causes only 
 small shifts in the emission maxima . cyclic tetramer 1c displays two em at 382 and 401 nm , at much shorter 
 wavelengths than 1a and 1b ; the puckering 
 of the macrocyclic ring not only affects the absorbance spectrum of 
 1c , but its emission spectrum . all terphenylene macrocycles emit two 
 em at similar wavelengths to 1c , at 390 
 and 405 nm . cyclic dimer 2c shows similar emission 
 properties to that of the cyclic trimer even though the p - phenylenes are orthogonal to the o - phenylene . the 
 dihedral angles of the terphenyl moiety do not appear to perturb the 
 optical properties of these systems . while 1a and 1b exhibit stokes shifts 
 of 120 nm , all of the other macrocycles exhibit stokes shifts of 80 
 and 100 nm . the larger stokes shifts for the biphenylene cyclic trimers 
 could indicate a more complete planarization of the macrocycle in 1a and 1b than the other macrocycles ; extending 
 the conjugation throughout the biphenylene cyclotrimers requires only 
 a single close h  h and a single close c  h contact , while 
 the biphenylene cyclotetramer can not achieve planarity and greater 
 conjugation without involving a significant amount of angle strain 
 and the terphenylenes would require four close h one possible cause 
 for the stokes shifts observed could be aggregation 
 of the macrocycles in solution , which has been observed for similar 
 structures . to test this hypothesis , we obtained the nmr spectra of 
 solutions of 1b in benzene at concentrations higher than 
 those used to obtain the fluorescence spectrum of 1b ( figure 7 ) . if 1b had been aggregating in the 
 0.066 mm solution used in the fluorescence experiment , it should be 
 doing so at higher concentrations as well . since the nmr chemical 
 shifts of all of the aromatic protons in 1b show no concentration 
 dependence above that concentration , it seems likely that no aggregation 
 would have taken place at the lower concentration . concentration - dependent 
 nmr chemical shifts of 1b in 
 c6d6 ; fluorescence spectra were observed at 
 0.066 mm . all macrocycles exhibit fairly 
 low quantum yields (  ) in 
 benzene compared to larger arylene ethynylene macrocycles ( table 4 ) . however , these systems do not contain long linear conjugated 
 pathways which has been correlated to high quantum yields . quantum yields for the biphenyl macrocycles 
 range from 0.02 for 1b to 0.04 for 1c while 
 the quantum yields for terphenyl macrocycles are slightly more efficient 
 ranging 0.04 for both 2a and 23b to 0.06 
 for 2b . in an effort to synthesize 
 precursors of short carbon single - walled 
 nanotubes , cyclic trimers containing biphenylene and p - terphenylene ethynylene units were constructed via linear , split - pool 
 approaches to give unsubstituted macrocycles 1a and 2a . more soluble alkyl - substituted analogues 1b and 2b were also synthesized , utilizing statistical 
 macrocyclizations of monomers made possible by the increased solubility . these statistical macrocyclizations also yielded a cyclotetramer 1c in the biphenylene system and a cyclodimer 2c in the p - terphenylene system ; these alternative 
 cyclooligomers were separable from the cyclotrimers by exhaustive 
 column chromatography . computational geometry optimizations suggest 
 that the cyclic dimer is not energetically accessible in the statistical 
 macrocyclization of 16b , while a lesser degree of angle 
 strain in the terphenylene monomer 17b allows formation 
 of cyclodimer 2c . all of the macrocycles obtained absorb 
 around 300 nm , but the cyclotrimers 1a and 1b exhibit larger stokes shifts in their fluorescence emission spectra 
 than the other macrocycles observed . further studies are currently 
 being conducted to determine if multiple cycloadditions can be carried 
 out on the alkynes present in these macrocycles to convert them into 
 arylene cyclooligomers that can be oxidized to make carbon nanobelts . 4-iodoaniline 
 ( 10.004 g , 45.67 mmol , 
 1.00 equiv ) was dissolved in 380 ml of acetonitrile , 160 ml of water , 
 and 16.0 ml of concentrated hydrochloric acid and cooled to 0 c . 
 a solution of 1.1 equiv of nano2 ( 3.321 g , 48.14 mmol , 
 1.05 equiv ) in 20 ml water was added slowly via syringe and the mixture 
 stirred 45 min at 0 c . the mixture was transferred to a flask 
 containing k2co3 ( 21.001 g , 151.9 mmol , 3.32 
 equiv ) and diethylamine ( 9.5 ml , 91.81 mmol , 2.00 equiv ) in 250 ml 
 of h2o at 0 c . the reaction was allowed to slowly 
 warm to room temperature and stirred for 2 h before being extracted 
 with diethyl ether . the combined organic layers washed with brine , 
 dried over magnesium sulfate , filtered , and concentrated in vacuo . the crude product was then purified by flash chromatography using 
 5% diethyl ether in hexanes to afford 13.43 g of the desired product 
 as an orange oil ( 97% yield ) : h nmr ( 500 mhz , cdcl3 )  7.61 ( d , j = 8.8 hz , 2h ) , 7.16 
 ( d , j = 8.8 hz , 2h ) , 3.74 ( q , j = 7.3 , 4h ) , 1.25 ( br t , 6h ) ; c nmr ( 125 mhz , cdcl3 )  150.9 , 137.6 , 122.4 , 88.9 ; ir ( cm ) 2974 , 2933 , 2871 , 1475 , 1420 , 1391 , 1341 , 1238 , 1198 , 1108 , 1093 , 
 1001 , 828 ; ms ( ci - isobutane ) [ mh ] 304.6 m / z . a 25 ml round - bottomed 
 flask 
 was charged with 1-bromo-2-iodobenzene ( 2.697 g , 9.53 mmol , 1.00 equiv ) , 
 cl2pd(pph3)2 ( 0.198 g , 0.282 mmol , 
 0.03 equiv ) , cui ( 0.051 g , 0.267 mmol , 0.03 equiv ) , triisopropylsilylethynylene 
 ( 2.3 ml , 10.25 mmol , 1.07 equiv ) , and 20 ml of 1:1 thf / et3n . the solution was stirred at room temperature for 24 h before being 
 concentrated in vacuo . the crude residue was dissolved in diethyl 
 ether and washed with saturated nh4cl ( aq ) . the organic 
 layers were dried over mgso4 , filtered , and concentrated 
 in vacuo . purification of the crude material by flash column chromatography 
 yielded 3.18 g of the product as a yellow oil ( 99% yield ) : h nmr ( 500 mhz , cdcl3 )  7.56 ( d , j = 8.2 hz , 1h ) , 7.50 ( d j = 7.74 hz , 1h ) , 7.22 ( t , j = 7.74 hz , 1h ) , 7.13 ( t , j = 7.95 hz , 
 1h ) , 1.13 ( br s , 21h ) ; c nmr ( 125 mhz , cdcl3 )  134.1 , 132.6 , 129.6 , 127.0 , 126.0 , 125.9 , 105.0 , 96.4 , 
 18.9 , 11.6 ; ir ( cm ) 2943 , 2865 , 2161 , 1464 , 1220 , 
 1047 , 908 , 883 , 834 , 753 , 678 ; ms ( ci - isobutane ) [ mh ] 
 295.5 , 296.4 m / z method a : 1,1-diethyl-3-(4-iodophenyl)triazene 
 ( 1.931 g , 6.370 mmol , 1.00 equiv ) was combined with bis(pinacolato)diboron 
 ( 1.947 g , 7.667 mmol , 1.20 equiv ) , cl2pd(dppf ) ( 0.143 g , 
 0.195 mmol , 0.03 equiv ) , and koac that had been dried under vacuum 
 ( 1.875 g , 19.11 mmol , 3.00 ) . deoxygenated dmso ( 52 ml ) was added , 
 and the reaction was heated to 80 c and monitored by tlc ( 5% 
 diethyl ether in hexanes ) . upon consumption of triazene starting material , the 
 organic layers were combined , washed with satd nh4cl ( aq ) , 
 dried over mgso4 , and concentrated in vacuo . crude material 
 was purified by flash chromatography using 5% diethyl ether in hexanes 
 as the eluent to afford 1.931 g ( 74% yield ) of the desired product 
 as a white solid , mp 119120 c . the product can also 
 be purified by filtration through a silica plug ( 10% ethyl acetate 
 in hexanes ) followed by recrystallization from 2-propanol : h nmr ( 500 mhz , cdcl3 )  7.77 ( d , j = 8.3 hz , 2h ) , 7.40 ( d , j = 8.3 hz , 2h ) , 3.77 ( q , j = 7.3 , 4h ) , 1.35 ( s , 12h ) , 1.27 ( br t , j = 6.8 hz , 6h ) ; c nmr ( 125 mhz , cdcl3 )  
 153.6 , 135.5 , 119.7 , 83.5 , 24.8 ; ir ( cm ) 2979 , 
 1602 , 1391 , 1351 , 1320 , 1139 , 1087 , 857 , 655 ; hrms ( esi ) m / z calcd for c16h26bn3o2h ( [ m + h ] ) 304.2196 , found 
 304.2194 . method b : 6 n hcl ( 27.10 ml , 162.51 mmol , 
 8.9 equiv ) was added dropwise to a solution of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)aniline 
 ( 4.035 g , 18.42 mmol , 1 equiv ) in 62.40 ml of diethyl ether , 48.00 
 ml of tetrahydrofuran , and 9.60 ml of acetonitrile chilled to 5 
 c in an ice  salt bath . a solution of nano2 ( 4.3255 g , 62.69 mmol , 3.5 equiv ) in 21.60 ml of water and 9.69 
 ml of acetonitrile was added dropwise , and the reaction was stirred 
 at 5 c for 30 min before being slowly transferred via 
 cannula to a flask containing diethylamine ( 43.45 ml , 419.98 mmol , 
 23 equiv ) and k2co3 ( 12.640 g , 91.46 mmol , 5 
 equiv ) in 79.20 ml of water and 174.00 ml of acetonitrile at 0 c . the reaction was stirred for 45 min while being warmed to room temperature 
 before being diluted with satd nacl and extracted with et2o . the organics were washed with h2o , dried over mgso4 , filtered , and concentrated in vacuo to give a brown crystal . crude material was purified by extraction with hexanes and concentration 
 in vacuo to afford 4.7567 g ( 85% yield ) of orange crystals : h nmr ( 500 mhz , cdcl3 )  7.77 ( d , j = 8.3 hz , 2h ) , 7.40 ( d , j = 8.3 hz , 2h ) , 3.77 ( q , j = 7.3 , 4h ) , 1.35 ( s , 12h ) , 1.27 ( br t , j = 6.8 hz , 6h ) ; c nmr ( 125 mhz , cdcl3 )  
 153.6 , 135.5 , 119.7 , 83.5 , 24.8 ; ir ( cm ) 2979 , 
 1602 , 1391 , 1351 , 1320 , 1139 , 1087 , 857 , 655 ; hrms ( esi ) m / z calcd for c16h26bn3o2h ( [ m + h ] ) 304.2196 , found 304.2194 . ( 2-bromophenylethynyl)triisopropylsilane 
 ( 2.067 g , 6.13 mmol , 1.00 equiv ) was added to a flask fitted with 
 a sealed reflux condenser and charged with 3,3-diethyl-1-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl)triaz-1-ene 
 ( 2.787 g , 9.19 mmol , 1.5 equiv ) , powdered potassium phosphate ( tribasic ) 
 ( 6.51 g , 30.65 mmol , 5 equiv ) , and pdcl2(dppf ) ( 0.150 g , 
 0.184 mmol , 0.03 equiv ) . the flask was purged with nitrogen , and 50 
 ml of dexoygenated 1,2-dimethoxyethane was added via syringe . the 
 reaction was stirred at reflux for 624 h , until tlc indicated 
 completion ( some side products run at the same rf as the bromide , making exact assignment 
 of completion difficult ) . the reaction mixture was then cooled , and 
 the dme was removed in vacuo . the combined organic layers were washed 
 with brine , dried over magnesium sulfate , filtered , and concentrated 
 in vacuo . purification was effected by flash column chromatography 
 over neutral alumina with a mobile phase of 5% diethyl ether in hexanes 
 to obtain 2.66 g of the biphenyl product as an orange oil ( 95% yield ) : h nmr ( 500 mhz , cdcl3 )  7.59 ( d , j = 8.3 hz , 3h ) , 7.43 ( d , j = 8.3 hz , 2h ) , 
 7.38 ( d , j = 7.8 hz , 1h ) , 7.33 ( t , j = 7.3 hz , 1h ) , 7.23 ( t , j = 7.8 hz , 1h ) , 3.76 ( q , j = 7.3 hz , 4h ) , 1.27 ( t , j = 7.3 hz , 6h ) , 
 1.03 ( s , 21h ) ; c nmr ( 125 mhz , cdcl3 )  
 150.48 , 144.0 , 137.1 , 133.9 , 129.7 , 129.3 , 128.4 , 126.5 , 121.7 , 119.9 , 
 106.6 , 93.9 , 18.6 , 11.3 ; ir ( cm ) 2940 , 2864 , 2151 , 
 1464 , 1397 , 1330 , 1235 , 1096 , 883 , 835 , 761 , 677 ; hrms ( esi ) m / z calcd for c27h39n3sih ( [ m + h ] ) 434.2992 , found 434.2991 . compound 3a ( 1.855 g , 4.277 mmol , 
 1.00 equiv ) was dissolved in 10 ml of methyl iodide in a sealable 
 reaction flask , degassed , backfilled with nitrogen , sealed , and heated 
 to 125 c for 44 h. after cooling , the methyl iodide was removed 
 by evaporation and the product purified by flash chromatography over 
 silica with 5% diethyl ether in hexanes to isolate 1.950 g of a yellow 
 oil ( 99% yield ) : h nmr ( 500 mhz , cdcl3 )  
 7.70 ( d , j = 8.3 hz , 2h ) , 7.59 ( d , j = 7.8 hz , 1h ) , 7.277.37 ( m , 5h ) , 1.01 ( s , 21h ) ; c nmr ( 125 mhz , cdcl3 )  143.1 , 140.1 , 137.0 , 133.7 , 
 131.2 , 129.0 , 128.5 , 127.2 , 121.9 , 105.9 , 94.6 , 93.1 , 18.5 , 11.3 ; 
 ir ( cm ) 2940 , 2863 , 2152 , 1469 , 1386 , 1000 , 883 , 
 820 , 758 , 677 ; hrms ( ei ) m / z calcd 
 for c23h29isi ( [ m ] ) 460.1083 , found 
 460.1091 . tbaf ( 1 m ) in thf ( 2.0 ml , 2.00 mmol , 4.35 equiv ) was added to a 
 solution of 9 ( 0.212 g , 0.460 mmol , 1.00 equiv ) in 3 
 ml of thf . the reaction was stirred at room temperature and monitored 
 by tlc . upon disappearance of starting material , the reaction was 
 concentrated to one - third of its original volume , diluted with 25 
 ml of h2o , and extracted with diethyl ether ( 3  50 
 ml ) . the crude material was purified via 
 flash chromatography using 5% diethyl ether in hexane to afford 0.134 
 g ( 96% yield ) of a reddish oil : h nmr ( 500 mhz , cdcl3 )  7.78 ( d , j = 7.0 hz , 2h ) , 7.64 
 ( d , j = 7.5 hz , 1h ) , 7.42 ( t , j = 
 6.5 hz , 1h ) , 7.377.34 ( m , 4h ) , 3.08 ( s , 1h ) ; c nmr ( 125 mhz , cdcl3 )  143.1 , 139.7 , 137.1 , 133.9 , 
 131.1 , 129.2 , 129.0 , 127.3 , 120.3 , 93.6 , 80.6 ; ir ( neat , cm ) 3274 , 3061 , 1583,1472 ; hrms ( esi ) m / z calcd for c14h10i ( [ m + h ] ) 16a ( 0.060 g , 0.197 mmol , 
 1.00 equiv ) , cl2pd(pph3)2 ( 0.007 
 g , 0.010 mmol , 0.05 equiv ) , 
 and cui ( 0.004 g , 0.020 mmol , 0.11 equiv ) were combined and dissolved 
 in 10.6 ml of thf and 0.2 ml of et3n . the reaction was 
 stirred for 10 days at room temperature before being diluted with 
 h2o and extracted with et2o ( 3  20 ml ) . the organics were washed over brine , dried over mgso4 , 
 filtered , and concentrated in vacuo . the crude material was run through 
 a flash column to afford a white solid mixture of cyclic and linear 
 oligomers that resisted further purification . compound 3a ( 0.655 g , 1.510 
 mmol , 
 1 equiv ) was dissolved in 5 ml of methanol . a solution of 1 m tbaf 
 in thf ( 7.6 ml , 7.50 mmol , 4.97 equiv ) was added ; the reaction was 
 then stirred at room temperature and monitored by tlc . upon disappearance 
 of starting material , the reaction was concentrated to one - third its 
 original volume , diluted with 50 ml of h2o , and extracted 
 with diethyl ether ( 3  50 ml ) . the organic layers were combined , 
 dried over mgso4 , and concentrated in vacuo . the crude 
 material was purified via flash chromatography using 5% diethyl ether 
 in hexane to afford 0.376 g ( 90% yield ) of a yellow oil : h nmr ( 500 mhz , cdcl3 )  7.62 ( d , j = 8.0 hz , 1h ) , 7.59 ( d , j = 8.2 hz , 2h ) , 7.50 ( d , j = 8.2 hz , 2h ) , 7.417.40 hz ( m , 2h ) , 7.307.27 
 ( m , 1h ) , 3.80 ( q , j = 7.0 hz , 4h ) , 3.06 ( s , 1h ) , 
 1.30 ( t , j = 7.0 hz , 6h ) ; c nmr ( 125 
 mhz , cdcl3 )  150.6 , 144.4 , 136.9 , 133.8 , 129.7 , 
 129.5 , 128.9 , 126.6 , 120.3 , 119.9 , 83.3 , 80.0 . ir ( cm ) 3284 , 1330 , 1229 , 837 ; hrms ( photospray ionization ) m / z calcd for c18h20n3 ( [ m + h ] ) 278.1657 , found 278.1664 . a 50 ml round - bottomed flask was charged 
 with 9 ( 0.223 g , 0.484 mmol , 1.00 equiv ) , 19a ( 0.180 g , 0.649 mmol , 1.34 equiv ) , and cl2pd(pph3)2 ( 0.020 g , 0.0285 mmol , 0.06 equiv ) and flushed 
 with n2 . to this 20 ml of deoxygenated thf / et3n ( 1:1 v / v ) was added , and the reaction flask was sparged with n2 for 5 min . cui was added and the reaction stirred at 40 c 
 for 18 h. upon completion , the reaction was diluted with 25 ml of 
 h2o and extracted with diethyl ether ( 3  25 ml ) . the organics were combined , washed with satd nh4cl , dried 
 over mgso4 , and concentrated in vacuo . the crude material 
 was purified via flash chromatography using 5% diethyl ether in hexanes 
 to give 0.226 g ( 77% ) of the desired product as a yellow oil : h nmr ( 500 mhz , cdcl3 )  7.72 ( d , j = 8.5 hz , 2h ) , 7.70 ( d , j = 7.9 hz , 1h ) , 
 7.62 ( d , j = 7.8 hz , 1h ) , 7.577.54 ( m , 4h ) , 
 7.48 ( d , j = 8.0 hz , 1h ) , 7.43 ( d , j = 7.9 hz , 2h ) , 7.40 ( d , j = 8.3 hz , 1h ) , 7.387.27 
 ( m , 4h ) , 3.82 ( q , 7.2 hz , 4h ) , 1.31 ( t , j = 7.1 hz , 
 6h ) , 1.05 ( s , 21h ) ; c nmr ( 125 mhz , cdcl3 ) 
  150.6 , 143.7 , 143.5 , 140.2 , 137.2 , 133.8 , 133.0 130.9 , 129.8 , 
 129.5 , 129.2 , 129.1 , 128.5 , 127.1 , 126.7 , 122.5 , 121.8 , 121.4 , 119.9 , 
 106.0 , 94.4 , 92.3 , 89.8 , 18.55 , 11.3 ; ir ( cm ) 
 2942 , 2860 , 2356 , 1460 , 1334 , 1229 , 830 ; hrms ( maldi ) m / z calcd for c41h48n3si ( [ m + h ] ) 610.3618 , found 610.3616 . compound 20a ( 0.206 g , 0.338 
 mmol , 1.00 equiv ) and 4 ml of mei were placed in a sealed tube flask 
 under an atmosphere of n2 . the reaction was heated to 125 
 c for 18 h before being allowed to cool to room temperature . the residue was dissolved in 
 10 ml of ch2cl2 , washed with h2o , 
 dried over mgso4 , and concentrated in vacuo . the crude 
 product was purified via flash chromatography using 5% etoac in hexanes 
 as the eluent and afforded 0.202 g ( 94% yield ) of the desired product 
 as a yellow oil : h nmr ( 500 mhz , cdcl3 )  
 7.81 ( d , j = 8.5 hz , 2h ) , 7.69 ( d , j = 7.7 hz , 1h ) , 7.62 ( d , j = 7.5 hz , 1h ) , 7.59 ( d , j = 8.0 hz , 2h ) , 7.46 ( d , j = 8.0 hz , 2h ) , 
 7.417.38 ( m , 2h ) , 7.377.35 ( m , 5h ) , 7.327.29 
 ( m , 1h ) 1.05 ( s , 21h ) ; c nmr ( 125 mhz , cdcl3 )  143.3 , 142.5 , 140.5 , 140.0 , 137.0 , 133.8 , 133.0 , 131.3 , 
 130.9 , 129.3 , 129.2 , 128.6 , 128.5 , 127.4 , 127.2 , 122.1 , 121.8 , 121.5 , 
 106.0 , 94.5 , 93.4 , 92.8 , 89.1 , 18.6 , 11.3 ; ir ( cm ) 2940 , 2865 , 2148 , 1467 , 1000 , 756 ; hrms ( esi ) m / z calcd for c37h38isi ( [ m 
 + h ] ) 637.1787 , found 637.1777 . compound 21a ( 0.091 g , 0.142 mmol , 1.00 equiv ) , 3,3-diethyl-1-(2-ethynylbiphenyl-4-yl)triaz-1-ene 
 ( 0.035 g , 0.153 mmol , 1.08 equiv ) , cl2pd(pph3)2 ( 0.005 g , 0.007 mmol , 0.05 equiv ) , and cui ( 0.002 g , 
 0.010 mmol , 0.07 equiv ) were dissolved in 5 ml of deoxygenated thf 
 and 5 ml of deoxygenated triethylamine . the solution was heated to 
 40 c overnight before being diluted with satd nh4cl and extracted with etoac . the organics were washed with satd nh4cl , dried over mgso4 , filtered , and concentrated 
 in vacuo . the crude material was purified by flash chromatography 
 using 10% etoac in hexanes to afford 0.075 g of the desired product 
 as an off - white waxy solid ( 67% yield ) : h nmr ( 500 mhz , 
 cdcl3 )  7.727.66 ( m , 5h ) , 7.62 ( d , j = 7.5 hz , 1h ) , 7.587.52 ( m , 6h ) , 7.507.28 
 ( m , 8h ) , 3.77 ( q , j = 7.2 hz , 4h ) , 1.28 ( t , j = 7.2 hz ) , 1.02 ( s , 21h ) ; c nmr ( 125 mhz , 
 cdcl3 )  143.7 , 143.3 , 143.1 , 140.4 , 140.2 , 137.2 , 
 133.8 , 133.0 , 132.9 , 131.0 , 130.9 , 129.85 , 129.4 , 129.3 , 129.27 , 128.18 , 
 128.5 , 127.2 , 127.0 , 126.6 , 122.7 , 122.2 , 121.8 , 121.5 , 121.4 , 119.0 , 
 106.0 , 94.4 , 92.6 , 92.2 , 90.2 , 89.3 , 18.5 , 11.2 ; ir ( neat , cm ) : 2932 , 2860 , 2154 , 1473 , 1096 , 836 , 744 ; hrms ( esi ) m / z calcd for c55h56n3si ( [ m + h ] ) 786.4244 , found 786.4257 . compound 22a ( 0.039 g , 0.0478 
 mmol , 1.0 equiv ) was sealed in a flask with 1 ml of mei and heated 
 to 120 c for 48 h. excess mei was allowed to evaporate after 
 the reaction mixture cooled . the crude residue was purified by flash 
 chromatography using 10% etoac in hexanes as eluent to afford 0.039 
 g of the desired product as a light yellow waxy solid ( 98% yield ) : h nmr ( 500 mhz , cdcl3 )  7.81 ( d , j = 8.0 hz , 2h ) , 7.70 7.67 ( m , 4h ) , 7.61 ( d , j = 8.0 hz , 1h ) , 7.57 ( d , j = 8.5 hz , 2h ) , 
 7.477.35 ( m , 14h ) , 7.327.27 ( m , 1h ) 1.05 ( s , 21h ) ; c nmr ( 125 mhz , cdcl3 )  143.3 , 142.9 , 140.6 , 
 140.5 , 140.0 , 137.0 , 133.8 , 133.1 , 133.0 , 131.2 , 130.9 , 129.4 , 129.4 , 
 129.3 , 129.2 , 128.7 , 128.5 , 128.5 , 127.4 , 127.3 , 127.1 , 122.3 , 122.2 , 
 121.9 , 121.6 , 121.4 , 106.04 , 94.4 , 93.4 , 92.7 , 92.6 , 89.5 , 89.3 , 18.5 , 
 11.2 ; ir ( neat , cm ) 2802 , 2847 , 2356 , 1726 , 1457 , 
 1273 , 761 ; hrms ( esi ) m / z calcd 
 for c51h46isi ( [ m + h ] ) 813.2413 , 
 found 813.2406 . compound 23a ( 0.039 g , 0.0463 mmol , 1.00 equiv ) was dissolved in 0.25 ml of thf 
 before 0.100 ml of 1 m tbaf in thf ( 0.100 ml , 0.100 mmol , 2.16 equiv ) 
 was added . after 5 min , the reaction showed no signs of starting material 
 by tlc and was diluted with et2o . the organics were washed 
 with satd nh4cl ( aq ) , dried over mgso4 , filtered , 
 and rotovapped . the crude material was purified by flash chromatography 
 using 5% etoac in hexanes to afford the desired compound which was 
 used in the following reaction without further characterization . compound 24a ( assuming 100% 
 conversion in previous reaction : 0.032 g , 0.0463 mmol , 1.00 equiv ) 
 was dissolved in 1 ml of et3n and charged in a gastight 
 syringe in a syringe pump . pd(dba)2 ( 0.039 g 0.068 mmol , 
 1.42 equiv ) , cui ( 0.015 g , 0.079 mmol , 1.71 equiv ) , and pph3 ( 0.076 g , 0.290 mmol , 6.26 equiv ) were dissolved in 11.6 ml of et3n . the iodoalkyne trimer was added at a rate of 0.1 ml per 
 hour , and the reaction was allowed to stir for an additional 12 h 
 after the addition was complete . the reaction was diluted with sat 
 nh4cl ( aq ) and extracted with etoac . the organic phases 
 were dried over mgso4 , filtered , and concentrated in vacuo . the crude material was purified using 15% ch2cl2 in hexanes to afford 11 mg ( 45% yield ) of the desired macrocycle 
 as a white solid : mp 282291 c ; h nmr ( 500 
 mhz , cdcl3 )  7.75 ( d , j = 8.4 hz , 
 6h ) , 7.67 ( d , j = 7.4 hz , 3h ) , 7.507.48 ( m , 9h ) , 7.45 ( t , j = 7.8 hz , 3h ) , 7.36 ( t , j = 7.4 hz , 3h ) ; c nmr ( 125 mhz , cdcl3 )  
 143.7 , 140.9 , 133.4 , 131.5 , 130.0 , 129.9 , 129.5 , 128.1 , 123.1 , 122.2 , 
 93.4 , 90.3 ; hrms ( maldi ) m / z calcd 
 for c42h24 ( [ m ] ) 528.1872 , found 
 528.1864 . compound 9 ( 1.923 g , 4.18 
 mmol , 1.00 equiv ) was added to a flask with 6 ( 1.90 g , 
 6.27 mmol , 1.5 equiv ) , boronate , k3po4 ( 4.52 
 g , 21.3 mmol , 5.1 equiv ) , and pdcl2(dppf ) ( 0.10 g , 0.125 
 mmol , 0.03 equiv ) . the reaction was refluxed for 20 h and cooled 
 to room temperature , the solvent was removed in vacuo , and the organic 
 products were extracted from water with diethyl ether . the combined 
 organic layers were washed with brine , dried over magnesium sulfate , 
 filtered , and concentrated in vacuo . purification over neutral alumina 
 with 25% methylene chloride in hexanes afforded 1.38 g of the product 
 as a pale yellow solid : mp 110111 c ( 65% yield);. h nmr ( 500 mhz , cdcl3 )  7.587.65 
 ( m , 7h ) , 7.51 ( d , j = 8.3 hz , 2h ) , 7.364.42 
 ( m , 2h ) , 7.29 ( t , j = 7.3 hz , 1h ) , 3.79 ( q , j = 7.3 hz , 4h ) , 1.29 ( t , j = 7.3 hz , 6h ) , 
 1.01 ( s , 21h ) ; c nmr ( 125 mhz , cdcl3 )  
 150.6 , 144.0 , 140.0 , 139.1 , 137.7 , 133.7 , 129.7 , 129.2 , 128.4 , 127.5 , 
 126.8 , 126.4 , 122.0 , 120.8 , 106.4 , 94.1 , 18.6 , 11.3 ; ir ( cm ) 2940 , 2864 , 2361 , 2151 , 1463 , 1329 , 1233 , 1092 , 995 , 882 , 823 , 
 764 , 674 , 639 ; hrms ( esi ) m / z calcd 
 for c33h43n3sih ( [ m + h ] ) 510.3305 , found 510.3309 . compound 4a ( 0.096 
 g , 0.188 mmol , 1 equiv ) was dissolved in 2.5 ml of methyl iodide in 
 a sealable reaction flask , degassed , backfilled with nitrogen , sealed , 
 and heated to 125 c for 40 h. after cooling , the methyl iodide 
 was removed by evaporation and the product purified by flash chromatography 
 over neutral alumina with 50% methylene chloride in hexanes to afford 
 0.092 mg of the product as a yellow solid : mp 8183 c 
 ( 91% yield ) ; h nmr ( 500 mhz , cdcl3 )  
 7.77 ( d , j = 8.3 hz , 2h ) , 7.64 ( d , j = 8.3 hz , 2h ) , 7.61 ( d , j = 7.8 hz , 1h ) , 7.54 ( d , j = 8.3 hz , 2h ) , 7.277.38 ( m , 5h ) , 1.00 ( s , 21h ) ; c nmr ( 125 mhz , cdcl3 )  143.7 , 140.5 , 140.1 , 
 138.9 , 137.9 , 137.8 , 129.9 , 128.91 , 128.87 , 128.5 , 127.0 , 126.4 , 122.0 , 
 106.2 , 95.2 , 93.0 , 18.6 , 11.3 . ir ( cm ) 2939 , 2862 , 
 2152 , 1473 , 1384 , 1064 , 1000 , 882 , 837 , 812 , 578 , 662 ; hrms ( photospray 
 ionization ) m / z calcd for c29h33sii ( [ m ] ) 536.1396 , found 536.1383 . compound 18b ( 0.229 g , 0.427 
 mmol , 1.00 equiv ) was stirred with tbaf ( 1 m in thf ) ( 5.55 ml , 5.55 
 mmol , 13 equiv ) with 4 ml of thf and 1 ml of methanol for 3 days at 
 room temperature . the solvent was removed in vacuo , and the organic 
 products were extracted from water with methylene chloride . the combined 
 organic layers were dried over magnesium sulfate , filtered , and concentrated 
 to produce 0.127 g of an orange solid ( 78% yield ) : h nmr 
 ( 500 mhz , cdcl3 )  7.78 ( d , j = 8.6 hz , 2h ) , 7.68 ( d , j = 8.1 hz , 2h ) , 7.617.65 
 ( m , 3h ) , 7.387.43 ( m , 4h ) , 7.307.34 ( m , 1h ) , 3.08 
 ( s , 1h ) ; c nmr ( 125 mhz , cdcl3 )  143.7 , 
 140.2 , 139.6 , 139.1 , 137.8 , 134.0 , 129.7 , 129.5 , 129.0 , 128.9 , 127.1 , 
 126.4 , 120.3 , 93.1 , 83.0 , 80.4 ; hrms ( photospray ionization ) m / z calcd for c20h14i ( [ m + h ] ) 381.0140 , found 381.0151 compound 4a ( 0.240 
 g , 0.471 mmol , 1.00 equiv ) was stirred with tbaf ( 1 m in thf ) ( 1.41 
 ml , 1.41 mmol , 3.0 equiv ) with 2.0 ml of thf and 6 drops of methanol 
 for 40 h at room temperature . the organic products were extracted 
 from water with methylene chloride , dried over magnesium sulfate , 
 filtered , and concentrated in vacuo . purification over neutral alumina 
 with 50% methylene chloride in hexanes yielded 0.152 g of 1,1-diethyl-3-(4-(4-(2-ethynyl)phenyl)phenyl)phenyl)triaz-1-ene 
 as an orange solid : mp 117119 c ( 91% yield ) ; h nmr ( 500 mhz , cdcl3 )  7.567.68 ( m , 7h ) , 
 7.51 ( d , j = 8.3 hz , 2h ) , 7.40 ( m , 2h ) , 7.29 ( m , 
 1h ) , 3.77 ( q , j = 7.3 hz , 4h ) , 3.07 ( s , 1h ) , 1.26 
 ( br t , 6h ) ; c nmr ( 125 mhz , cdcl3 )  
 150.6 , 144.0 , 140.1 , 138.7 , 137.2 , 133.9 , 129.6 , 129.5 , 129.0 , 127.4 , 
 126.9 , 126.8 , 126.3 , 120.8 , 120.3 , 83.2 , 80.3 ; ir ( cm ) 3280 , 1471 , 1427 , 1324 , 1233 , 1098 , 1003 , 828 , 761 , 659 , 634 ; hrms 
 ( apci ) m / z calcd for c24h24n3 ( [ m ] ) 354.1970 , found 354.1965 . compounds 18b ( 0.100 g , 0.186 mmol , 1.00 equiv ) and 19b ( 0.069 g , 
 0.196 mmol , 1.05 equiv ) were dissolved with cui ( 0.001 g , 0.0056 mmol , 
 0.03 equiv ) and pdcl2(ph3p)2 ( 0.006 
 g , 0.009 mmol , 0.05 equiv ) in 0.5 ml of deoxygenated triethylamine 
 and 2.0 ml of deoxygenated thf . the reaction was stirred at room temperature , 
 periodically reloading solvent and palladium catalyst as needed over 
 the course of several days . when tlc failed to show any further conversion , 
 the solvents were removed in vacuo , and the products were extracted 
 from saturated ammonium chloride solution with methylene chloride . 
 the combined organic layers were dried over sodium sulfate , filtered , 
 and concentrated . flash chromatography over neutral alumina provided 
 0.108 g ( 76% yield ) of 20b as a yellow oil as well as 
 13% recovery of unreacted iodide 18b : h nmr 
 ( 500 mhz , cdcl3 )  7.77 ( d , j = 8.3 
 hz , 2h ) , 7.73 ( d , j = 8.3 hz , 2h ) , 7.517.69 
 ( m , 12h ) , 7.48 ( d , j = 7.8 hz , 1h ) , 7.337.45 
 ( m , 6h ) , 7.28 ( t , j = 7.3 hz , 1h ) , 3.78 ( q , j = 6.8 hz , 4h ) , 1.27 ( br t , 6h ) , 1.00 ( s , 21h ) ; c nmr ( 125 mhz , cdcl3 )  150.7 , 143.7 , 143.5 , 140.1 , 
 139.9 , 139.2 , 139.1 , 137.3 , 133.7 , 133.0 , 131.8 , 129.8 , 129.7 , 129.4 , 
 129.2 , 128.8 , 128.65 , 128.55 , 128.4 , 127.5 , 127.0 , 126.9 , 126.5 , 126.3 , 
 122.3 , 120.8 , 106.2 , 94.2 , 92.3 , 90.2 , 18.5 , 11.3 ; ir ( cm ) 3280 , 2978 , 2932 , 2360 , 1471 , 1427 , 1390 , 1322 , 1233 , 1098 , 828 , 
 761 , 698 , 659 ; hrms ( ei ) m / z calcd 
 for c53h55n3si ( [ m ] ) 
 761.4165 , found 761.4160 . compound 20b ( 0.096 g , 0.126 mmol , 1.00 equiv ) was dissolved in 2.5 ml of methyl 
 iodide in a sealable reaction flask , degassed , backfilled with nitrogen , 
 sealed , and heated to 125 c for 40 h. after cooling , the methyl 
 iodide was removed by evaporation and the product purified by flash 
 chromatography over silica with 25% methylene chloride in hexanes 
 to afford 0.065 mg of a white , crystalline solid : mp 109112 
 c ( 86% yield ) ; h nmr ( 500 mhz , cdcl3 ) 
  7.78 ( m , 4h ) , 7.517.69 ( m , 10h ) , 7.26746 ( m , 
 10h ) , 1.01 ( s , 21h ) ; c nmr ( 125 mhz , cdcl3 )  143.7 , 143.1 , 140.7 , 140.3 , 140.0 , 139.1 , 139.0 , 137.9 , 
 137.8 , 133.7 , 133.0 , 131.8 , 129.9 , 129.8 , 129.4 , 129.2 , 128.93 , 128.86 , 
 128.5 , 127.2 , 127.0 , 126.9 , 126.5 , 126.3 , 122.2 , 122.0 , 121.6 , 106.3 , 
 94.2 , 93.1 , 92.4 , 90.1 , 18.6 , 11.3 ; ir ( cm ) 2939 , 
 2861 , 2151 , 1473 , 1384 , 1064 , 1000 , 882 , 813 , 758 , 664 ; hrms m / z calcd for c37h38isi ( [ mh ] ) 637.1782 , found 637.1777 . compound 21b ( 0.086 g , 0.109 mmol , 1.00 equiv ) was dissolved in 0.5 ml of deoxygenated 
 thf and 0.2 ml of deoxygenated triethylamine with 19b ( 0.042 g , 0.120 mmol , 1.10 equiv ) , pdcl2(ph3p)2 ( 0.006 g , 0.0087 mmol , 0.08 equiv ) , and cui ( 0.0006 
 g , 0.0033 mmol , 0.03 equiv ) . the reaction was stirred at room temperature 
 for 24 h , the solvent was removed in vacuo , and the organic products 
 were extracted from saturated ammonium chloride solution with methylene 
 chloride . the combined organic layers were dried over sodium sulfate , 
 filtered , and concentrated . four rounds of purification by flash column 
 chromatography over alumina with 40% methylene chloride in hexanes 
 yielded 0.067 g of trimer 22b as a white , crystalline 
 solid : mp 167171 c ( 61% yield ) ; h nmr ( 500 
 mhz , cdcl3 )  7.227.79 ( m , 36h ) , 3.75 ( q , j = 7.3 hz , 4h ) , 1.25 ( br t , 6h ) , 1.00 ( s , 21h ) ; c nmr ( 125 mhz , cdcl3 )  150.6 , 143.6 , 143.4 , 143.1 , 
 140.8 , 140.6 , 140.3 , 140.2 , 140.1 , 139.8 , 139.3 , 139.1 , 139.0 , 137.3 , 
 133.6 , 133.1 , 133.0 , 132.9 , 131.8 , 131.7 , 129.8 , 129.7 , 129.4 , 129.1 , 
 128.7 , 128.5 , 128.4 , 127.5 , 127.4 , 127.1 , 127.0 , 126.8 , 126.4 , 126.2 , 
 122.4 , 122.3 , 122.2 , 121.9 , 121.5 , 120.8 , 106.2 , 94.1 , 92.3 , 92.3 , 
 90.3 , 90.2 , 90.0 , 18.5 , 11.2 ; ir ( cm ) 2929 , 2862 , 
 1474 , 1440 , 1343 , 1233 , 1091 , 1003 , 882 , 821 , 760 , 665 , 553 ; hrms 
 ( esi ) m / z calcd for c69h57n2si ( [ m  ( c4h10n ) ] ) 941.4291 , found 941.4255 . compound 22b ( 0.067 g , 0.066 mmol , 1.00 equiv ) was dissolved in 2.5 ml of methyl 
 iodide in a sealable reaction flask , degassed , backfilled with nitrogen , 
 sealed , and heated to 125 c for 40 h. after cooling , the methyl 
 iodide was removed by evaporation . the residue was filtered through 
 a silica plug with methylene chloride to provide 0.068 g of the product 
 iodide ( 99% yield ) as a colorless waxy solid , which was reacted without 
 further purification since poor solubility precluded further chromatography : h nmr ( 500 mhz , cdcl3 )  7.78 ( d , j = 8.8 hz , 6h ) , 7.527.70 ( m , 15h ) , 7.357.48 
 ( m , 14h ) , 7.29 ( m , 1h ) , 0.99 ( s , 21h ) ; c nmr ( 125 mhz , 
 cdcl3 )  143.7 , 143.1 , 140.7 , 140.5 , 140.3 , 139.9 , 
 139.2 , 139.1 , 139.0 , 137.9 , 133.7 , 133.0 , 131.8 , 131.7 , 129.9 , 129.9 , 
 129.8 , 129.4 , 128.9 , 128.6 , 127.2 , 126.9 , 126.8 , 126.4 , 126.4 , 126.3 , 
 122.3 , 122.2 , 122.0 , 121.5 , 106.2 , 94.1 , 93.1 , 92.3 , 90.1 , 18.6 , 11.3 ; 
 ir ( cm ) 2921 , 2860 , 2360 , 2342 , 2155 , 1473 , 1441 , 
 1384 , 1000 , 822 , 814 , 761 , 667 . compound 23b ( 0.070 g , 0.067 mmol , 1.00 equiv ) 
 was stirred with 4.0 
 ml of thf , 6 drops of methanol , and tbaf ( 1 m in thf ) ( 0.20 ml , 0.20 
 mmol , 3.0 equiv ) for 48 h , during which time a precipitate was observed 
 in the reaction . extraction from water with methylene chloride , drying 
 of the organic layers with magnesium sulfate , filtration , and concentration 
 in vacuo yielded 0.53 g of crude trimer ( 90% yield ) , which was used 
 in the next step without further purification or characterization . the crude linear iodoarylethyne trimer was dissolved in 10 ml of deoxygenated 
 thf and placed in a syringe pump . 1.5 equiv of pd(dba)2 ( 0.046 g , 0.080 mmol , 1.5 equiv ) , 1.3 equiv of cui ( 0.013 g , 0.068 
 mmol , 1.3 equiv ) , and 5.9 equiv of triphenylphosphine ( 0.082 g , 0.313 
 mmol , 5.9 equiv ) were dissolved in 5.0 ml of deoxygenated triethylamine 
 and 10 ml of deoxygenated thf . the catalyst solution was heated to 
 reflux under nitrogen , and the trimer solution was added at 0.6 ml / h , 
 followed by continued refluxing overnight . the solvents were then 
 removed in vacuo and the organic products extracted from saturated 
 ammonium chloride solution with methylene chloride , washed with water 
 and brine , and concentrated . the solids were then filtered with whatman 
 quantitative filter paper ( 1 m pore size ) and washed with methylene 
 chloride ; centrifugation in methylene chloride yielded 0.008 g ( 21% 
 yield ) of a colorless solid floating on top of the supernatant . no 
 melting transition was observed below 300 c : h nmr 
 ( 500 mhz , cdcl3 )  7.81 ( d , j = 8.3 
 hz , 2h ) , 7.70 ( d , j = 7.8 hz , 2h ) , 7.69 ( d , j = 6.3 hz , 1h)7.64 ( d , j = 8.3 hz , 2h ) , 
 7.52 ( d , j = 7.8 hz , 1h ) , 7.49 ( d , j = 7.8 hz , 2h ) , 7.44 ( t , j = 6.8 hz , 1h ) , 7.37 ( t , j = 7.3 hz , 1h ) ; h nmr ( 500 mhz , c6d4cl2 )  7.82 ( d , j = 8.0 hz , 6h ) , 7.70 ( d , j = 7.5 hz , 3h ) , 7.67 ( d , j = 8.0 hz , 6h ) , 7.58 ( d , j = 8.5 hz , 6h ) , 
 7.51 ( d , j = 8.5 hz , 6h ) , 7.47 ( d , j = 7.5 hz , 3h ) , 7.36 ( t , j = 7.3 hz , 3h ) , 7.29 ( t , j = 7.3 hz , 3h ) ; cosy ( 500 mhz , o - c6d4cl2 )  7.82  7.67 , 7.70 
  7.29 , 7.58  7.51 , 7.47  7.36 , 7.36  7.29 ; 
 hmqc ( 500 mhz , o - c6d4cl2 )  7.82  130.3 , 7.70  133.0 , 7.68  
 126.6 , 7.59  127.1 , 7.52  132.0 , 7.47  129.5 , 7.36 
  128.9 , 7.29  127.5 ; hmbc ( o-500 mhz , 
 c6d4cl2 , selected peaks )  
 7.82  143.3 , 7.82  139.5 , 7.70  143.3 , 7.70  
 90.7 , 7.68  140.4 , 7.68  139.8 , 7.59  139.5 , 7.59 
  122.6 , 7.52  140.4 , 7.52  92.7 , 7.47  139.8 , 
 7.47  121.6 , 7.36  143.3 , 7.29  121.6 ; ir ( cm ) 3056 , 3031 , 2217 , 1922 , 1498 , 1473 , 1442 , 1395 , 
 1104 , 1004 , 819 , 758 , 733 , 703 ; hrms ( maldi ) m / z calcd for c60h36 ( [ m ] ) 756.2817 , found 756.2822 . compound 17a ( 0.053 g , 0.139 mmol , 1.00 equiv ) was 
 dissolved in 0.8 
 ml of thf and 0.1 ml of triethylamine ( both solvents distilled and 
 deoxygenated ) with cui ( 0.3 mg , 0.0016 mmol , 0.01 equiv ) and pdcl2(ph3p)2 ( 0.005 g , 0.007 mmol , 0.05 equiv ) 
 and stirred at room temperature . the reaction was monitored by tlc 
 and periodically reloaded with catalysts and solvent until tlc failed 
 to indicate a significant change over a 24 h period . the solid precipitate 
 formed was filtered from solution and washed with methylene chloride 
 to yield a solid : h nmr ( 500 mhz , c6d4cl2 )  7.80 ( d ) , 7.267.7.2 ( m ) , 3.07 ( s ) . compound 17a ( 0.053 g , 0.139 mmol , 1.00 equiv ) was dissolved in 7.5 
 ml of thf and 0.1 ml of triethylamine ( both solvents were distilled 
 and deoxygenated ) with cui ( 0.3 mg , 0.0016 mmol , 0.01 equiv ) and pd(ph3p)4 ( 0.005 g , 0.007 mmol , 0.05 equiv ) and stirred 
 at room temperature . the reaction was monitored by tlc and periodically 
 reloaded with catalysts and solvent until tlc failed to indicate a 
 significant change over a 24 h period . the solid precipitate formed 
 was filtered from solution and washed with methylene chloride to yield 
 20% yield of macrocycle 2a with slight contamination 
 evidenced by : h nmr ( 500 mhz , cdcl3 )  
 7.78 ( d , j = 7.8 hz ) , 7.62 ( d , j = 7.8 hz ) . [ bnn(ch3)3]icl2 ( 3.535 g , 
 10.15 mmol , 1.05 equiv ) and caco3 ( 3.141 g , 31.38 mmol , 
 3.21 equiv ) were added to a stirred solution of 4-n - octylaniline ( 1.995 g , 9.72 mmol , 1 equiv ) in 80 ml of dry ch2cl2 and 35 ml of anhydrous meoh . the reaction stirred 
 at room temperature for 2 h prior to being vacuum filtered through 
 a pad of celite . the filtrate was washed with satd na2so4 ( 40 ml ) followed by satd nh4cl ( 40 ml ) . the organics 
 were dried over mgso4 , filtered , and concentrated in vacuo 
 to give a brown oil that was purified by chromatography ( 10% ethyl 
 acetate in hexane on silica ) to give 3.08 g of a brown oil ( 96% yield ) . this product was used in subsequent reactions without further purification : h nmr ( 500 mhz , cdcl3 )  7.43 ( d , j = 1.9 hz , 1h ) , 6.93 ( dd , j = 1.9 , 8.3 
 hz , 1h ) , 6.65 ( d , j = 8.3 hz , 1h ) , 3.93 ( br s , 2h ) , 
 2.44 ( t , j = 7.3 hz , 2h ) , 1.52 ( m , 2h ) , 1.231.31 
 ( m , 10h ) , 0.88 ( t , j = 7.3 hz , 3h ) ; c nmr ( 125 mhz , cdcl3 )  144.4 , 138.4 , 134.8 , 129.4 , 
 114.6 , 84.4 , 34.5 , 31.8 , 31.6 , 29.5 , 29.4 , 29.2 , 22.6 , 14.0 ; ir ( cm ) 3407 , 3317 , 2954 , 2916 , 2850 , 1617 , 1496 , 1467 , 
 1405 , 1306 , 1152 , 1028 , 819 , 665 ; hrms ( maldi ) m / z calcd for c14h22ni ( [ m + h ] ) 332.0870 , found 332.0870 . hcl ( 1.1 ml , 13.2 mmol , 7.8 equiv ) was 
 added dropwise 
 to a solution of 11 ( 0.558 g , 1.68 mmol , 1 equiv ) in 
 10.0 ml of tetrahydrofuran and 0.6 ml of acetonitrile chilled to 5 
 c in an ice  salt bath . a solution of nano2 ( 0.415 g , 6.02 mmol , 3.58 equiv ) in 1.8 ml of water and 0.8 ml acetonitrile 
 was added dropwise , and the reaction was stirred at 5 c 
 for 30 min before being slowly transferred via cannula to a flask 
 containing diethylamine ( 3.5 ml , 42.5 mmol , 25 equiv ) and k2co3 ( 2.32 g , 16.8 mmol , 10 equiv ) in 7.0 ml of water at 
 0 c . the reaction was stirred for 45 min while warming to room 
 temperature before being diluted with satd nacl and extracted with 
 et2o . the organics were washed with h2o , dried 
 over mgso4 , filtered , and concentrated in vacuo . crude 
 material was purified by flash chromatography using hexanes to afford 
 0.686 g of an orange oil ( 98% yield ) : h nmr ( 500 mhz , 
 cdcl3 )  7.66 ( d , j = 1.9 hz , 1h ) , 
 7.25 ( d , j = 8.6 hz , 1h ) , 7.08 ( dd , j = 1.9 , 8.2 hz , 1h ) , 3.78 ( q , j = 7.2 hz , 4h ) , 2.52 
 ( t , j = 7.5 hz , 2h ) , 1.57 ( m , 2h ) , 1.231.33 
 ( m , 12h ) , 0.88 ( t , j = 6.4 hz , 3h ) ; c nmr ( 125 mhz , cdcl3 )  148.3 , 141.5 , 138.6 , 128.8 , 
 117.1 , 96.5 , 34.9 , 31.8 , 31.4 , 29.4 , 29.22 , 29.16 , 22.6 , 14.1 ; ir 
 ( cm ) 2923 , 2853 , 1463 , 1432 , 1389 , 1331 , 1266 , 
 1234 , 1202 , 1105 ; hrms ( maldi ) m / z calcd for c18h30n3i ( [ m + h ] ) 416.1563 , found 416.1558 . compound 12 ( 0.250 
 g , 0.602 mmol , 1.00 equiv ) , ( triisopropylsilyl)acetylene ( 0.21 ml , 
 0.934 mmol , 1.55 equiv ) , cl2pd(pph3)2 ( 0.0227 g , 0.0323 mmol , 0.054 equiv ) , and cui ( 0.0039 g , 0.0204 
 mmol , 0.034 equiv ) were combined in a 50 ml round - bottomed flask and 
 purged with n2 . ten milliliters of deoxygenated thf and 
 10 ml of deoxygenated et3n were added by syringe , and the 
 reaction was stirred at 40 c for 18 h. the reaction mixture 
 was then diluted with h2o ( 50 ml ) and extracted with etoac 
 ( 3  50 ml ) . the combined organic phases were washed with satd 
 nh4cl ( 2  50 ml ) , dried over mgso4 , filtered , 
 and concentrated in vacuo . the crude material was purified by flash 
 chromatography using 5% et2o in hexanes to give 0.256 g 
 of a brown / orange oil ( 92% yield ) : h nmr ( 500 mhz , cdcl3 )  7.34 ( d , j = 8.3 hz , 1h ) , 7.28 
 ( d , j = 1.9 hz , 1h ) , 3.77 ( q , j = 7.3 hz , 4h ) , 2.53 ( t , j = 7.3 hz , 2h ) , 1.551.60 
 ( m , 2h ) , 1.221.32 ( m , 18h ) , 1.13 ( s , 21h ) , 0.88 ( t , j = 6.3 hz , 3h ) ; c nmr ( 125 mhz , cdcl3 )  150.5 , 139.2 , 133.5 , 129.2 , 118.2 , 116.5 , 105.9 , 35.2 , 
 31.9 , 31.5 , 29.5 , 29.2 , 22.7 , 18.8 , 14.1 , 11.4 ; ir ( cm ) 2925 , 2862 , 2147 , 1463 , 1398 , 1330 , 1242 , 1201 , 1092 , 883 ; hrms 
 ( maldi ) m / z calcd for c29h51n3si ( [ m + h ] ) 470.3930 , found 
 470.3917 . compound 13 ( 0.485 
 g , 1.032 
 mmol , 1 equiv ) was dissolved in 5 ml of mei in a sealed tube . the 
 reaction flask was evacuated and backfilled with n2 before 
 being sealed and heated to 125 c for 20 h. the reaction was 
 cooled to room temperature before excess mei was evaporated by n2 bubbling . the crude residue was purified by flash chromatography 
 using hexanes as eluent to afford 0.51 g of a yellow oil ( 99% yield ) : h nmr ( 500 mhz , cdcl3 )  7.70 ( d , j = 8.2 hz , 1h ) , 7.29 ( d , j = 2.1 hz , 1h ) , 
 6.81 ( dd , j = 2.1 , 8.0 hz , 1h ) , 2.51 ( t , j = 7.7 hz , 2h ) , 1.231.31 ( m , 10h ) , 1.16 ( s , 21h ) , 
 0.88 ( t , j = 7.1 , 3h ) ; c nmr ( 125 mhz , 
 cdcl3 )  142.8 , 138.4 , 133.2 , 129.9 , 129.8 , 108.2 , 
 97.1 , 94.6 , 31.9 , 31.2 , 29.4 , 29.2 , 22.6 , 18.7 , 14.1 , 11.4 ; ir ( cm ) 2923 , 2862 , 2366 , 2150 , 1459 , 1394 , 1017 , 883 , 765 , 
 735 , 665 ; hrms ( maldi ) m / z calcd 
 for c25h41isi ( [ m + h ] ) 497.2100 , 
 found 497.2098 . boronic ester 6 ( 0.620 g , 
 2.04 mmol , 2.00 equiv ) and 14 ( 0.508 g , 1.02 mmol , 1.00 
 equiv ) were dissolved in deoxygenated dme and further deoxygenated 
 for 10 min by n2 bubbling . to this solution were added 
 cl2pd(dppf ) ( 0.061 g , 0.0834 mmol , 0.082 equiv ) and dry 
 k3po4 ( 1.045 g , 4.922 mmol , 4.83 equiv ) , and 
 the reaction was deoxygenated by n2 bubbling for an additional 
 10 min . the reaction was heated to 90 c for 20 h before being 
 cooled to room temperature and diluted with h2o . the reaction 
 was extracted with et2o ( 3  30 ml ) , and organics 
 were washed with satd nacl before being dried over mgso4 , filtered , and concentrated in vacuo . purification by flash chromatography 
 over neutral alumina with 5% diethyl ether in hexanes gave 0.56 g 
 of a yellow oil ( 82% yield ) : h nmr ( 500 mhz , cdcl3 )  7.58 ( d , j = 8.3 hz , 2h ) , 7.41 
 ( d , j = 8.8 hz , 3h ) , 7.29 ( d , j = 7.8 hz , 1h ) , 7.16 ( d , j = 7.8 hz , 1h ) , 3.77 ( q , j = 7.0 hz , 4h ) , 2.60 ( t , j = 7.8 hz , 2h ) , 
 1.64 ( m , 2h ) , 1.251.38 ( m , 16 h ) , 1.03 ( s , 21h ) , 0.88 ( t , j = 6.8 hz , 3h ) ; c nmr ( 125 mhz , cdcl3 )  150.3 , 141.5 , 141.3 , 137.2 , 133.7 , 129.8 , 129.2 , 128.8 , 
 121.5 , 119.9 , 106.9 , 93.2 , 35.3 , 31.9 , 31.4 , 29.5 , 29.4 , 29.3 , 22.7 , 
 18.7 , 14.1 , 11.3 ; ir ( cm ) 2926 , 2862 , 2363 , 2341 , 
 2146 , 1463 , 1380 , 1234 , 1095 , 908 , 883 , 827 , 734 , 666 ; hrms ( esi ) m / z calcd for c35h55n3sih ( [ m + h ] ) 546.4244 , found 546.4235 . compound 3b ( 0.349 
 g , 0.639 mmol , 1.00 equiv ) was dissolved in 5 ml of mei in a sealed 
 tube . the flask was evacuated and purged with n2 before 
 being sealed and heated to 125 c for 44 h. the reaction was 
 cooled to room temperature before excess mei was removed by n2 bubbling . the crude residue was purified by flash chromatography 
 using 5% et2o in hexanes to afford 0.336 g of the desired 
 compound as a colorless oil ( 92% yield ) : h nmr ( 500 mhz , 
 cdcl3 )  7.69 ( d , j = 8.3 hz , 2h ) , 
 7.39 ( s , 1h ) , 7.30 ( d , j = 8.8 hz , 2h ) , 7.21 ( d , j = 7.8 hz , 1h ) , 7.17 ( dd , j = 7.8 , 1.5 
 hz , 1h ) , 2.60 ( t , j = 7.8 hz , 2h ) , 1.63 ( m , 2h ) , 
 1.251.37 ( m , 10h ) , 1.01 ( s , 21h ) , 0.88 ( t , j = 7.3 hz , 3h ) ; c nmr ( 125 mhz , cdcl3 )  
 142.3 , 140.5 , 140.1 , 136.9 , 133.5 , 131.3 , 128.9 , 128.8 , 106.2 , 93.9 , 
 92.8 , 35.4 , 31.9 , 31.4 , 29.4 , 29.3 , 29.2 , 22.7 , 18.6 , 14.1 , 11.3 ; 
 ir ( cm ) 2924 , 2861 , 2366 , 2333 , 2145 , 1464 , 1385 , 
 1000 , 883 , 816 , 667 ; hrms ( esi ) m / z calcd for c31h45sii ( [ m ] ) 572.2335 , 
 found 572.2344 . compound 15 ( 0.299 
 g , 0.522 mmol , 1.00 
 equiv ) was dissolved in 2 ml of thf before 0.63 ml of 1 m tbaf ( in 
 thf containing 5% h2o ) was added . the reaction was then concentrated , 
 and the residue was dissolved in et2o and washed with satd 
 nh4cl . the organic phase was dried over mgso4 , filtered , and concentrated in vacuo . the crude material was purified 
 by flash chromatography using hexanes to afford 0.22 g of a colorless 
 oil ( 74% yield ) : h nmr : ( cdcl3 , 500 mhz )  
 7.90 ( d , j = 7.0 hz , 2h ) , 7.49 ( s , 1h ) , 7.37 ( d , j = 7.0 hz , 2h ) , 7.287.24 ( m , 2h ) , 3.07 ( s , 1h ) , 
 2.64 ( t , j = 7.8 hz , 2h ) , 1.68 ( m , 2h ) , 1.251.37 
 ( m , 10h ) , 0.88 ( t , j = 7.3 hz , 3h ) ; c nmr ( cdcl3 , 125 mhz )  142.3 , 140.6 , 139.7 , 137.1 , 
 133.9 , 131.1 , 129.4 , 129.2 , 120.0 , 93.4 , 83.2 , 80.2 , 77.1 , 35.3 , 31.9 , 
 31.2 , 29.5 , 29.3 , 29.2 , 22.7 , 14.2 ; ir ( neat , cm ) 3293 , 1479.7 , 1384 , 1007 , 814 ; hrms ( esi ) m / z calcd for c22h25ih ( [ m + h ] ) 417.1071 , found 417.1090 . compound 16b ( 0.031 g , 0.074 mmol , 1.00 equiv ) was dissolved in 2.6 
 ml of 1:1 phch3/et3n . cl2pd(pph3)2 ( 0.002 g , 0.0028 mmol , 0.038 equiv ) and cui 
 ( 0.001 g , 0.005 mmol , 0.07 equiv ) were added neat . the reaction was 
 stirred at room temperature for 2 h and monitored by tlc ( 10% etoac 
 in hexanes ) . it was then diluted with h2o and extracted 
 with et2o ( 3  20 ml ) , and the combined organic phases 
 were washed with satd nacl before being dried over mgso4 , filtered , and concentrated in vacuo . purification required 5 
 silica gel flash columns using 5% ch2cl2 in 
 hexanes to afford 2.5 mg of the cyclotrimer 1b and 1.2 
 mg of the cyclotetramer 1c , both as white waxy solids 
 ( 12% and 6% yield , respectively ) . cyclic trimer 1b : h nmr ( cdcl3 , 500 mhz )  7.73 ( d , j = 6.5 hz , 6h ) , 7.48 ( s , 3h ) , 7.47 ( d , j = 8.0 hz , 6h ) , 7.39 ( d , j = 8.5 hz , 3h ) , 7.23 ( d , j = 8.0 hz , 3h ) , 2.65 ( t , j = 7.7 hz , 6h ) , 
 1.67 ( quintet , j = 7.5 hz , 6h ) , 1.401.26 
 ( m , 30h ) , 0.89 ( t , j = 6.5 hz , 9h ) ; c nmr ( 125 mhz , cdcl3 )  140.55 , 140.24 , 137.32 , 
 132.75 , 130.87 , 129.42 , 129.35 , 129.20 , 122.35 , 121.33 , 92.48 , 90.02 , 
 35.56 , 32.06 , 31.46 , 29.64 , 29.49 , 29.42 , 22.84 , 14.27 ; hrms ( maldi ) m / z calcd for c66h72 ( [ m ] ) 864.5634 , found 864.5624 . cyclic tetramer 1c : h nmr ( cdcl3 , 500 mhz )  
 7.65 ( d , j = 8.5 hz , 6h ) , 7.49 
 ( d , j = 1.5 hz , 3h ) , 7.45 ( d , j = 
 8.5 hz , 6h ) , 7.31 ( d , j = 8.5 hz , 3h ) , 7.20 ( dd , j = 8.0 hz , 1.5 hz , 3h ) , 2.64 ( t , j = 7.5 
 hz , 3h ) , 1.67 ( quintet , j = 7.0 hz , 6h ) 1.401.26 
 ( m , 30h ) , 0.88 ( t , j = 7.0 hz , 9h ) ; c nmr ( 125 mhz , cdcl3 )  140.56 , 137.14 , 133.21 , 
 131.40 , 129.68 , 129.47 , 129.25 , 122.39 , 121.35 , 92.20 , 89.88 , 35.56 , 
 32.05 , 31.44 , 29.63 , 29.52 , 29.41 , 22.83 , 14.27 ; hrms ( maldi ) m / z calcd for c88h96 ( [ m ] ) 1152.75065 , found 1152.7470 . compound 15 ( 0.276 
 g , 0.482 mmol , 1.00 equiv ) was added to a round - bottomed flask fitted 
 with a sealed reflux condenser , as were 6 ( 0.248 g , 0.819 
 mmol , 1.7 equiv ) , tribasic potassium phosphate ( 0.563 g , 2.65 mmol , 
 5.5 equiv ) , and pdcl2(dppf ) ( 0.018 g , 0.022 mmol , 0.045 
 equiv ) . the flask was purged with nitrogen and 4.0 ml deoxygenated 
 1,2-dimethoxyethane added . the reaction was heated to reflux for 5 
 h and cooled to room temperature and the solvent removed under vacuum . the product was extracted from water with ether , and the combined 
 organic layers washed with brine , dried over magnesium sulfate , filtered , 
 and concentrated . purification by flash column chromatography over 
 neutral alumina with 25% methylene chloride in hexanes afforded 0.204 
 g of a dark yellow oil ( 68% yield ) : h nmr ( 500 mhz , cdcl3 )  7.63 ( d , j = 8.4 hz , 2h ) , 7.577.61 
 ( m , 4h ) , 7.50 ( d , j = 8.8 hz , 2h ) , 7.42 ( d , j = 1.5 hz , 1h ) , 7.31 ( d , j = 8.0 hz , 1h ) , 
 7.19 ( dd , j = 1.7 , 7.7 hz , 1h ) , 3.78 ( q , j = 7.1 hz , 4h ) , 2.61 ( t , j = 7.7 hz , 2h ) , 
 1.65 ( m , 2h ) , 1.251.38 ( m , 16h ) , 1.01 ( s , 21h ) , 0.89 ( t , j = 6.9 hz , 3h ) ; c nmr ( 125 mhz , cdcl3 )  150.5 , 141.7 , 141.4 , 139.8 , 139.1 , 137.7 , 133.5 , 129.6 , 
 129.1 , 128.7 , 127.3 , 126.3 , 121.7 , 120.7 , 106.7 , 93.4 , 35.4 , 31.9 , 
 31.4 , 29.5 , 29.4 , 29.3 , 22.6 , 18.6 , 14.1 , 11.3 ; ir ( cm ) 2926 , 2864 , 2146 , 1462 , 1396 , 1352 , 1235 , 1100 , 882 , 818 , 770 , 
 663 ; hrms ( esi ) m / z calcd for c37h49n2si ( [ m  ( c4h10n ) ] ) 549.3665 , found 549.3659 . compound 4b ( 0.0631 
 g , 0.101 mmol , 1.00 equiv ) was added to 2.5 ml of iodomethane in a 
 flask fitted with a sealable valve and the flask degassed and backfilled 
 with nitrogen . the flask was sealed and the reaction heated to 125 
 c for 44 h. after cooling , the methyl iodide was evaporated 
 and the product filtered through a silica plug with 25% dichloromethane 
 in hexanes to afford 0.065 g ( quantitative yield ) of the iodide as 
 a reddish oil : h nmr ( 500 mhz , cdcl3 )  
 7.77 ( d , j = 8.3 hz , 2h ) , 7.64 ( d , j = 8.3 hz , 2h ) , 7.53 ( d , j = 8.3 hz , 2h ) , 7.42 ( d , j = 1.4 hz , 1h ) , 7.33 ( d , j = 8.3 hz , 2h ) , 
 7.29 ( d , j = 7.8 hz , 1h ) , 7.19 ( dd , j = 1.4 , 7.8 hz , 1h ) , 2.60 ( t , j = 7.8 hz , 2h ) , 1.65 
 ( m , 2h ) , 1.251.39 ( m , 10h ) , 1.00 ( s , 21h ) , 0.89 ( t , j = 6.9 hz , 3h ) ; c nmr ( 125 mhz , cdcl3 )  141.9 , 141.1 , 140.6 , 140.1 , 138.6 , 137.8 , 133.5 , 129.8 , 
 129.1 , 128.9 , 128.8 , 126.3 , 121.7 , 106.6 , 93.5 , 92.8 , 35.3 , 31.8 , 
 31.3 , 29.4 , 29.3 , 29.2 , 22.6 , 18.5 , 14.0 , 11.3 ; ir ( cm ) 2923 , 2861 , 2363 , 2148 , 1476 , 1382 , 1064 , 1000 , 882 , 810 , 771 , 
 734 , 666 ; hrms ( ei ) m / z calcd for 
 c37h50isi ( [ m + h ] ) 649.2726 , found 
 649.2714 . 2-(2-triisopropylsilyl)ethynyl-4-octyl-4-iodoterphenyl 
 ( 0.0519 g , 0.080 mmol , 1.00 equiv ) was dissolved in 2 ml of thf with 
 5 drops of methanol , to which tbaf ( 1 m in thf ) ( 1.05 ml , 1.05 mmol , 
 13 equiv ) was added . the reaction was stirred overnight at room temperature , 
 and the solvents were evaporated . the crude product was purified by 
 column chromatography over silica with 100% hexanes followed by 25% 
 dichloromethane in hexanes to yield 0.039 g of white crystals : mp 
 6971 c ( 98% yield ) ; h nmr ( 500 mhz , cdcl3 )  7.76 ( d , j = 8.6 hz , 2h ) , 7.66 
 ( d , j = 8.6 hz , 2h ) , 7.60 ( d , j = 8.4 hz , 2h ) , 7.46 ( d , j = 1.7 hz , 1h ) , 7.38 ( d , j = 8.4 hz , 2h ) , 7.31 ( d , j = 8.0 hz , 1h ) , 
 7.23 ( dd , j = 1.9 , 8.0 hz , 1h ) , 3.04 ( s , 1h ) , 2.62 
 ( t , j = 7.7 hz , 2h ) , 1.65 ( m , 2h ) , 1.251.37 
 ( m , 10h ) , 0.89 ( t , j = 7.1 hz , 3h ) ; c nmr ( 125 mhz , cdcl3 )  142.0 , 141.0 , 139.6 , 138.8 , 
 137.8 , 133.8 , 129.7 , 129.3 , 128.9 , 126.4 , 120.0 , 93.0 , 83.4 , 79.8 , 
 35.3 , 31.8 , 31.2 , 29.4 , 29.2 , 29.2 , 22.6 , 14.0 ; ir ( cm ) 3288 , 2922 , 2854 , 2360 , 2340 , 1478 , 1386 , 1000 , 895 , 808 , 788 , 
 731 , 657 , 611 ; hrms ( ei ) m / z calcd 
 for c28h29i ( [ m ] ) 492.1314 , found 
 492.1312 . compound 17b ( 0.0364 g , 0.074 mmol , 1.00 equiv ) was dissolved with 
 cui ( 0.0009 g , 0.0047 mmol , 0.06 equiv ) and pd(ph3p)4 ( 0.0243 g , 0.021 mmol , 0.28 equiv ) in 40 ml of dry , deoxygenated 
 thf and 10 ml of triethylamine . the reaction was stirred at room temperature 
 under nitrogen for 2 weeks , with periodic reloading of catalyst ( only 
 3 mol % of pd at a time ) . when tlc indicated the reaction had gone 
 to completion , the solvents were removed in vacuo , and the reaction 
 was purified over a silica column with 15% dichloromethane in hexanes . two products were recovered , 3.2 mg of cyclodimer 2c ( 12% 
 yield ) and 13.8 mg of cyclotrimer 2b ( 51% yield ) , both 
 as colorless waxy solids . 2c : h nmr 
 ( 500 mhz , cdcl3 )  7.75 ( d , j = 
 8.3 hz , 4h ) , 7.67 ( d , j = 8.3 hz , 4h ) , 7.60 ( d , j = 8.3 hz , 4h ) , 7.51 ( d , j = 1.5 hz , 
 2h ) , 7.41 ( d , j = 8.3 hz , 4h ) , 7.37 ( d , j = 7.8 hz , 2h ) , 7.22 ( dd , j = 7.8 , 1.5 
 hz , 2h ) , 2.66 ( t , j = 7.8 hz , 4h ) , 1.68 ( quintet , j = 6.8 hz , 4h ) , 1.271.41 ( m , 20 h ) , 0.89 ( t , j 
 = 6.8 hz , 6h ) ; cosy ( 500 mhz , cdcl3 )  7.75  
 7.67 , 7.60  7.41 , 7.37  7.22 , 2.66  1.68 , 1.68  
 1.38 , 1.30  0.89 ; hmqc ( cdcl3 )  7.75  
 130.0 , 7.67  126.3 , 7.60  126.9 , 7.51  132.6 , 7.41 
  131.8 , 7.37  129.3 , 7.22  129.0 , 2.66  35.5 , 
 1.68  31.3 , 1.36  29.4 , 1.31  22.6 , 1.26  
 31.8 , 1.22  26.7 , 1.21  33.5 , 0.89  14.1 ; maldi - tof 
 ( dhb matrix ) [ m ] m / z calcd for c56h56 728.4832 , found 728.6150 . 2b : h nmr ( 500 mhz , cdcl3 ) 
  7.80 ( d , j = 8.3 hz , 6h ) , 7.68 ( d , j = 8.3 hz , 6h ) , 7.64 ( d , j = 7.8 hz , 
 6h ) , 7.52 ( s , 3h ) , 7.49 ( d , j = 7.8 hz , 6h ) , 7.42 
 ( d , j = 7.8 hz , 3h ) , 7.26 ( m , 3h ) , 2.67 ( t , j = 7.8 hz , 6h ) , 1.69 ( quintet , j = 8.3 
 hz , 6h ) , 1.291.42 ( m , 30h ) , 0.90 ( quintet , j = 8.3 hz , 9h ) ; c nmr ( 125 mhz , cdcl3 )  
 142.1 , 140.7 , 140.6 , 139.8 , 139.3 , 132.6 , 131.7 , 130.0 , 129.2 , 127.1 , 
 126.4 , 122.5 , 121.2 , 91.8 , 90.5 , 35.4 , 31.9 , 31.3 , 29.7 , 29.5 , 29.3 , 
 22.7 , 14.1 ; hmqc ( cdcl3 )  7.80  130.1 , 7.68 
  126.4 , 7.64  127.1 , 7.49  131.7 , 7.52  132.6 , 
 7.42  129.2 , 7.26  129.9 , 2.67  35.4 , 1.69  
 31.3 , 1.36  29.5 , 1.29  22.7 , 0.89  14.1 ; hmbc ( cdcl3 , selected peaks )  7.80  140.7 , 7.80  139.3 , 
 7.68  140.6 , 7.68  139.8 , 7.64  139.3 , 7.64  
 122.5 , 7.52  90.5 , 7.52  35.4 , 7.49  140.7 , 7.49 
  91.8 , 7.42  142.1 , 7.42  139.8 , 7.42  121.2 , 
 7.26  140.6 , 2.67  129.2 , 2.67  132.6 , 2.67  
 142.1 , 2.67  31.3 , 2.67  29.3 , 1.69  29.3 , 1.36 
  29.7 , 0.90  31.9 , 0.90  22.7 ; maldi - tof ( dhb matrix ) m / z calcd for c84h84 ( [ m ] ) 1092.7 , found 1092.7 . hrms ( maldi ) m / z calcd for c84h84 ( [ m ] ) 1092.6573 , found 1092.6612 .
a series 
 of single - walled carbon nanotube precursors , c3h - symmetric cyclotri(ethynylene)(biphenyl-2,4-diyl ) 
 and cyclotri(ethynylene)(p - terphenyl-2,4-diyl ) , 
 have been prepared by a linear stepwise oligomerization 
 cyclization 
 route and by statistical intermolecular cyclooligomerization . 
 in addition 
 to producing these members of a novel class of arylene ethynylene 
 macrocycles , 1 and 2 , the latter statistical 
 process produces the smaller cyclic dimer , cyclodi(ethynylene)(p - terphenyl-2,4-diyl ) and the larger cyclic tetramer 
 cyclotetra(ethynylene)(biphenyl-2,4-diyl ) . 
 these macrocycles 
 display large stokes shifts in their fluorescence spectra . 
 their biphenyl 
 or terphenyl connectivity prevents these macrocycles from achieving 
 full planarity in the ground state , and the ethynylene moieties could 
 provide synthetic access to cyclic arylene oligomers and discrete 
 carbon nanotube segments .