4,4-difluoro-4-bora-3a,4a - diaza - s - indacene ( known 
 as bodipy ) is a class of very versatile fluorophores that has been 
 widely recognized and exploited in the last several decades . these 
 dyes have found various applications as labeling agents , chemical 
 sensors , photosensitizers , and energy - related cassettes and in luminescent 
 devices . bodipy dyes have advantages compared with other fluorophores , including 
 large molar absorption coefficients and high fluorescence quantum 
 yields , redox active , relatively high thermal and photochemical stability , 
 and easy functionalization that enables the tuning of their properties , 
 such as absorption / emission wavelengths , charge - transfer , and amphiphilicity . due in part to their relatively low molecular weight , bodipys and their conjugates usually show good permeability across the membranes 
 of living cells , making them suitable for biological and medical applications . various methods have been developed for the functionalization 
 of 
 bodipys to change their photophysical , hydrophobic , and charge - transfer 
 properties . these methods include , but are not limited to , electrophilic 
 and nucleophilic substitutions , palladium - catalyzed cross - couplings , 
 aromatic ring fusion , and knoevenagel condensations . among these , aromatic ring fusion and cross - coupling reactions are particularly useful for inducing 
 bathochromic shifts of the bodipy optical transitions via extension 
 of -conjugation , while substitution reactions are often used to modify the molecular amphiphilicity upon introduction 
 of heteroatom - based groups , and for bioconjugations . halogenated bodipys 
 are particularly versatile substrates for functionalization purposes 
 via both cross - coupling and nucleophilic substitution reactions , and 
 all halogens ( fluoride , chloride , bromide , and iodide ) have been introduced 
 into the pyrrolic positions of bodipy ( or a dipyrromethane or pyrrole 
 precursor ) , mainly using electrophilic substitution . in particular , functionalization of the bodipy core 
 at the 3,5-positions significantly affects the spectroscopic and photophysical 
 properties , and this strategy has been exploited for the synthesis 
 of a variety of functionalized bodipys , from 3,5-dichloro- or 3,5-diiodo - bodipy 
 precursors . on the other hand , a very useful method for facile transformation 
 of dipyrroketones into 5-chlorodipyrromethene salts using phosgene was developed by fischer and orth and 
 has since been exploited by others and ourselves . the resulting 8-chloro - bodipys are reactive 
 toward palladium - catalyzed cross - coupling reactions and to nucleophilic 
 aromatic substitutions using n- , o- , and s - based nucleophiles . palladium - catalyzed 
 suzuki , stille , sonogashira , and heck cross - coupling reactions have 
 all been performed on 3,5-chloro - bodipy , while suzuki , stille , and 
 sonogashira reactions have been achieved at the 8-position . among 
 these , the milder stille reaction conditions , using pd(pph3)4 and a organotin reagent in toluene , in the absence 
 of a base , gave 8-aryl , -alkyl , and -ethynyl - bodipys in yields > 93% , making it a highly efficient methodology for 
 the functionalization of chloro - bodipys . herein we report the synthesis 
 of a symmetrical 3,5,8-trichloro - bodipy ( 5 ) and describe 
 both its global and regioselective functionalization using stille 
 coupling reactions to afford both symmetric and unsymmetric bodipy 
 dyes with extended -conjugated systems . the spectroscopic properties 
 of the 19 new bodipy derivatives synthesized and structurally characterized , 
 including 14 x - ray structures , are compared and discussed . 3,5,8-trichloro - bodipy 5 , bearing 
 two methyl propanoate groups that could subsequently be used for bioconjugation , 
 was prepared as shown in scheme 1 . symmetrical 
 dipyrromethane 1 was obtained by treatment of benzyl 
 4-(2-methoxycarbonylethyl)-3,5-dimethylpyrrole-2-carboxylate on a 
 1020 g scale with 1 equiv of bromine in diethyl ether , followed 
 by heating in methanol . it was then oxidized with pb(oac)4/pbo2 in acetic acid to give 
 the corresponding dipyrrylketone 2 in 60% yield . unlike 
 our previously reported tetra- and hexaalkyldipyrrylketones , the electron - deficient dipyrrylketone 2 therefore , dipyrrylketone 2 was subjected instead to palladium - catalyzed debenzylation 
 in a hydrogen atmosphere , followed by decarboxylative iodination to 
 provide the 3,5-diiododipyrrylketone 3 in 69% overall 
 yield . upon treatment with excess phosgene , the 3,5-diiododipyrrylketone 3 was converted into the 
 fully conjugated meso - chlorodipyrromethene hydrochloride 4 which was not isolated but immediately complexed with bf3et2o in situ under basic conditions , to afford 
 bodipy 5 as the major product in 55% yield from 3 . bodipys 6 and 7 were also isolated 
 as minor byproducts , obtained in 11% and 5% yields from 3 , respectively , after chromatographic separation . the trans - halogenation 
 of 3,5-diiododipyrrylketone 3 to give 4 is 
 probably a result of nucleophilic addition / elimination by chloride 
 during the process , as nucleophilic substitutions at the 3,5- and 
 8-positions of the bodipy have been shown to occur in the presence 
 of a variety of nucleophiles . on the other hand , byproducts 6 and 7 likely 
 resulted from dehalogenation of the 3- and 3,5-positions , respectively , 
 under the reaction conditions . the structures of bodipys 5 and 7 were unequivocally identified by their x - ray 
 structures , shown in figure 1 . reaction conditions : ( i ) br2 , et2o ; ( ii ) meoh ,  ( 70% yield , two steps ) ; 
 ( iii ) pb(oac)4/pbo2 , ( 60% ) ; ( iv ) pd / c , h2 , thf , ( 92% ) ; ( v ) i2 , nahco3 , meoh / h2o , ( 75% ) ; ( vi ) cocl2 ( toluene soln ) ; ( vii ) bf3et2o , diea , ( 5 , 55% ) , ( 6 , 11% ) , ( 7 , 5% ) . x - ray structures 
 of bodipys 5 and 7 , 
 with 50% ellipsoids . both molecules have essentially c2 symmetry , 
 with 7 lying on a crystallographic 2-fold axis , and 5 having nearly the same conformation . the torsion angle about 
 the ch2ch2 bonds of the methyl propanoate 
 substituents is 66.1 in 7 , while in 5 , the two torsion angles differ by 21.2 , but their 
 mean value , 66.2 , closely matches that in 7 . the central c3n2b ring is slightly more twisted 
 in 5 , with n atoms lying 0.11  out of the 
 c3b plane , compared to 0.05  in 7 . the n2b and bf2 planes form a dihedral angle 
 of 89.2 in 5 and 89.9 in 7 . because , as mentioned above , the milder palladium - catalyzed stille 
 cross - coupling reaction gave the highest yields 
 of functionalized bodipys , in this study 
 we investigated stille couplings , using four different stannane reagents , 
 in increasing order of reactivity : tributylphenyltin , trimethyl[(tributylstannyl)ethynyl]silane , 
 tributyl(1-ethoxyvinyl)tin , and 2-(tributylstannyl)thiophene , to produce 
 8-mono- , 3,8-di- , and 3,5,8-trisubstituted bodipys , as shown in schemes 25 . anticipating 
 regioselectivity in the reactions of the 3,5,8-trichloro - bodipy 5 , we first addressed the global stille coupling to demonstrate 
 that functionalization at the 3,5,8-positions of bodipy 5 can be performed in one step . a typical procedure involved refluxing 
 a toluene mixture of 3,5,8-trichloro - bodipy 5 and excess 
 organotin reagent ( 4.5 equiv ) , in the presence of pd(pph3)4 , for 524 h. the global stille reactions proceeded 
 in moderate to good yields , producing the corresponding 3,5,8-trisubstituted 
 bodipys 810 in 4283% yields 
 ( scheme 2 ) . the least reactive tin reagent 
 used , the tributylphenyltin , required the longest time refluxing in 
 toluene for 24 h , and gave the lowest yield of product . products 810 showed red - shifted absorptions compared 
 with the starting material 3,5,8-trichloro - bodipy 5 , 
 which absorbs at max 538 nm ; bodipy 10 showed the most red - shifted absorption ( max 648 
 nm ) , followed by bodipy 8 ( max 594 
 nm ) and 9 ( max 546 nm ) ( see table 1 ) . this is a result of a nearly perpendicular orientation 
 of the phenyl groups on the trisubstituted bodipys 9 , 
 particularly the 8-phenyl , which prevents orbital interactions , whereas 
 the linear trimethylsilylethynyl group lies in the plane of the bodipy 
 core , efficiently extending its -conjugation ( see figure 2 ) . in addition , in the case of the electron - rich 
 thienyl group , the thiophene tends to decrease the homo lumo 
 gap , therefore increasing the absorbance wavelength relative to the 
 phenyl analogue ( vide infra ) . x - ray structures of bodipys 8 and 10 , 
 with 50% ellipsoids . unlike the structures of 5 and 7 ( figure 1 ) , both 8 and 10 have 
 their propanoate substituents extended , with torsion angles about 
 their ch2ch2 bonds 170.4 and 179.7 
 for 8 , 157.7 and 179.7 for 10 . all three of the thiophenes in 8 exhibit disorder 
 by 2-fold rotation about the c c bonds joining them to the 
 rest of the molecule , with only the major conformers shown in figure 2 . the central c3n2b ring in 
 both molecules has a slight boat distortion , with b and the c opposite 
 it lying , respectively , 0.18 and 0.04  on the same side of the 
 plane formed by the other four atoms for 8 , 0.19 and 
 0.04  for 10 . the n2b and bf2 planes form a dihedral angle of 89.8 in both 8 and 10 . the 12-atom bodipy core of 8 makes 
 a dihedral angle of 89.6 with the 8-thiophene plane and 68.1 
 and 39.9 with the other two . regioselective coupling reactions 
 were performed on the 3,5,8-trichloro - bodipy 5 using 
 the same organotin reagents as described above for 
 the synthesis of 810 , but in a 1:1 
 ratio to the bodipy rather than in excess . we anticipated monosubstitution 
 at the most electrophilic 8-position of the bodipy . the coupling reaction with 2-(tributylstannyl)thiophene 
 in refluxing toluene for 5 h gave the monothienyl - bodipy 11 as the sole product , in 72% yield ( scheme 3 ) . under similar conditions , bodipy 13 was also obtained in a reasonable yield ( 65% ) along with trace amount 
 of the corresponding 3,8-disubstituted product . using the least reactive 
 tin reagent , bodipy 12 was obtained in only 21% yield ; 
 however , the yield of 12 was increased to 57% when 2 
 equiv ( rather than 1 ) of organotin were used , and no disubstitution 
 product was detected . the 1,7-propanoate groups likely lead to an 
 increased dihedral angle between the bodipy core and the phenyl group , 
 resulting in blue - shifted absorption and emission bands . the x - ray 
 structures of bodipys 1113 are shown 
 in figure 3 . both 11 and 12 have two independent 
 molecules 
 in the crystal ( only one shown in figure 3 ) , 
 and the thiophene in both molecules of 11 is disordered . the propanoate substituents of all three molecules are extended , with 
 torsion angle magnitudes in the range 175.9179.8 for 11 , 170.0176.6 for 12 , and 178.5 
 and 179.8 for 13 . in the central c3n2b ring of all three molecules , only the b atom is distinctly 
 out of plane , by a mean distance of 0.10  for 11 , 0.14  for 12 , and 0.12  for 13 . in all three molecules , the bn2 and bf2 planes 
 form dihedral angles of 89.7 to 89.8. the 12-atom bodipy 
 core of 11 forms dihedral angles of 89.3 and 90.0 
 with the thiophene planes in the two independent molecules . the bodipy 
 core of 12 forms dihedral angles with the phenyl rings 
 of 86.5 and 87.8 for the two independent molecules . for the three new 8-substituted bodipys 1113 , different functional groups were introduced at the 3,5-positions 
 by stille coupling reactions using 2.4 equiv of selected organotin 
 reagents , as shown in scheme 4 . specifically , the 8-thienyl - bodipy 11 was functionalized 
 at the 3,5-positions with phenyl and trimethylsilylethynyl groups 
 to provide bodipys 14 and 15 , the 8-phenyl - bodipy 12 was functionalized with thienyl and trimethylsilylethynyl 
 groups to give bodipys 16 and 17 , and bodipy 13 was functionalized with phenyl and thienyl groups to produce 
 bodipys 18 and 19 . these double stille reactions 
 proceeded in good yields ( 5178% ) , the highest obtained using 
 the most reactive 2-(tributylstannyl)thiophene reagent and the lowest 
 using the least nucleophilic tributylphenyltin . five of these differentially 
 substituted bodipy compounds ( specifically 1519 ) were also characterized by single crystal x - ray crystallography , 
 shown in figure 4 . x - ray structures of bodipys 1519 , with 50% ellipsoids . of the thiophene - containing molecules , 15 has its 
 thiophene ordered , 18 has one ordered and the other disordered , 
 and 16 has both disordered . all five 
 molecules have their methyl propanoate substituents extended , with 
 torsion angle magnitudes about the ch2ch2 bonds in the range 168.9179.3. there is some variation 
 in the conformations of the central c3n2b rings . bodipy 16 has the b atom 0.19  out of the best 
 plane of the other five atoms , while in the two independent molecules 
 of 19 , the deviations are 0.19 and 0.35  . bodipys 15 and 17 have the slight boat distortion , with 
 deviations 0.12 ( for b ) and 0.05  ( for c ) in 15 , and 0.22 and 0.04  , respectively , for 17 . the 
 central c3n2b ring of 18 differs 
 from the others , having a twist conformation with the b atom 0.07 
  and a n atom 0.13  on opposite sides of the plane of 
 the other four atoms . the bn2/bf2 dihedral angles 
 in 15 , 16 , 17 , and 19 are all 89.690.0 , while that of 18 is 
 slightly smaller , 88.9. in 15 , the bodipy core 
 forms a dihedral angle of 77.0 with the thiophene plane . in 16 and 17 , respectively , the bodipy core forms 
 a dihedral angle of 87.6 and 80.0 with the phenyl plane . 
 in 18 , the bodipy core forms dihedral angles of 58.1 
 and 44.9 with the two thiophene planes . in 19 , 
 the bodipy core forms dihedral angles in the range 60.574.9 
 ( mean value 70.5 ) with the phenyl planes in the two independent 
 molecules . the synthesis of asymmetric bodipys was also accomplished 
 using 
 first 2 equiv of organotin reagent , followed by a second organotin ; 
 this strategy produces asymmetrical bodipys on account of the higher 
 reactivity at the 8-position and the molecular symmetry about the 
 3,5-positions . the reaction of bodipy 5 with 2 equiv 
 of trimethyl[(tributylstannyl)ethynyl]silane produced the 3,8-disubstituted 
 bodipy 20 as the major product in 53% yield , along with 
 a trace amount of the trisubstituted - bodipy 10 ( scheme 5 ) . bodipy 20 was 
 then treated with 2-(tributylstannyl)thiophene to yield bodipy 21 in 63% yield . the structure of bodipys 20 and 21 were confirmed by their x - ray crystallography , shown in 
 figure 5 . as with all previous structures , except for 5 and 7 , the methyl propanoate substituents of 20 and 21 are extended , with torsion angle magnitudes 
 about the ch2ch2 bonds in the range 
 175.0 to 179.0. 
 the conformation of the central rings are fairly planar , similar to 
 those of 1113 , with the b atom 0.11 
  out of the c3n2 plane for 20 and 0.15  for 21 . the bn2/bf2 dihedral angle is typical of these compounds , 89.6 for 20 and 89.5 for 21 . in 21 , 
 the bodipy core forms a dihedral angle of 43.1 with the thiophene 
 plane . attempts to introduce three different groups at the 3- , 5- , and 8-positions of the bodipy core were also investigated 
 by 
 consecutive stille reactions using different organotin reagents , to 
 produce a completely asymmetric bodipy . the phenyl group was first 
 regioselectively introduced at the most reactive 8-position to give 
 the 8-phenyl bodipy 12 . next , thiophene was introduced 
 at the 3-position of bodipy 12 using 1 equiv of 2-(tributylstannyl)thiophene , 
 resulting in the isolation of asymmetric bodipy 22 in 
 43% yield along with a trace amount of bodipy 16 ( scheme 6 ) . finally , an ethoxyvinyl group was introduced 
 into the 5-position of bodipy 22 by reaction with tributyl(1-ethoxyvinyl)tin 
 to provide the fully asymmetric bodipy 23 in 51% yield . the spectroscopic properties 
 of all bodipys synthesized , including uv / visible absorption and steady - state 
 fluorescence emission , were studied in dichloromethane solution , and 
 the results are summarized in table 1 . furthermore , 
 as an example , figure 6 shows the normalized 
 absorption and fluorescence spectra for bodipys 5 , 9 , 13 , and 15 ( others are presented 
 in supporting information ) . all bodipys 
 show typical absorption and emission spectra for this type of compound , 
 with strong absorption bands corresponding to the s0s1 transition ( log  = 4.15.1 ) , a shoulder at 
 shorter wavelength due to the 01 vibrational band of the same 
 transition , and stokes - shifted emission bands . the stokes shifts vary 
 considerably for this group of bodipys , from 186 to 1524 cm ; bodipys 8 , 16 , and 18 , bearing 
 3,5-thienyl groups , have the largest stokes shifts ( 14271524 
 cm ) followed by bodipys 2123 , bearing only one thienyl group at the 5-position . in agreement 
 with these values , 1500 cm have been reported for 3,5-thienyl - substituted bodipys , and larger 
 values were achieved upon boron substitution with alkynylaryl groups 
 via intramolecular energy transfer . it has also 
 been shown that 8-thienyl - substituted bodipys normally show small 
 stokes shifts ( ca . 350 cm ) typical of bodipy derivatives , and that 2,6-dithienyl - bodipys can show even 
 larger stokes shifts , presumably due to increased geometry relaxation , 
 i.e. , the geometry difference between the s0 and the s1 states , upon photoexcitation . the 
 introduction of chlorines at the 3,5-positions slightly red - shifts 
 the absorption and emission bands and increases the molar extinction 
 coefficients and fluorescence quantum yields , as previously observed , 
 due to the decrease in nonradiative deactivation processes . as expected , the global stille 
 coupling on bodipy 5 caused pronounced red - shifts in 
 the absorption and emission bands , particularly for the 3,5,8-trimethylsilylethynyl - bodipy 10 which showed a 110 nm bathochromic shift compared with 5 due to larger electronic coupling with the bodipy chromophore , 
 therefore extending the -conjugation system and decreasing 
 the homo the aromatic substituents on 8 and 9 , particularly the 8-aryl groups , orient themselves nearly perpendicular 
 to the bodipy core to minimize steric interactions , inducing smaller 
 red - shifts . in addition , the electron - releasing effect of the thiophene 
 group tends to decrease the homo lumo gap , inducing larger red - shifts compared with the phenyl - substituted 
 analogues ( see below ) . similarly , the 3,5,8-trisubstituted bodipys 1419 , 21 , and 23 obtained by mixed stille coupling reactions all show bathochromic 
 shifts ( 21107 nm ) compared with bodipy 5 ; the 
 greatest red - shifts were observed for the trimethylsilylethynyl - containing 
 bodipys 15 , 1719 , and 21 , and the smallest for the phenyl - containing bodipys 14 and 16 . regioselective coupling at only 
 the 8-position caused a slight 
 blue - shift in the case of 8-phenyl - bodipy 12 , and a slight 
 red - shift in the case of 8-thienyl - bodipy 11 , as previously 
 observed , indicating that the most pronounced 
 effect on the absorption and emission wavelengths of the bodipys arise 
 from 3,5-aryl ( rather than 8-) substitution . the large dihedral angle 
 ( ca . 87 from crystal structure ) between the 8-phenyl group and 
 the bodipy core in 12 as a result of 1,7-disubstitution 
 induces blue - shifted absorption and emission spectra . on the other 
 hand , an 8-trimethylsilylethynyl group , as found in bodipy 10 , effectively extends the -conjugation , inducing a 46 nm bathochromic 
 shift . in agreement with these results , although the 8-thienyl group 
 forms an even larger dihedral angle with the bodipy core in 11 ( ca . 89 from crystal structure ) , the electron - releasing 
 effect of the thienyl group decreases the homo  lumo gap , therefore 
 increasing the absorbance and emission wavelengths relative to bodipy 12 . the fluorescence quantum 
 yields determined in dichloromethane were 
 significantly higher for the phenyl - substituted bodipys compared with 
 the thienyl- and trimethylsilylethynyl - substituted bodipy analogues . for example , the 8-phenyl - bodipy 12 showed the highest 
 quantum yield ( f = 0.86 ) of all bodipys in this 
 series , whereas the 3,5,8-trimethylsilylethynyl - bodipys 10 showed the lowest ( f = 0.01 ) . these results are 
 in agreement with our previous studies and reflect 
 the greater freedom of rotation of the smaller thienyl group in comparison 
 with phenyl , even in the presence of the 1,7-propanoate substituents , 
 increasing the amount of energy lost to nonradiative decay to the 
 ground state . the aryl - ring rotation has been demonstrated to be critical 
 in determining the excited - state dynamics of bodipys , and in particular 
 their fluorescence quantum yields . on the other 
 hand , the trimethylsilylethynyl groups increase the nonradiative molecular 
 relaxation which decreases the fluorescence quantum yields . we have 
 previously shown that upon deprotection of the trimethylsilyl group , 
 the resulting 8-ethynyl - bodipy shows increased fluorescence quantum 
 yield . normalized uv / visible absorption ( solid 
 line ) and fluorescence 
 emission ( dashed line ) spectra of selected bodipys 5 , 9 , 13 , and 15 ( left to right ) in 
 dichloromethane solution . fluorescence quantum yields ( f ) were calculated 
 as follows : rhodamine 6 g was used as the 
 standard for compounds 59 and for 
 compounds 11 and 12 ; rhodamine b was used 
 as the standard for compounds 13 , 14 , 16 , 17 , 22 , and 23 ; 
 methylene blue was used as the standard for compounds 10 , 15 , 1821 . a 
 very useful method for transformation of dipyrroketones into 
 5-chlorodipyrromethene hydrochlorides by using phosgene is inhibited 
 by the presence of conjugated 2,9-ester substituents . however , catalytic 
 debenzylation followed by decarboxylative iodination affords a 2,9-diiodopyrroketone 
 which does undergo the phosgene reaction to provide 2,5,9-trichlordipyrromethene 
 hydrochlorides after nucleophilic addition / elimination with chloride 
 to replace the two iodo groups . treatment of these 3,5,8-trichlorodipyrromethene 
 salts with bf3et2o gives a 3,5,8-trichlorobodipy 
 that readily undergoes regioselective stille coupling at the 8-position , 
 or a combination of differential 3,8-disubstitution or 3,5- and 8-trisubstitution . x - ray structures of 14 new bodipys are reported and analyzed . global 
 stille coupling at the 3,5,8-positions of bodipy 5 caused 
 up to 110 nm bathochromic shifts ( in the case of the 3,5,8-trimethylsilylethynyl - bodipy 10 ) in the absorption and emission bands of the bodipys . regioselective 
 and consecutive stille coupling reactions produced a variety of asymmetric 
 bodipys ; the 3,5-aryl and 3(5)- and/or 8-ethynyl substitution induced 
 the largest bathochromic shifts whereas the presence of a 3(5)-thienyl 
 substituent caused the largest stokes shifts ( up to 1524 cm ) . the 8-phenyl - bodipys showed the highest fluorescence quantum yields 
 ( f = 0.340.86 ) , followed by the 8-thienyl - bodipys 
 ( f = 0.100.27 ) , whereas the 8-ethynyl - bodipys 
 showed the lowest quantum yields ( f = 0.010.21 ) . h and c nmr spectra 
 were measured on a 400 mhz nmr spectrometer at room temperature . visible 
 absorption spectra and fluorescence emission spectra were recorded 
 on a commercial spectrophotometer ( 190900 nm scan range ) . relative fluorescence quantum yields 
 ( f ) were calculated as follows : rhodamine 6 g was 
 used as the standard for compounds 59 and for compounds 11 and 12 ; rhodamine 
 b was used as the standard for compounds 13 , 14 , 16 , 17 , 22 , and 23 ; methylene blue was used as the standard for compounds 10 , 15 , 1821 . water- and air - sensitive 
 reactions were performed under argon protection and in dry solvents . benzyl 4-(2-methoxycarbonylethyl)-3,5-dimethylpyrrole-2-carboxylate 
 ( 15.7 g , 0.05 mol ) was dissolved in anhydrous diethyl ether ( 500 ml ) , 
 and bromine ( 2.56 ml , 0.05 mol ) was added dropwise . the solution turned 
 brown during addition , and the mixture was further stirred at room 
 temperature overnight , whereupon a thick precipitate was apparent . then the diethyl ether was removed under vacuum to give a pink solid 
 that was dissolved in methanol ( 100 ml ) and refluxed overnight . when 
 the solution was cooled to room temperature , a precipitate appeared , 
 which was filtered and washed with cold methanol to give a white solid 
 ( 10.70 g , 70% ) of dipyrromethane 1 . h nmr ( 400 mhz ; cdcl3 ) :  9.00 ( s , 2h ) , 7.387.31 
 ( m , 10h ) , 5.25 ( s , 4h ) , 3.97 ( s , 2h ) , 3,56 ( s , 6h ) , 2.75 ( t , 4h ) , 
 2.51 ( t , 4h ) , 2.28 ( s , 6h ) ; c nmr ( 100 mhz ; cdcl3 ) : 173.9 , 161.4 , 136.5 , 130.9 , 128.5 , 128.0 , 127.9 , 127.2 , 
 120.2 , 118.0 , 65.5 , 51.8 , 34.5 , 22.4 , 19.2 , 10.4 ; hrms ( esi - tof ) calcd 
 for c35h39n2o8 [ m + h ] 615.6928 , found 615.6908 . a solution of dipyrromethane 1 ( 2.0 
 g , 3.25 mmol ) in acetic acid ( 80 ml ) was treated with pb(oac)4 ( 3.12 g , 7.0 mmol ) and stirred at room temperature for 4 
 d under argon . then pbo2 ( 2.4 g , 9.3 mmol ) was added , and 
 the solution was stirred for another 2 d. the solution was centrifuged , 
 and the supernatant was poured into ice  water . the precipitate 
 was collected and dissolved in diethyl ether before being washed with 
 water , 5% aqueous nahco3 , and brine and then dried over 
 anhydrous na2so4 . then the solution was concentrated 
 to a minimum volume and crystallized in a refrigerator to give product 
 as a yellowish white solid ( 1.2 g , 60% ) , mp 170171 c 
 ( lit . h nmr ( 400 mhz ; cdcl3 )  7.387.31 
 ( m , 10h ) , 5.00 ( s , 4h ) , 3,67 ( s , 6h ) , 3.01 ( broad , 4h ) , 2.71 ( broad , 
 4h ) , 2.27 ( s , 6h ) ; c nmr ( 100 mhz ; cdcl3 ) 
  176.7 , 173.6 , 161.7 , 135.0 , 132.2 , 130.2 , 128.7 , 128.4 , 127.7 , 
 127.0 , 121.7 , 66.8 , 51.6 , 35.2 , 20.3 , 10.4 ; hrms ( esi - tof ) calcd for 
 c35h36n2o9 [ m + h ] : 629.2499 , found 629.2497 . dipyrroketone 2 ( 6.14 g , 0.01 mol ) 
 was dissolved in 300 ml of thf , and then 5% pd / c ( 350 mg ) catalyst 
 was added . after tlc showed that reaction was complete , it was stopped 
 and the reaction solution was passed through a celite cake to remove 
 the catalyst . the sticky solid on the top of the celite cake was redissolved 
 and neutralized in water with aqueous ammonia , and the solution was 
 passed through the celite cake once again . the filtrate was acidified 
 with acetic acid which caused a precipitate to appear from the aqueous 
 solution . the thf filtrate 
 was evaporated and combined with the solid to give a total of 4.0 
 g ( 92% ) of the 1,9-dicarboxylic acid product . this dicarboxylic acid 
 was suspended in a solution of h2o ( 250 ml)/meoh ( 100 ml ) , 
 and nahco3 ( 4.48 g , 51.2 mmol ) was added to the solution , 
 which was sonicated to form a slurry and then a clear solution . then 
 a solution of i2 ( 3.84 g , 14.72 mmol ) in methanol ( 60 ml ) 
 was added to the mixture dropwise at room temperature with vigorous 
 stirring , and some brown solid was formed during the addition . when 
 the addition of iodine was complete , the stirring was continued for 
 another 2 h and the precipitate was filtered and washed with water , 
 saturated aqueous nahco3 , and water again , followed by 
 hexane to remove any excess i2 , to yield a yellowish solid . the product was left to air - dry or dissolved in ch2cl2 and dried over anhydrous na2so4 before 
 removal of the solvent to give diiodopyrroketone 3 ( 4.2 
 g , 75% ) , mp 162 c . nmr ( 400 mhz ; cdcl3 )  9.47 ( s , 2h ) , 3.65 ( s , 6h ) , 2.70 ( t , j = 7.6 hz , 4h ) , 2.61 ( t , j = 7.6 hz , 4h ) , 2.04 ( s , 
 6h ) ; c nmr ( 100 mhz ; cdcl3 )  173.8 , 
 173.5 , 132.7 , 128.5 , 126.4 , 51.8 , 33.9 , 20.9 , 12.2 ; hrms ( esi - tof ) 
 calcd for c19h23i2n2o5 [ m + h ] : 612.9691 , found : 612.9697 . diiodopyrroketone 3 ( 1.0 g , 1.63 mmol ) was dissolved in chcl3 ( 150 
 ml ) , and excess phosgene in toluene solution was added to the solution , 
 which turned deep red with time ; the reaction was monitored by uv / vis 
 spectrophotometry , and the reaction was stopped when a sharp absorption 
 peak appeared at about 480 nm . then n2 gas was passed through 
 the solution to purge it of excess phosgene into an aqueous nahco3 solution trap . solvent was removed in vacuo to give a reddish 
 solid , which was dissolved in 150 ml of chcl3 , followed 
 by addition of diea ( 2 ml , 7.0 equiv ) . the solution was stirred for 
 30 min , bf3oet2 ( 2.1 ml , 10 equiv ) was 
 added , and the solution turned bright red with a yellow fluorescence 
 under long wavelength uv light . the reaction was monitored by uv / vis 
 spectroscopy , which showed a sharp peak at 538 nm . the mixture was 
 stirred for 24 h before being washed with water , saturated aqueous 
 nahco3 , and brine and then dried over anhydrous na2so4 to give a red solid . the product was purified 
 by silica gel column chromatography , eluting with ethyl acetate / hexane 
 ( 1:4 ) to give the product 5 ( 430 mg , 55% ) as the major 
 fraction and 6 ( 88.5 mg , 11% ) and 7 ( 40.2 
 mg , 5% ) as minor products . bodipy 5 : mp 156157 
 c ; h nmr ( 400 mhz ; cdcl3 )  3.72 
 ( s , 6h ) , 3.20 ( t , j = 8.0 hz , 4h ) , 2.57 ( t , j = 8.0 hz , 4h ) , 2.05 ( s , 6h ) ; c nmr ( 100 mhz ; 
 cdcl3 )  172.5 , 144.0 , 142.3 , 134.9 , 128.5 , 127.3 
 52.0 , 33.8 , 22.8 , 8.9 ; hrms ( esi - tof ) calcd for c19h20 bcl3fn2o4 [ m  f ] : 475.0566 , found : 475.0562 ; uv / vis ( ch2cl2 ) : max (  ) = 538 nm ( 112  200 ) . bodipy 6 : mp 116118 c ; h nmr 
 ( 400 mhz ; cdcl3 )  7.57 ( s , 1h ) , 3.71 ( s , 3h ) , 3.71 
 ( s , 3h ) , 3.20 ( m , 4h ) , 2.58 ( m , 4h ) , 2.07 ( s , 3h ) , 2.04 ( s , 3h ) ; c nmr ( 100 mhz ; cdcl3 )  172.5 , 172.5 , 143.5 , 
 142.6 , 142.4 , 136.8 , 130.1 , 129.1 , 128.7 , 127.3 , 126.8 , 52.0 , 51.9 , 
 33.9 , 33.9 , 22.8 , 22.2 , 9.9 , 8.9 ; hrms ( esi - tof ) calcd for c19h21bcl2fn2o4 [ m  
 f ] 441.0955 , found 441.0935 , uv / vis ( ch2cl2 ) : max (  ) = 534 nm ( 60  300 ) . bodipy 7 : mp 148149 c ; h nmr 
 ( 400 mhz ; cdcl3 )  7.58 ( s , 2h ) , 3.73 ( s , 3h ) , 3.21 
 ( t , j = 8.1 hz , 4h ) , 2.59 ( t , j = 
 8.1 hz , 4h ) , 2.08 ( s , 3h ) ; c nmr ( 100 mhz ; cdcl3 )  172.8 , 143.1 , 142.5 , 138.7 , 130.4 , 128.8 , 51.9 , 34.0 , 22.2 , 
 9.8 ; hrms ( esi - tof ) calcd for c19h22bclfn2o4 [ m  f ] 407.1345 , found 407.1342 . uv / vis ( ch2cl2 ) : max (  ) 
 = 528 nm ( 38  000 ) . bodipy 5 ( 15 
 mg , 0.03 mmol ) and pd(pph3)4 ( 2.0 mg , 5% ) were 
 added to a round - bottomed flask . the flask was flushed with argon , 
 and then anhydrous toluene ( 15 ml ) was injected , followed by injection 
 of the organotin reagent ( 0.14 mmol , 4.5 equiv ) . the solution was 
 refluxed for 12 h until the starting material disappeared from tlc 
 and the uv / vis spectrum showed a sharp peak around 600 nm . then the 
 toluene was removed , and the residue was taken up in ch2cl2 , washed with water and brine , and then dried over 
 anhydrous na2so4 . the crude product was purified 
 by chromatography to give the fully ( tri- ) substituted products . ( 16.0 mg , 83% ) , mp 198 c ; h nmr ( 400 mhz ; cdcl3 )  7.567.49 
 ( m , 5h ) , 7.207.09 ( m , 4h ) , 3.63 ( s , 6h ) , 2.332.22 
 ( m , 6h ) , 2.00 ( s , 6h ) , 1.941.86 ( m , 2h ) ; c nmr 
 ( 100 mhz ; cdcl3 )  172.5 , 149.7 , 142.4 , 134.4 , 133.2 , 
 133.0 , 131.7 , 129.7 , 128.8 , 128.0 , 127.4 , 127.2 , 51.6 , 35.1 , 21.4 , 
 10.6 ; hrms ( esi - tof ) calcd for c31h30bf2n2o4s3 [ m + h ] 639.1429 , found 639.1429 . uv / vis ( ch2cl2 ) : 
 max (  ) = 594 nm ( 43  700 ) . ( 8.2 mg , 42% ) , mp 165166 
 c ; h nmr ( 400 mhz ; cdcl3 )  7.537.38 
 ( m , 15h ) , 3.60 ( s , 6h ) , 2.12 ( m , 4h ) , 2.00 ( m , 4h ) , 1.80 ( s , 6h ) ; c nmr ( 100 mhz ; cdcl3 )  172.4 , 156.6 , 142.23 , 
 134.6 , 132.0 , 131.3 , 129.7 , 129.4 , 128.8 , 128.7 , 128.4 , 128.3 , 127.8 , 
 51.5 , 34.5 , 21.7 , 9.7 ; hrms ( esi - tof ) calcd for c37h35bfn2o4 [ mw  f ] 601.2674 , 
 found 601.2656 . uv / vis ( ch2cl2 ) : max (  ) = 546 nm ( 29  500 ) . ( 12.6 mg , 61% ) , mp 171 c ; h 
 nmr ( 400 mhz ; cdcl3 )  3.69 ( s , 6h ) , 3.25 
 ( t , j = 8.0 hz , 4h ) , 2.25 ( t , j = 
 8.0 hz , 4h ) , 2.08 ( s , 6h ) . 0.32 ( s , 9h ) , 0.28 ( s , 9h ) ; c nmr ( 100 mhz ; cdcl3 )  172.8 , 140.5 , 136.0 , 134.7 , 
 132.8 , 118.3 , 114.0 , 113.3 , 99.2 , 96.4 , 51.7 , 34.2 , 21.4 , 14.1 , 9.5 ; 
 hrms ( esi - tof ) calcd for c34h48bf2n2o4si3 [ m + h ] 680.3014 , 
 found 680.3001 . uv / vis ( ch2cl2 ) : max (  ) = 648 nm ( 88  000 ) . the selective 
 coupling reactions followed the procedure used for the global coupling 
 reactions . the only difference was that 1 equiv of organotin reagent 
 was used instead of excess organotin reagents . starting with bodipy 5 ( 29.2 mg , 
 0.059 mmol ) , 23.07 mg ( 72% ) of the monosubstituted bodipy 
 was obtained , mp 212 c ; h nmr ( 400 mhz ; cdcl3 )  7.56 ( dd , j = 5.0 , 1.3 hz , 1h ) , 
 7.15 ( d , j = 1.8 hz , 1h ) , 7.09 ( d , j = 1.6 , 1h ) , 3.62 ( s , 6h ) , 2.282.02 ( m , 6h ) , 1.96 ( s , 6h ) , 
 1.891.83 ( m , 2h ) ; c nmr ( 100 mhz ; cdcl3 )  172.1 , 145.0 , 143.3 , 133.5 , 132.8 , 131.0 , 129.1 , 128.5 , 
 127.4 , 126.9 , 51.7 , 34.8 , 21.5 , 8.8 ; hrms ( esi - tof ) calcd for c23h23bcl2fn2o4s 
 [ mw  f ] 523.0833 , found 523.0836 . uv / vis ( ch2cl2 ) : max (  ) = 548 nm 
 ( 77  600 ) . a 1:1 ratio 
 of bodipy 5 ( 30.4 mg , 0.061 mmol ) and tributylphenyltin 
 ( 20.0 l , 
 0.061 mmol ) was used to give the product 12 ( 7.0 mg , 
 21% ) ; a 1:2 ratio of bodipy 5 ( 32.6 mg , 0.066 mmol ) and 
 tributylphenyltin ( 40.0 l , 0.122 mmol ) was used to give the 
 product 12 ( 19.45 mg , 57% ) , mp 172 c ; h nmr ( 400 mhz ; cdcl3 )  7.567.38 ( m , 5h ) , 
 3.58 ( s , 6h ) , 2.04 ( m , 4h ) , 1.95 ( m , 10h ) ; c nmr ( 100 
 mhz ; cdcl3 )  171.9 , 144.4 , 143.2 , 141.1 , 133.3 , 
 130.1 , 129.9 , 129.0 , 128.1 , 126.5 , 51.6 , 34.3 , 21.4 , 8.7 ; hrms ( esi - tof ) 
 calcd for c25h25bcl2fn2o4 [ m  f ] : 517.1268 , found : 517.1278 . uv / vis ( ch2cl2 ) : max (  ) 
 = 534 nm ( 69  200 ) . starting 
 with bodipy 5 ( 20.0 mg , 0.04 mmol ) , 15.2 mg ( 65% ) of 13 was isolated , 
 mp 121 c ; h nmr ( 400 mhz ; cdcl3 )  
 3.71 ( s , 6h ) , 3.30 ( t , j = 8.8 hz , 4h ) , 2.59 ( t , j = 8.8 hz , 4h ) , 2.04 ( s , 6h ) , 0.30 ( s , 9h ) ; c nmr ( 100 mhz ; cdcl3 )  172.6 , 143.0 , 142.1 , 131.7 , 
 126.4 , 119.3 , 114.8 , 98.4 , 51.8 , 34.2 , 21.7 , 8.8 ; hrms ( esi - tof ) calcd 
 for c24h29bcl2fn2o4si [ m  f ] 537.1321 , found 537.1340 . uv / vis 
 ( ch2cl2 ) : max (  ) = 
 584 nm ( 67  600 ) . bodipy 11 ( 16.5 mg , 0.030 mmol ) and pd(pph3)4 ( 3.4 mg , 5% ) were added to a round - bottomed flask and 
 flushed with 
 argon several times . anhydrous toluene ( 10 ml ) was added , followed 
 by injection of tributylphenyltin ( 28.0 l , 3.0 equiv ) ; the 
 solution was refluxed for 12 h until a sharp peak appeared in the 
 uv / vis spectrum at 562 nm in ch2cl2 . the reaction 
 was stopped , and the toluene was removed ; the residue was taken up 
 in ch2cl2 , which was washed with water and brine 
 and then dried over anhydrous na2so4 . the crude 
 product was purified by silica gel column chromatography , eluting 
 with ethyl acetate / hexane ( 1:4 ) to give the product as a purple - red 
 solid . h nmr ( 400 mhz ; cdcl3 )  7.597.14 
 ( m , 13h ) , 3.65 ( s , 6h ) , 2.292.27 ( m , 6h ) , 2.071.96 
 ( m , 2h ) , 1.86 ( s , 6h ) ; c nmr ( 100 mhz ; cdcl3 )  172.6 , 157.2 , 142.5 , 134.5 , 132.3 , 131.9 , 129.6 , 128.9 , 
 128.7 , 128.3 , 127.9 , 127.8 , 127.2 , 51.6 , 35.1 , 21.5 , 9.8 ; hrms ( esi - tof ) 
 calcd for c35h33bfn2o4s [ m  f ] 607.2238 , found 607.2234 . uv / vis ( ch2cl2 ) : max (  ) = 560 nm 
 ( 17  800 ) . starting 
 with bodipy 11 ( 14.3 mg , 0.026 mmol ) afforded the product 15 ( 11.1 
 mg , 64% ) , mp 187 c . h nmr ( 400 mhz ; cdcl3 )  7.54 ( m , 1h ) , 7.14 ( m , 1h ) , 7.08 ( m , 1h ) , 3.63 ( s , 6h ) , 
 2.19 ( m , 6h ) , 2.02 ( s , 6h ) , 1.90 ( m , 2h ) , 0.33 ( s , 18h ) ; c nmr ( 100 mhz ; cdcl3 )  172.4 , 141.7 , 137.8 , 134.0 , 
 133.6 , 133.2 , 129.0 , 128.1 , 127.2 , 113.7 , 96.2 , 51.6 , 34.9 , 21.2 , 
 9.5 , 0.3 ; hrms ( esi - tof ) calcd for c33h42bf2n2o4ssi2 667.2465 , found 
 667.2473 . uv / vis ( ch2cl2 ) : max (  ) = 609 nm ( 89  100 ) . starting with bodipy 12 ( 15.1 mg , 0.029 mmol ) afforded 
 the product 16 ( 14.4 
 mg , 78% ) , mp 166 c . h nmr ( 400 mhz ; cdcl3 )  7.597.47 ( m , 9h ) , 7.14 ( dd , j = 5.1 , 3.6 hz , 2h ) , 
 3.60 ( s , 6h ) , 2.142.09 ( m , 4h ) , 1.991.96 ( m , 10h ) ; c nmr ( 100 mhz ; cdcl3 )  172.3 , 149.3 , 142.2 , 
 141.2 , 134.5 , 132.0 , 131.8 , 131.5 , 129.5 , 129.3 , 128.9 , 128.5 , 128.4 , 
 127.3 , 51.5 , 34.5 , 21.3 , 10.5 ; hrms ( esi - tof ) calcd for c33h31bfn2o4s2 [ m  
 f ] 613.1802 , found 613.1803 . uv / vis ( ch2cl2 ) : max (  ) = 574 nm ( 38  900 ) . starting with bodipy 12 ( 17.3 mg , 0.033 mmol ) gave 17 ( 15.7 mg , 71% ) , mp 182 
 c . h nmr ( 400 mhz ; cdcl3 )  7.527.45 
 ( m , 3h ) , 7.377.28 ( m , 2h ) , 3,57 ( s , 6h ) , 2.062.00 
 ( m , 10h ) , 1.941.89 ( m , 4h ) , 0.33 ( s , 18h ) ; c 
 nmr ( 100 mhz ; cdcl3 )  172.2 , 149.3 , 141.5 , 140.5 , 
 137.3 , 133.8 , 132.9 , 129.6 , 128.8 , 128.3 , 112.8 , 96.2 , 51.5 , 34.3 , 
 21.1 , 9.5 , 1.0 ; hrms ( esi - tof ) calcd for c35h43bf2n2nao4si2 [ m + na ] 683.2720 , found 683.2723 . uv / vis ( ch2cl2 ) : max (  ) = 594 nm ( 47  900 ) . starting with bodipy 13 ( 12.6 mg , 
 0.023 mmol ) gave 18 ( 11.3 mg , 76% ) , mp 179 
 c . h nmr ( 400 mhz ; cdcl3 )  7.547.49 
 ( m , 4h ) , 7.11 ( ddd , j = 5.2 , 3.8 , 1.6 hz , 2h ) , 3.72 
 ( s , 6h ) , 3.39 ( t , j = 8.2 hz , 4h ) , 2.64 ( t , j = 8.2 hz , 4h ) , 2.09 ( s , 6h ) , 0.32 ( s , 18h ) ; c nmr ( 100 mhz ; cdcl3 )  173.0 , 147.9 , 141.2 , 133.8 , 
 131.9 , 131.7 , 129.1 , 128.7 , 127.3 , 119.2 , 113.6 , 99.4 , 51.7 , 34.4 , 
 31.6 , 21.6 , 10.6 , 1.1 ; hrms ( esi - tof ) calcd for c32h35bfn2o4s2si [ mw  
 f ] 633.1885 , found 633.1883 . uv / vis ( ch2cl2 ) : max (  ) = 636 nm ( 29  500 ) . starting with bodipy 13 ( 11.0 mg , 0.02 mmol ) gave product 19 ( 6.5 mg , 51% ) , 
 mp 195 c . h nmr ( 400 mhz ; cdcl3 )  
 7.457.36 ( m , 10h ) , 3.72 ( s , 6h ) , 3.39 ( t , j = 7.8 hz , 4h ) , 2.67 ( t , j = 7.8 hz , 4h ) , 1.89 ( s , 
 6h ) , 0.33 ( s , 9h ) ; c nmr ( 100 mhz ; cdcl3 ) 
  173.0 , 155.5 , 141.3 , 133.1 , 131.9 , 129.7 , 128.8 , 128.1 , 127.7 , 
 113.3 , 99.3 , 51.6 , 34.4 , 21.0 , 9.7 , 1.1 ; hrms ( esi - tof ) calcd for 
 c36h39bfn2o4si [ m  
 f ] 621.2756 , found 621.2757 . uv / vis ( ch2cl2 ) : max (  ) = 601 nm ( 38  900 ) . bodipy 5 ( 15.0 
 mg , 0.03 mmol ) and pd(pph3)4 ( 3.4 mg , 5% ) were 
 added to a round - bottomed flask . the flask was flushed with argon 
 and then anhydrous toluene ( 15 ml ) was injected , followed by injection 
 of the organotin reagent trimethyl[(tributylstannyl)ethynyl]silane 
 ( 22.3 l , 0.06 mmol ) . the mixture was refluxed until the starting 
 material disappeared as observed by tlc and the uv / vis spectrum showed 
 a sharp peak around 615 nm . then the toluene was removed and the residue 
 was taken up in ch2cl2 and washed with water , 
 brine and then dried over anhydrous na2so4 . the crude product was purified by silica gel column chromatography 
 to give the disubstituted product 20 ( 10.0 mg , 53% ) , 
 mp 122 c . h nmr ( 400 mhz ; cdcl3 )  
 3.68 ( s , 3h ) , 3.68 ( s , 3h ) , 3.25 ( m , 4h ) , 2.56 ( m , 4h ) , 2.07 ( s , 3h ) , 
 2.02 ( s , 3h ) , 0.30 ( s , 9h ) , 0.27 ( s , 9h ) ; c nmr ( 100 
 mhz ; cdcl3 )  172.8 , 172.7 , 144.0 , 142.1 , 140.5 , 
 135.2 , 133.3 , 132.9 , 126.6 , 118.9 , 114.4 , 113.1 , 98.7 , 96.0 , 51.8 , 
 51.7 , 34.2 , 34.1 , 21.7 , 21.4 , 9.5 , 8.2 , 0.3 , 1.2 ; hrms ( esi - tof ) calcd 
 for c29h39bclf2n2o4si2 [ m + h ] 619.2198 , found 619.2185 . uv / vis ( ch2cl2 ) : max (  ) 
 = 616 nm ( 46,800 ) . bodipy 20 ( 10 mg , 
 0.016 mmol ) and pd(pph3)4 ( 2.0 mg , 5% ) were 
 added to a round - bottomed flask . the flask was flushed with argon , 
 and then anhydrous toluene ( 15 ml ) was injected , followed by injection 
 of the organotin reagent 2-(tributylstannyl)thiophene ( 8.0 l , 
 1.5 equiv ) ; the mixture was then refluxed for 5 h. the toluene was 
 removed , and the residue was taken up in ch2cl2 , washed with water and brine , and then dried over anhydrous na2so4 . the crude product was purified by silica gel 
 column chromatography to give the fully substituted product 21 ( 6.8 mg , 63% ) , mp 151 c . h nmr ( 400 mhz ; 
 cdcl3 )  7.75 ( d , j = 3.44 hz , 1h ) , 
 7.58 ( d , j = 4.92 hz , 1h ) , 7.20 ( t , j = 4.24 hz , 1h ) , 3.71 ( s , 3h ) , 3.70 ( s , 3h ) , 3.37 ( t , j = 7.88 hz , 2h ) , 3.28 ( t , j = 7.36 hz , 3h ) , 2.64 
 ( t , j = 7.88 hz , 3h ) , 2.57 ( t , j = 7.36 hz , 3h ) , 
 2.15 ( s , 3h ) , 2.09 ( s , 3h ) . 0.30 ( s , 9h ) , 0.28 ( s , 9h ) ; c nmr ( 100 mhz ; cdcl3 )  172.9 , 151.9 , 150.2 , 142.5 , 
 139.2 , 133.6 , 132.9 , 132.6 , 131.7 , 129.7 , 129.5 , 127.5 , 118.5 , 113.6 , 
 112.0 , 99.3 , 96.6 , 51.7 , 51.6 , 34.4 , 34.2 , 21.6 , 21.4 , 10.9 , 9.6 . 
 1.0 ; hrms ( esi - tof ) calcd for c33h42bf2n2o4ssi2 [ m + h ] 667.2465 , 
 found 667.2478 . uv / vis ( ch2cl2 ) : max (  ) = 645 nm ( 29  500 ) . bodipy 12 ( 21.6 
 mg , 0.042 mmol ) and pd(pph3)4 ( 5.3 mg , 5% ) were 
 added to a round - bottomed flask . the flask was flushed with argon , 
 and then anhydrous toluene ( 15 ml ) was injected , followed by injection 
 of the organotin reagent 2-(tributylstannyl)thiophene ( 14.0 l , 
 1.0 equiv ) ; the mixture was then refluxed for 5 h. the toluene was 
 removed , and the residue was taken up in ch2cl2 , washed with water and brine , and then dried over anhydrous na2so4 . the crude product was purified by silica gel 
 column chromatography hexane / ethyl acetate ( 4:1 ) to give product 22 ( 10.5 mg , 43% ) , mp 164 c . h nmr ( 400 
 mhz ; cdcl3 )  7.587.18 ( m , 8h ) , 3.58 ( s , 
 6h ) , 2.111.91 ( m , 14h ) ; c nmr ( 100 mhz ; cdcl3 )  172.2 , 172.1 , 150.4 , 143.2 , 143.1 , 142.2 , 141.1 , 
 133.9 , 132.0 , 131.6 , 130.4 , 130.1 , 129.7 , 129.0 , 129.0 , 128.9 , 128.2 , 
 127.4 , 126.1 , 51.6 , 34.4 , 26.9 , 21.9 , 10.5 , 7.5 ; hrms ( esi - tof ) calcd 
 for c29h28bclf2n2nao4s [ m + na ] 607.1417 , found 607.1391 . uv / vis ( ch2cl2 ) : max (  ) = 555 nm 
 ( 33  300 ) . bodipy 22 ( 9.4 
 mg , 0.016 mmol ) and pd(pph3)4 ( 2.1 mg , 5% ) were 
 added to a round - bottomed flask . the flask was flushed with argon , 
 and then anhydrous toluene ( 15 ml ) was injected , followed by injection 
 of the organotin reagent tributyl(1-ethoxyvinyl ) ( 11.0 l , 1.5 
 equiv ) ; the mixture was refluxed for 5 h. the toluene was removed , 
 and the residue was taken up in ch2cl2 , washed 
 with water and brine , and then dried over anhydrous na2so4 . the crude product was purified by silica gel column 
 chromatography hexane / ethyl acetate ( 4:1 ) to give the fully substituted 
 bodipy 23 ( 5.6 mg , 51% ) , mp , > 260 c . h nmr ( 400 mhz ; cdcl3 )  7.597.15 ( m , 8h ) , 
 4.62 ( s , 2h ) , 3.90 ( q , j = 7.1 , 2h ) , 3.57 ( s , 6h ) , 
 2.111.91(m , 14h ) , 1.35(t , j = 7.1 , 3h ) ; c nmr ( 100 mhz ; cdcl3 )  172.4 , 172.3 , 152.3 , 
 151.5 , 142.6 , 142.30 142.0 , 141.9 , 135.4 , 134.4 , 133.4 , 131.5 , 129.5 , 
 129.3 , 129.3 , 128.8 , 128.6 , 128.4 , 128.4 , 128.2 , 127.2,91.1 , 63.7 , 
 53.4 , 51.5 , 34.5 , 21.4 , 21.1 , 14.3 , 10.5 , 9.3 ; hrms ( esi - tof ) calcd 
 for c33h36bf2n2o5s [ m + h ] 621.2406 , found 621.2406 . uv / vis ( ch2cl2 ) : max (  ) = 559 nm ( 13  000 ) .
catalytic hydrogenation 
 of dibenzyl 5-dipyrroketone-2,9-dicarboxylates 
 followed by decarboxylative iodination affords a 2,9-diiododipyrroketone 
 which gives a 2,5,9-trichlorodipyrromethene hydrochloride after nucleophilic 
 addition / elimination , with adventitious chloride to replace the two 
 iodide groups . 
 treatment with bf3et2o 
 gives a 3,5,8-trichloro - bodipy that readily undergoes regioselective 
 stille coupling at the 8-position , or homo / mixed couplings at the 
 3,8- or 3,5- and 8-positions . 
 stepwise and controlled replacement 
 of the 3,5- and 8-chlorine atoms using stille reagents results in 
 formation of a completely unsymmetrical trisubstituted bodipy . 
 several 
 examples of unsymmetrical bodipys were synthesized and characterized 
 using this methodology . 
 structure features of new bodipys are discussed 
 within the context of 14 new x - ray structures , and photophysical parameters 
 of all new bodipy compounds are reported and discussed .