truxene ( 10,15dihydro5hdiindeno[1,2a:1,2c]fluorene ) ( 1 ) is a useful platform for the threefold synthesis of crushed fullerene c60h30 ( 2 ) and other c 
 3vsymmetric molecules ( scheme 1),1 , 2 , 3 as well as being an attractive building block for the preparation of new materials to be used in molecular electronics.4 the laserinduced cyclodehydrogenation in the gas phase to form closedshell c60 fullerene has been previously demonstrated for 2 (  crushed fullerene)5 and other related functionalized compounds,6 whereas flashvacuum pyrolysis was used in the synthesis of fullerene c60 from c60h27cl3 as the precursor.7 
  synthesis of crushed fullerene c60h30 ( 2 ) . fullerene c60 and triazafullererene c57n3 were also formed from 2 and c57h33n3 
 8 precursors , respectively , by cyclodehydrogenation on a platinum surface.9 stm images were obtained for deposited triangular fullerene precursors that , after annealing at 750 k , formed roundshaped c60 , indistinguishable from those images of authentic c60 fullerene , and ballshaped heterofullerene c57n3 , which was previously unknown . we now report our efforts towards the synthesis of new crushed fullerenes already containing 78 of the 90 c we envisioned two possible truxenebased c60h24 isomers 3 and 5 , which are more advanced crushed fullerenes than 2 and could be respectively accessed from the suitably functionalized trialkylated truxene precursors 4 and 6 by means of multiple pdcatalyzed direct arylations ( scheme 2).10 these expanded truxenes could also give rise to c60 by laserpromoted cyclodehydrogenation ( scheme 3 ) . interestingly , 5 was proposed to be a plausible intermediate in the formation of c60 fullerene,11 although its synthesis and characterization have never been reported . although remarkable multiple intermolecular palladiumcatalyzed arylations have been reported,12 for the intramolecular palladiumcatalyzed arylation reaction of bromoarenes , the formation of 5 from 6 would involve the highest order ( sixfold ) arylation of this type to date.[12a ] 4,9,14trisubstituted truxenes 7 were prepared by acidcatalyzed trimerization of the corresponding 7substituted 1indanones.[1b ] triple alkylation of their lithium or sodium trianions afforded the expected products 4 as crude mixtures of syn and anti isomers , as determined from h nmr spectra of the crude materials , which surprisingly could not be isomerized in the presence of base to form exclusively the syn isomer , as we had previously observed in the vast majority of cases.[1a ] thus , 4a was obtained as a 1.3:1 mixture of syn and anti isomers after chromatographic purification , whereas in the case of 4b , pure anti isomer was isolated after column chromatography and precipitation from mixtures of ch2cl2 and pentane ( scheme 4 ) . the structure of anti4b was confirmed by xray diffraction analysis.13 
  synthesis of trialkylated precursors 4 and xray crystal structure of anti4b . given that all attempts to convert 4a directly into crushed fullerene 3 by pdcatalyzed intramolecular direct arylation afforded complex mixtures from which 3 could not be identified , we turned our attention to the cyclization of 4b . it seemed clear to us that this cyclization could be sequentially carried out by initial triple pdcatalyzed cyclization of 4b to form 8 after dehydrogenation , followed by triple demethylation , formation of the corresponding tristriflate , and subsequent triple pdcatalyzed intramolecular arylation ( scheme 5 ) . after screening a range of reaction conditions , we found that the triple pdcatalyzed cyclization of anti4b proceeded in moderate yield in the presence of pd(oac)2 and phdavephos . treatment of the resulting mixture with 2,3dichloro5,6dicyano1,4benzoquinone ( ddq ) forced the triple dehydrogenation to afford 8 in 31  % yield over the two steps , the structure of which was confirmed by xray diffraction.13 demethylation of 8 was carried out with bbr3 to form 9 as a poorly soluble solid in excellent yield . however , conversion of 9 into tristriflate 10 could only be achieved at low temperatures and in low yield . furthermore , 10 turned out to be unstable under ambient conditions , and attempts to cyclize this tristriflate to form 3 in the presence of different pd catalysts failed , providing complex mixtures , presumably due to its low stability . not discouraged by these results , we decided to focus our efforts on the synthesis of crushed fullerene 5 . thus , tribromotruxene 11 was prepared by direct bromination of truxene,[1b ] which can be readily obtained in a multigram scale from 1indanone.14 triple alkylation of the corresponding sodium trianion with 1bromo2(bromomethyl)naphthalene furnished the desired hexabrominated precursor 6 . the triple alkylation of 11 afforded mixtures of anti and syn isomers that , as happened in the case of 4 , could not be isomerized in the presence of base to form exclusively the syn isomer.[1a ] nevertheless , pure syn isomer could be obtained upon precipitation from mixtures of ch2cl2 and pentane ( scheme 6 ) . a conceivable alternative synthesis of 5 by the direct acidcatalyzed triannulation strategy15 would require the development of a synthesis of unknown ketone indeno[4,3,2,1lmno]acephenanthrylen1(2h)one or its regioisomer.16 
  synthesis of crushed fullerene c60h24 ( 5 ) . hexabromotruxene syn6 was next subjected to different palladiumcatalyzed direct arylation reaction conditions . due to the high insolubility of both syn6 and the product of this transformation , ldims experiments were used as a tool to find the optimal conditions for the intramolecular arylation . when pd(oac)2 , bnme3nbr , and k2co3[1 g ] were used under different reaction conditions , only complex mixtures were detected , and no clear formation of 5 was observed . the use of phosphine ligands such as xantphos , 1,3bis(diphenylphosphanyl)propane ( dppp ) or phdavephos did not result in any improvement . fortunately , when ethylenebis(diphenylphosphine ) ( dppe ) was used as the ligand , we were able to observe clear evidence for the formation of 5 . after extensive optimization of the reaction conditions , ldi experiments of the isolated solid in positive and negative modes showed a single peak at m / z 744 with an experimental isotopic pattern that was consistent with the theoretical distribution calculated for 5 ( figure 1 ) . this peak corresponds to the target crushed fullerene , which could be isolated in 44  % yield as a highly insoluble orange solid . formation of 5 from syn6 involves a remarkable sequence of nine reactions catalyzed by palladium : sixfold intramolecular arylation and a triple dehydrogenation process . ( right ) theoretical and experimental isotopic pattern for c60h24 ( 5 ) . to verify that 5 is a direct precursor of c60 fullerene , a sample of pure c60h24 was analyzed by maldi and ldims in positive and negative modes by using increasing laser powers , and the results in positive mode were compared to those arising from the analogous experiments on a sample of pure c60 . maldims analysis at the threshold of ion formation in negative mode using 2,5dihydroxybenzoic acid ( dhb ) as the matrix showed exclusively the molecular ion of 3 , whereas at a higher laser power in the range of 129 j , this precursor ion underwent threefold h2 loss giving [ c60h22 ] , [ c60h20 ] , and [ c60h18 ] ( m / z 742 , 740 , and 738 , respectively , figure 2 , a ) . on the other hand , when the sample was analyzed in positive mode by ldims to avoid interferences derived from the matrix at a laser power in the range of 126 j , a peak at m / z 721 corresponding to the formation of [ c60 + h ] could be identified , which underwent further c2 fragmentations to give a series similar to that resulting from pure c60 fullerene ( figure 2 , b).[5b ] ( a ) ( top ) maldi mass spectrum of 5 at the threshold of ion formation using dhb as the matrix . ( bottom ) maldi mass spectrum of 5 at 129 j using dhb as the matrix . ( b ) ( top ) ldi mass spectrum of c60 fullerene at a laser power of 106 j . ( center ) ldi mass spectrum of c60 fullerene at a laser power of 115 j . ( bottom ) ldi mass spectrum of 5 at a laser power of 126 j . a new , advanced crushed fullerene c60h24 has been synthesized by a sixfold palladiumcatalyzed intramolecular arylation , which takes place in a remarkable 44  % yield , equivalent to an average 87  % yield per c  c bond formation , and subsequent in situ dehydrogenation . openshell c60 derivative 5 gives rise to c60 fullerene by applying highpower laser irradiation in ldims experiments . general procedures : reactions were performed under argon atmosphere in solvents dried by passing through an activated alumina column on a puresolvtm solvent purification system ( innovative technologies , inc . thinlayer chromatography was carried out using tlc aluminum sheets coated with 0.2 mm of silica gel ( merck gf234 ) . chromatographic purifications were carried out using flash grade silica gel ( sds chromatogel 60 acc , 4060 m ) . nmr spectra were recorded at 25 c with a bruker avance 300 , 400 ultrashield and bruker avance 500 ultrashield apparatus , or at 120 c with a bruker avance 500 ultrashield apparatus . mass spectra were recorded with a microtof focus bruker daltonics mass spectrometer ( esi ) or with an autoflex bruker daltonics ( maldi and ldi ) equipped with a nitrogen laser ( 337 nm ) with a mean energy of 165.6 j per pulse and a beam dimension of 4    2.5 mm . samples were measured at least four times under the same conditions and a minimum of 200 shots were accumulated per full spectrum . crystal structure determinations were carried out with a brukernonius diffractometer equipped with an appex 2 4k ccd area detector , a fr591 rotating anode with mok radiation , montel mirrors as monochromator and a kryoflex lowtemperature device ( t = 173 c ) . programs used : data collection apex2 , data reduction bruker saint v/.60a and absorption correction sadabs . structure solution and refinement : crystal structure solution was achieved by using direct methods as implement in shelxtl and visualized by using the program xp . missing atoms were subsequently located from difference fourier synthesis and added to the atom list . leastsquares refinement on f 
  using all measured intensities was carried out using the program shelxtl . 5,10,15tris[(1bromonaphthalen2yl)methyl]4,9,14tribromo10,15dihydro5hdiindeno[1,2a:1,2c]fluorine ( 4a ) : a suspension of 4,9,14tribromo10,15dihydro5hdiindeno[1,2a:1,2c]fluorene ( 360 mg , 0.62 mmol ) in anhydrous dmf ( 5 ml ) was added over a suspension of nah ( 60  % in mineral oil , 82 mg , 2.04 mmol ) in anhydrous dmf ( 5 ml ) at 0 c under ar atmosphere . after ultrasonicating the resulting mixture for 50 min , a solution of 1bromo2(bromomethyl)naphthalene ( 577 mg , 1.92 mmol ) in anhydrous dmf ( 10 ml ) was added and the mixture was stirred at room temperature for 16 h. h2o ( 20 ml ) was added and the precipitate formed was filtered off and dissolved in ch2cl2 ( 50 ml ) . the resulting green solution was dried with mgso4 , filtered and concentrated under reduced pressure . purification by silica gel column chromatography ( cyclohexane / ch2cl2 8:2 ) gave a major fraction containing 4a as a mixture of syn and anti isomers together with unidentified impurities . this fraction was partially dissolved in ch2cl2 ( 10 ml ) and precipitated with pentane ( 30 ml ) . the supernatant was removed and the solid was washed again with pentane ( 3   20 ml ) and dried under reduced pressure giving the title compound , yield 331 mg ( 0.268 mmol , 41  % ) ; paleyellow solid ; syn / anti = 1.3:1 ; m.p . h nmr ( 500 mhz , cdcl3 ) :  = 8.228.16 ( m , 4.9 h , syn , anti ) , 8.13 ( d , j = 8.5 hz , 2 h , anti ) , 7.80 ( d , j = 9.6 hz , 1 h , anti ) , 7.747.69 ( m , 5.9 h , syn , anti ) , 7.687.63 ( m , 5.9 h , syn , anti ) , 7.627.58 ( m , 4.9 h , syn , anti ) , 7.577.47 ( m , 10 h ) , 7.467.43 ( m , 3.9 h , syn ) , 7.437.39 ( m , 4.9 h , syn , anti ) , 7.367.33 ( m , 3 h , anti ) , 7.26 ( d , j = 8.4 hz , 3.9 h , syn ) , 7.09 ( t , j = 8.4 hz , 1 h , anti ) , 6.96 ( t , j = 7.6 hz , 3.9 h , syn ) , 6.89 ( dt , j = 7.4 , 0.9 hz , 3.9 h , syn ) , 6.876.84 ( m , 1 h , anti ) , 6.81 ( d , j = 7.6 hz , 1 h , anti ) , 6.796.76 ( m , 1 h , anti ) , 6.63 ( t , j = 7.6 hz , 1 h , anti ) , 6.44 ( t , j = 7.5 hz , 1 h , anti ) , 6.416.36 ( m , 2 h , anti ) , 6.12 ( dd , j = 8.5 , 6.1 hz , 3.9 h , syn ) , 5.99 ( dd , j = 9.7 , 5.9 hz , 1 h , anti ) , 3.773.71 ( m , 3.9 h , syn ) , 3.703.67 ( m , 1 h , anti ) , 3.59 ( dd , j = 13.8 , 7.0 hz , 1 h , anti ) , 3.49 ( dd , j = 13.8 , 6.6 hz , 1 h , anti ) , 3.22 ( dd , j = 13.8 , 8.0 hz , 1 h , anti ) , 3.16 ( dd , j = 14.1 , 8.6 hz , 3.9 h , syn ) , 2.76 ( dd , j = 13.9 , 9.8 hz , 1 h , anti ) ppm . c nmr ( 126 mhz , cdcl3 ) :  = 150.66 , 150.31 , 149.54 , 149.16 , 144.95 , 144.43 , 142.51 , 142.41 , 141.14 , 140.64 , 139.30 , 138.95 , 137.65 , 137.26 , 137.23 , 137.01 , 136.87 , 136.68 , 136.30 , 135.92 , 133.31 , 133.28 , 133.24 , 133.20 , 133.15 , 132.91 , 132.85 , 132.37 , 132.24 , 132.21 , 132.20 , 128.27 , 128.18 , 128.08 , 128.02 , 127.97 , 127.94 , 127.88 , 127.86 , 127.84 , 127.79 , 127.74 , 127.68 , 127.60 , 127.40 , 127.37 , 127.24 , 127.17 , 127.14 , 126.99 , 126.87 , 126.84 , 126.25 , 126.02 , 125.99 , 125.85 , 125.80 , 125.64 , 125.52 , 123.88 , 123.79 , 123.32 , 123.30 , 116.11 , 115.99 , 115.19 , 52.49 ( anti ) , 52.14 ( syn ) , 50.45 ( anti ) , 49.98 ( anti ) , 42.12 ( anti ) , 41.53 ( anti ) , 39.95 ( anti ) , 39.31 ( syn ) ( aromatic peaks missing due to overlapping ) ppm . ( 5r*,10s*,15s*)5,10,15tris[(1bromonaphthalen2yl)methyl]4,9,14trimethoxy10,15dihydro5hdiindeno[1,2a:1,2c]fluorine ( anti4b ) : to a mixture of 4,9,14trimethoxy10,15dihydro5hdiindeno[1,2a:1,2c]fluorine ( 600 mg , 1.39 mmol ) in anhydrous thf ( 55 ml ) at 78 c was added nbuli ( 2.5 m in hexanes , 1.94 ml , 4.86 mmol ) and the mixture was slowly warmed to 10 c for 3 h. then , 1bromo2bromomethylnaphthalene ( 1.67 g , 5.56 mmol ) in anhydrous thf ( 20 ml ) was added and the mixture was warmed to room temperature . after 30 min at that temperature , the mixture was diluted with etoac and washed with saturated aqueous nacl , dried with mgso4 , and the volatiles evaporated . the residue was purified by chromatography ( cyclohexane / ch2cl2 , 8:2 to 1:1 ) to give 4b as a 3:1 mixture of anti / syn isomers together with unidentified impurities . after precipitation from ch2cl2/pentane mixtures , pure anti4b was obtained , yield 1.01 g ( 0.93 mmol , 67  % ) ; m.p . h nmr ( 400 mhz , cdcl3 ) :  = 8.25 ( dt , j = 8.6 , 1.0 hz , 1 h ) , 8.22 ( d , j = 8.6 hz , 1 h ) , 8.18 ( dd , j = 8.6 , 1.0 hz , 1 h ) , 7.78 ( d , j = 7.0 hz , 1 h ) , 7.73 ( d , j = 7.0 hz , 1 h ) , 7.65 ( d , j = 8.4 hz , 1 h ) , 7.61 ( d , j = 5.5 hz , 1 h ) , 7.59 ( d , j = 6.2 hz , 1 h ) , 7.55 ( dt , j = 8.7 , 1.6 hz , 1 h ) , 7.51 ( dd , j = 6.2 , 1.4 hz , 1 h ) , 7.497.41 ( m , 5 h ) , 7.38 ( d , j = 8.4 hz , 1 h ) , 7.32 ( ddd , j = 8.0 , 6.8 , 1.2 hz , 1 h ) , 7.147.09 ( m , 1 h ) , 7.06 ( d , j = 7.6 hz , 1 h ) , 7.02 ( d , j = 7.6 hz , 1 h ) , 6.94 ( dd , j = 8.1 , 7.4 hz , 1 h ) , 6.866.76 ( m , 4 h ) , 6.68 ( dt , j = 7.4 , 0.9 hz , 1 h ) , 6.40 ( dt , j = 7.4 , 0.9 hz , 1 h ) , 5.74 ( dd , j = 8.3 , 5.8 hz , 1 h ) , 5.64 ( t , j = 6.2 hz , 1 h ) , 5.47 ( dd , j = 9.5 , 5.3 hz , 1 h ) , 4.13 ( s , 3 h ) , 4.08 ( s , 3 h ) , 4.06 ( s , 3 h ) , 4.044.00 ( m , 1 h ) , 3.79 ( dd , j = 14.0 , 5.9 hz , 1 h ) , 3.64 ( dd , j = 13.8 , 6.3 hz , 1 h ) , 3.50 ( dd , j = 14.2 , 5.3 hz , 1 h ) , 3.21 ( dd , j = 14.0 , 8.3 hz , 1 h ) , 2.85 ( dd , j = 14.1 , 9.5 hz , 1 h ) ppm . c nmr ( 101 mhz , cdcl3 ) :  = 154.45 , 154.30 , 154.14 , 150.07 , 148.98 , 142.91 , 141.24 , 141.09 , 138.18 , 137.74 , 137.15 , 136.21 , 136.15 , 135.88 , 133.17 , 133.11 , 132.34 , 132.29 , 129.73 , 128.55 , 128.42 , 128.21 , 128.13 , 128.02 , 127.96 , 127.87 , 127.78 , 127.76 , 127.73 , 127.57 , 127.47 , 126.99 , 126.88 , 126.77 , 126.53 , 126.50 , 125.79 , 125.72 , 125.69 , 125.61 , 125.51 , 125.28 , 118.22 , 117.73 , 117.67 , 110.04 , 109.92 , 109.84 , 56.07 , 55.96 , 55.61 , 50.97 , 50.04 , 49.56 , 42.78 , 41.68 , 41.57 ( peaks missing due to overlapping ) ppm . hrms ( esi ) : m / z calcd . for c63h45br3nao3 [ m + na ] 1109.0811 ; found 1109.0779 . 3,13,23trimethoxybenzo[1,2e:3,4e:5,6e]tribenzo[l]acephenanthrylene ( 8) : compound anti4b ( 400 mg , 0.37 mmol ) , pd(oac)2 ( 82.4 mg , 0.37 mmol ) , phdavephos ( 70.6 mg , 0.19 mmol ) and k2co3 ( 102.3 mg , 0.74 mmol ) were suspended in anhydrous dma ( 1.9 ml , 0.2 m ) in a sealed tube under ar atmosphere , and the mixture was heated at 140 c for 16 h. after cooling to room temperature , chcl3 ( 20 ml ) was added and the mixture was washed with saturated aqueous nacl ( 3   15 ml ) , dried with mgso4 , and concentrated to dryness . the resulting crude material was dissolved in toluene ( 10 ml ) , then ddq ( 840 mg , 3.7 mmol ) was added and the reaction was stirred at 120 c for 6 h. after cooling to room temperature , the solution was washed with 2 m solution of koh ( 3   10 ml ) , dried with mgso4 , and concentrated to a volume of ca . 2 ml ( higher yields were obtained when the crude material was not taken to dryness ) . purification by flash chromatography ( cyclohexane / chcl3 , 7:3 to 0:1 ) afforded the product as a brownish solid that became insoluble after drying , yield 96.5 mg ( 0.11 mmol , 31  % over two steps ) ; m.p . h nmr ( 400 mhz , c2d2cl4 ) :  = 9.24 ( d , j = 8.4 hz , 3 h ) , 9.10 ( d , j = 9.1 hz , 3 h ) , 8.42 ( s , 3 h ) , 8.12 ( dd , j = 8.0 , 1.4 hz , 3 h ) , 8.06 ( d , j = 8.6 hz , 3 h ) , 7.94 ( d , j = 8.6 hz , 3 h ) , 7.85 ( ddd , j = 8.4 , 6.8 , 1.5 hz , 3 h ) , 7.74 ( ddd , j = 7.9 , 6.8 , 1.0 hz , 3 h ) , 7.61 ( d , j = 9.2 hz , 3 h ) , 4.12 ( s , 9 h ) ppm . c nmr ( 101 mhz , c2d2cl4 ) :  = 153.16 , 136.34 , 134.69 , 133.49 , 133.17 , 131.87 , 131.04 , 130.06 , 129.66 , 128.72 , 128.29 , 128.15 , 128.02 , 126.57 , 126.13 , 126.08 , 125.52 , 121.55 , 121.54 , 113.70 , 54.79 ppm . hrms ( maldi ) : m / z calcd . for c63h36o3 [ m ] 840.2664 ; found 840.2673 . 3,13,23trihydroxybenzo[1,2e:3,4e:5,6e]tribenzo[l]acephenanthrylene ( 9 ) : to a mixture of 8 ( 70 mg , 0.08 mmol ) in anhydrous ch2cl2 ( 10 ml ) was added bbr3 ( 1.0 m in ch2cl2 , 2.12 ml , 2.12 mmol ) and the mixture was stirred at room temperature for 5 d. after cooling to 0 c , h2o ( 10 ml ) was slowly added , the aqueous phase was extracted with ch2cl2 ( 10 ml ) , the combined organic layers were dried with mgso4 and the volatiles evaporated . the solid was triturated with hexanes and etoac to obtain 9 as a brown solid with low solubility in organic solvents , yield 57.4 mg ( 0.07 mmol , 91  % ) ; m.p . > 300 c . h nmr ( 400 mhz , [ d6]acetone ) :  = 10.00 ( s , 3 h ) , 9.32 ( d , j = 8.5 hz , 3 h ) , 9.15 ( d , j = 9.0 hz , 3 h ) , 9.01 ( s , 3 h ) , 8.24 ( d , j = 8.6 hz , 3 h ) , 8.16 ( d , j = 7.9 hz , 4 h ) , 8.02 ( d , j = 8.6 hz , 3 h ) , 7.887.83 ( m , 3 h ) , 7.757.71 ( m , 6 h ) ppm . full c nmr spectroscopic data could not be recorded due to the low solubility of the product . hrms ( fab ) : m / z calcd . for c60h30o3 [ m ] 798.2195 ; found 798.2194 . ( 5s*,10s*,15s*)2,7,12tribromo5,10,15tris[(1bromonaphthalen2yl)methyl]10,15dihydro5hdiindeno[1,2a:1,2c]fluorene ( syn6 ) : a suspension of 11 ( 360 mg , 0.62 mmol ) in anhydrous dmf ( 5 ml ) was added over a suspension of nah ( 60  % in mineral oil , 82 mg , 2.04 mmol ) in anhydrous dmf ( 5 ml ) at 0 c under ar atmosphere . after ultrasonicating the resulting mixture for 50 min , a solution of 1bromo2(bromomethyl)naphthalene ( 577 mg , 1.92 mmol ) in anhydrous dmf ( 10 ml ) was added and the mixture was stirred at room temperature for 16 h. h2o ( 20 ml ) was added and the precipitate formed was filtered off and redissolved in ch2cl2 ( 50 ml ) . the resulting green solution was dried with mgso4 , filtered , and concentrated under reduced pressure . purification by silica gel column chromatography ( cyclohexane / ch2cl2 , 8:2 ) gave a major fraction containing the desired syncompound together with variable amounts of the antiisomer and unidentified impurities . this fraction was partially dissolved in ch2cl2 ( 10 ml ) and precipitated with pentane ( 30 ml ) . the supernatant was removed and the solid was washed again with pentane ( 3   20 ml ) and dried under reduced pressure to give the title compound , yield 121 mg ( 0.098 mmol , 15  % ) ; paleyellow solid ; m.p . > h nmr ( 500 mhz , cdcl2cdcl2 , 120 c ) :  = 8.37 ( d , j = 9.3 hz , 3 h ) , 7.77 ( d , j = 2.9 hz , 3 h ) , 7.76 ( d , j = 3.0 hz , 3 h ) , 7.63 ( ddd , j = 8.5 , 6.9 , 1.4 hz , 3 h ) , 7.567.49 ( m , 6 h ) , 7.37 ( dd , j = 8.1 , 1.9 hz , 3 h ) , 7.05 ( d , j = 1.9 hz , 3 h ) , 6.86 ( d , j = 8.3 hz , 3 h ) , 4.72 ( dd , j = 7.1 , 7.1 hz , 3 h ) , 3.79 ( dd , j = 13.7 , 6.4 hz , 3 h ) , 3.34 ( dd , j = 13.9 , 8.2 hz , 3 h ) ppm . c nmr ( 126 mhz , cdcl2cdcl2 , 120 c ) :  = 148.2 , 140.1 , 138.2 , 135.6 , 133.1 , 132.1 , 129.6 , 128.1 , 128.1 , 127.4 , 126.9 , 126.9 , 126.4 , 125.7 , 124.6 , 122.8 , 119.8 , 46.1 , 40.6 ( one aromatic carbon missing due to overlapping ) ppm . hrms ( maldi ) : m / z calcd . for c60h35 triindeno[4,3,2,1lmno]acephenanthrylene ( 5 ) : a mixture of syn6 ( 62.8 mg , 0.051 mmol ) , pd(oac)2 ( 22.9 mg , 0.102 mmol ) , dppe ( 40.5 mg , 0.102 mmol ) , and k2co3 ( 105.7 mg , 0.765 mmol ) in anhydrous dma ( 0.5 ml ) under ar atmosphere was heated at 140 c in a sealed tube for 36 h. after cooling to room temperature , h2o ( 5 ml ) was added and the precipitated solid was filtered off and washed by centrifugation with h2o ( 6   15 ml ) , acetone ( 6   15 ml ) , satd . nacn ( 3   15 ml ) , acetone ( 6   15 ml ) and finally ch2cl2 ( 5   15 ml ) until the liquid phase remained colorless . after drying the remaining solid under reduced pressure , crushed fullerene c60h24 was obtained , yield 16.8 mg ( 0.023 mmol , 44  % ) ; darkorange highly insoluble solid ; m.p . > 300 c . nmr spectroscopic data could not be acquired due to the low solubility of the compound . hrms ( ldi ) : m / z calcd . for c60h24 [ m ] 744.1883 ; found 744.1848 .
the synthesis of a new c 
 3vsymmetric crushed fullerene c60h24 ( 5 ) has been accomplished in three steps from truxene through sixfold palladiumcatalyzed intramolecular arylation of a syntrialkylated truxene precursor . 
 laser irradiation of 5 induces cyclodehydrogenation processes that result in the formation of c60 , as detected by ldims .