1,3,5,7,9-Pentakis(4-methoxyphenylthio)corannulene (3), 1,3,5,7,9-pentakis(2-naphthylthio)corannulene (4), and 1,3,6,8-tetrakis(4-methoxyphenylthio)corannulene (5b) have been synthesized by chlorination of corannulene with ICl in CH(2)Cl(2) at 25 degrees C and subsequent nucleophilic aromatic substitution with the appropriate sodium thiophenolate in DMEU at 25 degrees C. (1)H NMR titration studies demonstrate that these novel bowl-shaped hosts form 1:1 complexes with C(60) in toluene-d(8) solution with association constants of 454, 368, and 280 M(-1), respectively.

Nucleophilic aromatic substitution of all the chlorine atoms in 1,3,5,7,9-pentachlorocorannulene and in decachlorocorannulene by sodium alkanethiolates gives 1,3,5,7,9-pentakis(1-alkylthio)corannulenes, C 20 H 5 (SR) 5 , and decakis(1-alkylthio)corannulenes, C 20 (SR) 10 , respectively, with arms of varying lengths attached around the perimeter (R = n-propyl, n-hexyl, and ndodecyl). The corresponding reaction of decachlorocorannulene with ortho-C 6 H 4 (SNa) 2 gives pentakis(1,4-benzodithiino)corannulene, a molecular bowl with 6 Å flaps on all five sides. Such compounds represent attractive candidates for the formation of discotic liquid crystals and/or supramolecular complexes with fullerenes and other convex guests.Our discovery that the chlorination of corannulene (1) with I-Cl at room temperature gives pentachlorocorannulene with surprisingly high selectivity for the 1,3,5,7,9-isomer 2 1 opened the door to a new family of molecular bowls that bear substituents around the entire perimeter ( Figure 1). 1-3 Figure 1Corannulene (C 20 H 10 ) and several 1,3,5,7,9-pentakis-X derivatives Within this new family of compounds, the pentakis(SAr) derivatives 3 and 4 were found to be well-suited as hosts for the complexation of C 60 (K assoc = 10 2 -10 3 M -1 ). 3 The choice of aryl groups in these fullerene hosts was strongly influenced by the fact that C 60 exhibits good solubility in both anisole and methylnaphthalene, 4 and it is tempting to envision the arms of 3 and 4 embracing the C 60 in these complexes (Figure 2). This view is reinforced by the failure of unsubstituted corannulene (1) to show any evidence for binding to C 60 . 5Notwithstanding this appealing picture, the question remains whether or not 'intramolecular solvation' by the five tethered arenes represents the primary factor responsible for the superior binding ability of the pentakis(SAr) derivatives 3 and 4. The five sulfur atoms attached around the perimeter of the geodesic polyarene core in 3 and 4 must certainly render their concave surfaces more electron rich and more polarizable than the interior surface of the parent corannulene, and that could be the dominant factor. Figure 2 Hypothetical structure for the 1:1 complex C 60 ·3, with the five arms of 3 embracing the C 60To probe this issue, we have synthesized the 1,3,5,7,9-pentakis(S-CH 2 CH 2 CH 3 ) derivative 5, which lacks electron-rich p-systems on the arms but retains the geodesic polyarene core and the five attached sulfur atoms. As in our syntheses of 3 and 4, 3 the conversion of 2 to 5 could be effected under quite mild conditions. Thus, stirring 1,3,5,7,9-pentachlorocorannulene (2) with sodium 1-propanethiolate in 1,3-dimethylimidazolidin-2-one (dimethylethanourea = DMEU) at room temperature for 3 days gave 1,3,5,7,9-pentakis(1-propylthio)corannulene (5) in 38% yield, after purification. In the same manner, a 1,3,5,7,9-pentakis(1-alkylthio)corannulene with much longer arms 6 was also prepared from 2. 6 Starting from decachlorocorannulene (7), 7 the same reaction was used to make a fami...