A Series of Soluble Planar Oligorylenes up to Hexarylene

Preparation of large rylenes often needs the use of solubilizing groups along the rylene backbone,which results in the distortion of the skeleton and thus broadening of the absorption spectrum.In this work,we successfully synthesized 2,5,8,16,19,22-hexakis[2,6-bis(tri-fluoromethyl)phenyl]hexarylene(H)by using an oxidative fusion reaction of perylene trimer in 5%yield.The product is soluble in common organic solvents and could be purified with column chromatography.Single-crystal X-ray diffraction analysis revealed that the hexarylene core is not disturbed by the substituents very much and is almost planar.The longest absorption of H exhibits a sharp peak at 831 nm and an on-set at 875 nm in toluene with a small full-width-at-half-maximum(FWHM)of 660 cm^(-1).The molar extinction coefficient is as large as 131,000 M^(-1)cm^(-1).The substituents could not perturb the electronic properties of the hexarylene because aryl groups are perpendicular to the hexarylene core and the carbon atoms at 2,5,16,19-positions have negligible coeffi-cients on its HOMO and LUMO,estimated by theoretical calculations.As a result,the hexarylene having less absorption at the visible light region was stable enough in solution under the LED room light for more than 1 week.This strategy gives a useful guideline to establish the near-infrared materials that exhibit stability under ambient conditions.

Excellentπ-Bowl Semiconductors Based on C_(70)Subunit

As open substructures of fullerenes,aromaticπ-bowls are promising candidates as new organic semiconductors,as well as attractive hosts for fullerenes.We demonstrate herein the synthesis and characterization of a novel C_(2v)symmetricπ-bowl,pyracyleno[6,5,4,3,2,1-pqrstuv]pentaphene(3).Bowl 3 was equipped with two distinctive reactive sites,allowing for bromination and cross-coupling reactions to readily yield functionalized bowls with two 2,4,6-trimethylphenyl(5)and triethylsilyl(TES)-ethynyl(6)substituents,respectively.Variable-temperature 1H NMR analysis and density functional theory(DFT)calculations indicated bowl-to-bowl inversions of 3,5,and 6 at room temperature.By alternating the substituents,the crystal structures of the threeπ-bowls 3,5,and 6 could be controlled from 1D linear to 1D slipped to 2D herringbone packing motifs,providing insight into the packing behavior ofπ-bowls.1H NMR titration study indicated that the TES-ethynyl substituent enhanced the ability ofπ-bowl to bind C_(70)with an association constant of 2485 M−1.The C_(70)molecules withπ-bowls 3 and 6 formed 1:1 complexes,in which C_(70)molecules aggregated into zig-zag and 1D linear arrays,respectively.The hole mobility of 2.3 cm^(2)V^(−1)^s(−1)and electron mobility of 0.16 cm^(2)V^(−1)^s(−1)ofπ-bowl 3 and its complex with C_(70)were demonstrated,respectively,which proved a great value for the development of aromaticπ-bowl semiconductors with tunable properties for organic electronic devices.