Polysubstituted Hexa-cata-hexabenzocoronenes: Syntheses, Characterization, and Their Potential as Semiconducting Materials in Transistor Applications

Abstract

A series of tetra- and octa-substituted hexa-cata-hexabenzocoronenes (cata-HBCs) were synthesized from tetraryl olefins via iodine- and iron chloride-catalyzed oxidative cyclodehydrogenation reactions. The substitutions on the periphery of the parent HBC serve to modify the photophysical properties, highest occupied molecular orbital–lowest unoccupied molecular orbital gaps, and thermal stabilities of the respective derivatives. The crystal structures were determined to display multiple twists in the framework, resulting in different packing motifs depending on the position, type, and number of functional groups on the hexabenzocoronene framework. Nearly perfect co-facial packing to marginally or extensively shifted co-facial stacks were obtained due to substitution. The single crystals of parent HBC were used to fabricate single-crystal field-effect transistors, from which the highest p-channel mobility of 0.51 cm2 V–1 s–1 was measured. Thin-film transistors of selected HBCs were also prepared, and 0.61 cm2 V–1 s–1 was obtained for MeHBC-2. These results attest the potential of these materials as semiconducting materials.

Coronenes, Benzocoronenes and Beyond: Modern Aspects of Their Syntheses, Properties, and Applications

“…For example, strong F…F intermolecular interactions were observed in the self‐assembly of fluorinated cata ‐HBCs [215] . Our group reported photophysical properties and HOMO/LUMO energies of tetrasubstituted and polysubstituted cata ‐HBCs [72] . In addition, crystal structures of tetrasubstituted derivatives revealed that HBCs packed in perfect or shifted co‐facial styles, depending on the substitutions.…”

“…In addition, the syntheses of fluorine‐substituted HBCs were also successful like the parent and alkoxy‐substituted HBCs, although their olefin precursors were slightly deactivated towards the oxidative cycylodehydrogenation reactions [71] . Our group reported [72] tetra‐substituted HBCs, whose production required consecutive usage of iodine‐mediated oxidative photocyclization and Scholl protocol. Using similar two‐step strategy, many others such as polysubstituted HBCs were also harnessed in good yields.…”

Accessing π‐expanded heterocyclics beyond dibenzothiophene: Syntheses and properties of phenanthrothiophenes

“…The introduction of heteroatom into the framework results in a molecular dipole (Table S1), which may also impact the packing motifs. In the case of DPT series, near cofacial packing and thus good π‐π overlap of the frameworks for nearest neighbors was obtained for DPT and Cl‐DPT, presumably due to geometric complementarity, and possibly the Cl…Cl interaction …”

New indolo[1,2‐c]quinazolines for single‐crystal field‐effect transistor: A united experimental and theoretical studies

“…The effect of a small substituent such as electron‐donating/withdrawing dipoles is accountable for the minor difference, which is noticed in LUMO values. [ 19 ]…”

“…[ 16 ] Recently, we reported high‐efficiency SCFETs using contorted pyreno[4,5 ‐a ]coronenes, tetrabenzo[ a,d,j,m ]coronenes, and dibenzo[ a,d ]coronenes as the channel materials. [ 17–19 ] These compounds display exactly co‐facial or shifted co‐facial packing. These molecules are nevertheless more symmetrical in shape, which allows more opportunity in ordered crystal packing.…”