Domino Cross-Scholl Reaction of Tetracene with Molecular Benzene: Synthesis, Structure, and Mechanism

Post-Formation of Fused Pentagonal Structure on Fjord Region of Polyaromatic Hydrocarbons under Hydrothermal Conditions

This study explores the synthesis of cyclopenta-fused polyaromatic hydrocarbons (CP-PAHs) via Pt-catalyzed cyclization in water, focusing on the formation of fused pentagonal rings within heavily fused PAH frameworks. Utilizing platinum catalysts at lower temperatures (200-260 °C) in water, led to the successful synthesis of singly cyclized CP-PAHs. The reaction conditions facilitated the mono-cyclization of substrates such as dibenzo[g,p]chrysene and its isomers, yielding the desired products while suppressing the formation of bis-cyclized compounds. The use of Fe2O3 as an additive in conjunction with PtO2 was effective to suppress hydrogenation of the substrates and products. The products exhibited a redshift in UV-visible absorption and photoluminescence bands due to a decrease in the HOMO-LUMO energy gap. These findings highlight the potential of Pt-catalyzed cyclization for the controlled synthesis of CP-PAHs, with implications for various applications in materials science.

π-Extended Rubrenes via Dearomative Annulative π-Extension Reaction

Among a large variety of organic semiconducting materials, rubrene (5,6,11,12-tetraphenyltetracene) represents one of the most prominent molecular entities mainly because of its unusually high carrier mobility. Toward finding superior rubrene-based organic semiconductors, several synthetic strategies for related molecules have been established. However, despite its outstanding properties and significant attention in the field of materials science, late-stage functionalizations of rubrene remains undeveloped, thereby limiting the accessible chemical space of rubrene-based materials. Herein, we report on a late-stage π-extension of rubrene by dearomative annulative π-extension (DAPEX), leading to the generation of rubrene derivatives having an extended acene core. The Diels-Alder reaction of rubrene with 4-methyl-1,2,4-triazoline-3,5-dione occurred to give 1:1 and 1:2 cycloadducts which further underwent iron-catalyzed annulative diarylation. The thus-formed 1:1 and 1:2 adducts were subjected to radical-mediated oxidation and thermal cycloreversion to furnish one-side and two-side π-extended rubrenes, respectively. These π-extended rubrenes displayed a marked red shift in absorption and emission spectra, clearly showing that the acene π-system of rubrene was extended not only structurally but also electronically. The X-ray crystallographic analysis uncovered interesting packing modes of these π-extended rubrenes. Particularly, two-side π-extended rubrene adopts a brick-wall packing structure with largely overlapping two-dimensional face-to-face π-π interactions. Finally, organic field-effect transistor devices using two-side π-extended rubrene were fabricated, and their carrier mobilities were measured. The observed maximum hole mobility of 1.49 × 10-3 cm2V-1 s-1, which is a comparable value to that of the thin-film transistor using rubrene, clearly shows the potential utility of two-side π-extended rubrene in organic electronics.

Computational study of electron transport in halogen incorporated diindenotetracene compounds: crystal structure, charge transport and optoelectronic properties

The crystal structure, charge transport and optoelectronic properties of newly designed air-stable halogenated diindenotetracene (DIT) based OSCs are reported in this article. The structural, electronic and charge transport properties of the compounds are investigated using density functional theory (DFT) formalism. The air-stability and n-type characteristics are validated from their low lying LUMO energies (<-3.9 eV) and large electron affinity (EA) values (>3.0 eV). Compared with the parent DIT, the designed DIT-X compounds (except for DIT-I) exhibit larger electronic coupling (V^e is found to be ∼1.5 times larger than that of the bare DIT) and higher electron mobilities because of the effect of electron-withdrawing groups substituted at the peripheral positions of the DIT derivatives. The designed DIT-X compounds (except DIT-I) show high electron mobilities (∼2.4-5.4 cm² V^-1 s^-1), implying that the compounds can serve as promising electron transport materials. In addition, the UV-visible optical spectra of DIT derivatives (except DIT-F) display bathochromic shifts as compared to the bare DIT compound.