Synthesis and Characterization of Cycloocta[1,2-a:6,5-a′]diindene as an Octagon-Containing Nonalternant Isomer of Pentacyclic Benzenoid Aromatic Hydrocarbons with Hidden Diradical Character That Induces Dimerization

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: May 12, 2025

Recently, the interest in nonbenzenoid hydrocarbons has resurged, focusing on replacement of two benzenoid hexagons with a pentagon/heptagon pair, which led to abundant azulenoid hydrocarbons. For ortho-fused three or more rings, replacing set pentagons and one octagon is also possible. Following this concept, we designed pentacyclic cyclooctadiindenes 4 5 5-8-5 tricyclic skeleton. Although pronounced open-shell nature hampered its synthesis, five examples were synthesized characterized as stable closed-shell molecules. A thin film 5a exhibited p-type transistor behavior hole mobility 0.63 × 10-2 cm2/(V·s). Optoelectronic measurements clearly showed nonalternant character 5. Heating photoirradiation solution afforded formal [6 + 4] cycloadduct. Theoretical calculations mechanistic investigations revealed occurrence stepwise formation C-C bonds, hidden emerges molecules close contact. Notably, dimeric π-complex 5·5, alleviated. The increased spatial overlap frontier orbitals reduction energy gap facilitate diradical-based bond formations. Our results demonstrate that electronic structures π-stacked compound can be tuned even for monomer compounds negligible character. This study will contribute establishing design strategies novel functional molecular materials based condensed state.

Language: Английский

The Surface Chemical Bond of a Nonbenzenoid Aromatic Hydrocarbon: Acepleiadylene versus Pyrene

Surface Science, Journal Year: 2024, Volume and Issue: 753, P. 122625 - 122625

Published: Oct. 11, 2024

Language: Английский