Highly Luminescent and Semiconducting Supramolecular Organic Charge Transfer Complex Generated via H‐Bonding Interaction Pathway. Issue 4 (15th January 2023) - Ghosh, Sushobhan
Abstract: The construction of a charge transfer (CT) organic material with important electrical properties is demonstrated where the charge transfer state is generated via delocalization through H‐bonding interaction pathway. The reaction of simple organic molecule pyromellitic acid with orthophenylene diamine in 1:2 ratios gives a colorless cocrystal 1' . The rare transition phenomena of a colorless cocrystal 1' to an orange charge transfer state 1 take place in methanol water media over several days. The charge transfer state is isolated as orange single crystals of 1 which show semiconducting as well as fluorescent properties. The X‐ray diffraction analysis of 1 demonstrates the formation of charge separated extended H‐bonded network which is supposed to be solely responsible for the delocalization of charge in the system. This is the first example of formation of donor–acceptor‐based charge transfer material constructed by just tuning the H‐bond distance of a colorless cocrystalline state with non‐chalcogen and non‐halogenated molecules. Abstract : A colorless cocrystal 1' gets converted to orange charge transfer cocrystal 1 over 2–3 weeks in methanol. The structures of 1' and 1 are almost identical. The conversion of 1' to 1 takes place through H atom shift in the H‐bond. 1 is highly luminescent and semiconducting whereas 1' does not show any fluorescence and is an insulator.