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Ambient Stable Radical Cations, Diradicaloid π‐Dimeric Dications, Closed‐Shell Dications, and Diradical Dications of Methylthio‐Capped Rylenes
Author(s) -
Qi Qingbiao,
Burrezo Paula Mayorga,
Phan Hoa,
Herng Tun Seng,
Gopalakrishna Tullimilli Y.,
Zeng Wangdong,
Ding Jun,
Casado Juan,
Wu Jishan
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201701102
Subject(s) - dication , diradical , chemistry , delocalized electron , radical ion , intermolecular force , resonance raman spectroscopy , photochemistry , electron paramagnetic resonance , raman spectroscopy , spectroscopy , ground state , unpaired electron , singlet state , radical , ion , molecule , nuclear magnetic resonance , atomic physics , excited state , organic chemistry , physics , quantum mechanics , optics
Radical cations and dications of π‐conjugated systems play vital roles in organic electronic devices, organic conductors, and conducting polymers. Their structures, charge and spin distribution, and mechanism of charge transport are of great interest. In this article, radical cations and dications of a series of newly synthesized methylthio‐capped rylenes were synthesized and isolated. Their ground‐state structures, physical properties, and solid‐state packing were systematically investigated by various experimental methods, such as X‐ray crystallographic analysis, UV/Vis/NIR absorption spectroscopy, (spectro‐)electrochemistry, nuclear magnetic resonance spectroscopy, electron spin resonance spectroscopy, superconducting quantum interference device, and Raman spectroscopy, assisted by DFT calculations. It was found that all the charged species show an exceptional stability under ambient air and light conditions due to the efficient spin and charge delocalization over the whole rylene backbone. The dication of hexarylene turned out to have an unusual open‐shell singlet rather than closed‐shell ground state, thus it can be described as a diradical dication. Dimerization was observed for the radical cations and even the dications in crystals due to the strong intermolecular antiferromagnetic spin–spin interaction and π–π interaction, which result in unique magnetic properties. Such intermolecular association was also observed in solution.