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Toward Benzobis(thiadiazole)‐based Diradicaloids
Author(s) -
Liu Yi,
Phan Hoa,
Herng Tun Seng,
Gopalakrishna Tullimilli Y.,
Ding Jun,
Wu Jishan
Publication year - 2017
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201700732
Subject(s) - diradical , singlet state , triphenylamine , excited state , electron paramagnetic resonance , acetylene , photochemistry , chemistry , crystallography , population , triplet state , ground state , computational chemistry , materials science , atomic physics , nuclear magnetic resonance , organic chemistry , physics , demography , sociology
We theoretically predicted that acetylene‐bridged benzo[1,2‐ c ;4,5‐ c ′]bis[1,2,5]thiadiazole (BBT) oligomers would show a quick increase of diradical character with the extension of chain length. To validate the hypothesis, six stable BBT‐based diradicaloids were synthesized and fully characterized by X‐ray crystallographic analysis and various spectroscopic measurements. Three of them showed prominent paramagnetic activity at elevated temperatures due to thermal population from the open‐shell singlet ground state to triplet excited state. It was also found that substitution by electron‐donating triphenylamine groups at the termini promoted the diradical character and reduced the singlet–triplet energy gap, and at the same time, resulted in intense near‐infrared absorption.