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Tuning Nonlinear Optical Properties by Altering the Diradical and Charge‐Transfer Characteristics of Chichibabin's Hydrocarbon Derivatives
Author(s) -
Fukuda Kotaro,
Suzuki Yuta,
Matsui Hiroshi,
Nagami Takanori,
Kitagawa Yasutaka,
Champagne Benoît,
Kamada Kenji,
Yamamoto Yohsuke,
Nakano Masayoshi
Publication year - 2017
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201601226
Subject(s) - diradical , hyperpolarizability , singlet state , chemistry , chemical physics , electronic structure , resonance (particle physics) , computational chemistry , charge (physics) , open shell , photochemistry , molecule , atomic physics , organic chemistry , polarizability , physics , quantum mechanics , excited state
Heteroatomic derivatives of Chichibabin's hydrocarbon are explored theoretically to highlight the relationship between the electronic structure and nonlinear optical (NLO) properties. The results show that the systems are divided into two classes: one that has intermediate electronic structure between two main contributing resonance structures, and a second with an electronic structure that is approximated by only one resonance structure. It is found that the former class of derivatives exhibits approximately one‐order larger static second hyperpolarizability ( γ ) than the latter class, because of either their intermediate diradical or charge‐transfer (CT) characteristics. The asymmetric systems are further scrutinized by using the static electric field model, which shows that the intermediate CT character is essential for the very large enhancement of γ in the asymmetric systems. These results not only clarify the structure–property relationships of open‐shell singlet NLO compounds with redox switching properties, but also shed light on a new and unexplored class of closed‐shell NLO systems generated by the introduction of intermediate CT nature into open‐shell singlet systems.