Theoretical study on second hyperpolarizabilities of singlet diradical square planar nickel complexes involving o-semiquinonato type ligands

Hitoshi Fukui, Ryohei Kishi, Takuya Minami, Hiroshi Nagai, Hideaki Takahashi, Takashi Kubo, Kenji Kamada, Koji Ohta, Benoît Champagne, Edith Botek, Masayoshi Nakano

Research output: Contribution to journalArticlepeer-review

54 Citations (Scopus)

Abstract

Hybrid density functional theory method is applied for investigating the diradical character dependence of the second hyperpolarizability (γ) of square planar nickel complexes involving several types of bidentate ligands [o-C6H4XY, where X = Y = O, NH, S, Se, and PH as well as (X, Y) = (NH, NH2) and (S, NH2)]. It is found that, as a function of the donor atoms, the diradical character of these complexes varies from 0.0 to 0.884 and is associated with substantial variations of γ ranging from 14 × 103 to 819 × 103 au. In particular, the largest γ values are associated with intermediate diradical characters in good agreement with the structure-property relationship obtained for pure hydrocarbon systems. Increasing the electronegativity of the X and Y donor groups of the ligands leads to larger diradical characters as a result of the enhancement of the double bond nature of the C=X(Y) bonds, which further stabilizes the diradicals on both-end benzene rings. This demonstrates that the electronegativities of the donor atoms of the ligands become a tuning parameter of the diradical character and then of the γ values of these complexes.

Original languageEnglish
Pages (from-to)8423-8429
Number of pages7
JournalJournal of Physical Chemistry A
Volume112
Issue number36
DOIs
Publication statusPublished - 2008 Sep 11
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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