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1528068 
Journal Article 
Modulation of the second-order nonlinear optical properties of the two-dimensional pincer Ru(II) complexes: substituent effect and proton abstraction switch 
Wang, CH; Ma, NN; Sun, XX; Sun, SL; Qiu, YQ; Liu, PJ 
2012 
1 
Journal of Physical Chemistry A
ISSN: 1089-5639
EISSN: 1520-5215 
116 
43 
10496-10506 
English 
23050877 
WOS:000310482500004 
The static second-order nonlinear optical (NLO) properties on a series of the two-dimensional (2D) pincer Ru(II) complexes with the substituted Tpy and H(2)SCS tridentate ligands (Tpy = 2,2':6',2″-terpyridyl and H(2)SCS = 2,6-bis(benzylaminothiocarbonyl)phenyl) have been investigated by density functional theory (DFT). Introducing different donor/acceptor substituents to two ligands has an influence on the static first hyperpolarizabilities (β(tot)) of the 2D systems. Compared to the reference system 1 [Ru(H(2)SCS)(Tpy)](+), introducing the branches with strong electron acceptor group (p-NO(2)-phenylethynyl) to the Tpy ligand or the branches with strong electron donor group (p-NH(2)-phenylethynyl) to the H(2)SCS ligand can effectively improve the β(tot) values. Time-dependent DFT (TDDFT) calculations indicate that the enhanced β(tot) values of the substituted systems are dominated by the intraligand charge transfer (ILCT), metal-to-ligand charge transfer (MLCT) and ligand-to-metal charge transfer (LMCT) transitions. Furthermore, the proton abstraction plays an important role in tuning the second-order NLO response. Particularly, for system 5 bearing the branches with NO(2) groups on H(2)SCS ligand, there is a dramatic enhancement in the β(tot) values for its deprotonated forms. The β(tot) values of the monodeprotonated system 5-H and the dideprotonated system 5-2H (58.712 × 10(-30) and 761.803 × 10(-30) esu) are about 7.58 times and 36.4 times larger than their diprotonated system 5, respectively. The second-order NLO responses based on substituent effect and proton abstraction switch are two-dimensional in characteristic with the large off-diagonal tensor values.