Influence of anion on the quadratic nonlinearity and depolarization ratios of scattered second harmonic light from cation-pi complexes


Autoria(s): Ramasesha, S; Mukhopadhyay, S; Pandey, Ravindra; Das, Puspendu K; Zyss, Joseph
Data(s)

17/05/2012

Resumo

We have investigated quadratic nonlinearity (beta(HRS)) and linear and circular depolarization ratios (D and D', respectively) of a series of 1:1 complexes of tropyliumtetrafluoroborate as a cation and methyl-substituted benzenes as pi-donors by making polarization resolved hyper-Rayleigh scattering measurements in solution. The measured D and D' values are much lower than the values expected from a typical sandwich or a T-shaped geometry of a complex. In the cation-pi complexes studied here, the D value varies from 1.36 to 1.46 and D' from 1.62 to 1.72 depending on the number of methyl substitutions on the benzene ring. In order to probe it further, beta, D and D' were computed using the Zerner intermediate neglect of differential overlap-correction vector self-consistent reaction field technique including single and double configuration interactions in the absence and presence of BF4- anion. In the absence of the anion, the calculated value of D varies from 4.20 to 4.60 and that of D' from 2.45 to 2.72 which disagree with experimental values. However, by arranging three cation-pi BF4- complexes in a trigonal symmetry, the computed values are brought to agreement with experiments. When such an arrangement was not considered, the calculated beta values were lower than the experimental values by more than a factor of two. This unprecedented influence of the otherwise ``unimportant'' anion in solution on the beta value and depolarization ratios of these cation-pi complexes is highlighted and emphasized in this paper. (C) 2012 American Institute of Physics. http://dx.doi.org/10.1063/1.4716020]

Formato

application/pdf

Identificador

http://eprints.iisc.ernet.in/44692/1/AIP_JOU_CHE_PHY_136-19_2012.PDF

Ramasesha, S and Mukhopadhyay, S and Pandey, Ravindra and Das, Puspendu K and Zyss, Joseph (2012) Influence of anion on the quadratic nonlinearity and depolarization ratios of scattered second harmonic light from cation-pi complexes. In: JOURNAL OF CHEMICAL PHYSICS, 136 (19).

Publicador

AMER INST PHYSICS

Relação

http://dx.doi.org/10.1063/1.4716020

http://eprints.iisc.ernet.in/44692/

Palavras-Chave #Inorganic & Physical Chemistry #Solid State & Structural Chemistry Unit
Tipo

Journal Article

PeerReviewed