Quantification of the push-pull character of the isophorone chromophore as a measure of molecular hyperpolarizability for NLO applications

摘要

The push-pull character of a series of para-phenyl substituted isophorone chromophores has been quantified by the I3C chemical shift difference of the three conjugated partial C=C double bonds and the quotient of the occupations of both the bonding and anti-bonding orbitals of these C=C double bonds as well.The correlations of the two push-pull quantifying parameters,and to the corresponding bond lengths,strongly recommend pi*C_C/piC=C as the general parameter to estimate charge alternation and as a very useful indication of the molecular hyperpolarizabilities for NLO application of the compounds studied.