Abstract
This paper deals with the influence of various electron acceptors, which contain at least two cyano groups (obtained from reactions with malononitrile, tetracyanoethene, tetracyanoquinodimethane, dimeric malononitrile), on the generation of second harmonic light of donor–acceptor-substituted anilines. For EFISH measurements, which were performed on solutions in 1,4-dioxane and acetone a Yag–Nd laser was used. The influence of the solvent on the SHG efficiency is discussed shortly and compared to solvatochromic effects. The measurement data were corrected for absorptive effects so that absorbing compounds can be compared to non-absorbing ones. Increasing the acceptor strength not only bathochromically shifted the longest wavelength UV–vis absorption band but also leaded to an enhancement of μβ-values obtained by the EFISH measurements. Trends of hyperpolarizabilities calculated by semi-empirical molecular orbital methods by and large conformed those found experimentally.
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