NLOphoric multichromophoric auxiliary methoxy aided triphenylamine D-π-A chromophores - Spectroscopic and computational studies

Molecules containing methoxy supported triphenylamine as strong electron-donor and dicyanovinyl as electron-acceptor groups interacting via isophorone as a configurationally locked polyene pi-conjugated bridge are studied for their nonlinear optical properties. The photophysical study of examined chromophores in non-polar and polar solvents suggest that they exhibit strong emission solvatochromism and significant charge transfer characteristics supported by Lippert-Mataga plots and Generalised Mulliken Hush analysis. Linear and nonlinear optical properties as well as electronic properties measured by spectroscopic methods and cyclic voltametry and supported by DFT calculation were used to elucidate the structure property relationships. All three chromophores exhibit very high thermal stabilities with the decomposition temperatures higher than 340 degrees C. The vibrational motions play very important role in determining the overall NLO response styryl chromophores which was established by INT study. Dye 3 with maximum nonlinear optical susceptibility among three D-pi-A systems proves that the multi-branched push-pull chromophores exhibit a higher third order nonlinear susceptibility and justifies the design strategy. (C) 2017 Elsevier B.V. All rights reserved.