Abstract:
A series of novel chalcone based dipolar compounds having different arylamines (N, N dimethylaniline/triphenylamine/N-ethylcarbazole) or polyaromatic hydrocarbons (pyrene /anthracene) as donor, cyanovinyl unit as linker and/or acceptor and phenyl moiety at another end were synthesized and characterized in an attempt to unravel the effect of different donor unit as well as cyano substitution on optical, electrochemical and thermal properties. A model compound without cayno substitution was also synthesized for comparative analysis. They exhibited absorption peak around 359-447 nm attributed to transitions originated from delocalized ir-n* transitions and charge transfer transitions. Although the absorption spectra of the dyes were not significantly influenced by the nature of the solvents whereas, the fluorescence of chalcones was red-shifted to the range of 471-575 nm and was most intense in chloroform. The strong electron-attracting cyano group quenched the fluorescence in polar solvents. All the compounds were characterized by a quasi-reversible oxidation wave originated from the donor segment which underwent shift corresponding to electron-donating strength of donor moiety. The thermogravimetric analysis results indicate that cyano substitution is helpful in increasing the thermal stability
