Synthesis, theoretical characterisation and spectra of thiophene-fluorene π-conjugated derivatives

The syntheses, spectral measurements and the theoretical study of 2-((9H-fluoren-9-ylidene)methyl)thiophene (A), ((9H-fluoren-9-ylidene)methyl)-5-(thiophen-2-yl)thiophene (B), 1-(5-((9H-fluoren-9-ylidene)methyl)thiophen-2-yl)propan-1-one (C), 1- (5-((9H-fluoren-9-ylidene)methyl)thiophen-2-yl)pentan-1-one (D), 1,2-bis(1-(5-((9H-fluoren-9-ylidene) methyl)thiophen-2-yl)propylidene)hydrazine (E) and 1,2-bis(1-(5-((9H-fluoren-9-ylidene)methyl)thiophen-2-yl)pentylidene)hydrazine (F) are presented. The electron absorption and fluorescence spectra of prepared molecules are measured in polymer matrix and solution. The influence of the conformation (e.g. cis- and trans-forms in the case of E and F molecules) on electronic spectra are interpreted by ZINDO/S method. Our results indicate that the thiophene rings connected with terminal fluorene chromophores through the double bounded carbon atom seem to be suitable candidates for the subsequent preparation of the electro-optical materials.