Synthesis, electrochemistry and liquid crystal properties of 1,2,3-(NH)-triazolylferrocene derivatives

A series of aryl(5-ferrocenyl-2H-1,2,3-triazol-4-yl)methanone 3a-3d have been firstly synthesized and characterized. The X-ray crystal structure of phenyl(5-ferrocenyl-2H-1,2,3-triazol-4-yl)methanone 3a confirms that 1,2,3-triazole ring exists in the crystal as the 2H isomer form. The UV-vis absorption spectra of these compounds correspond to the assembled spectra of ferrocene and aryl substitute groups, and the fluorescence spectra show a maximum at 374 nm in CH2Cl2. The cyclic voltammograms of 3b-3d show the reversible oxidation waves of the ferrocenyl groups, and these waves anodically shift in comparison with ferrocene standard due to the electron withdrawing effect of the 1,2,3-triazoles ring. According to thermal polarizing microscopy and differential scanning calorimetry studies, compounds 3b-3d display liquid crystal behaviors over wider mesophase range during first heating. (C) 2013 Elsevier B.V. All rights reserved.