1620588-89-7Relevant academic research and scientific papers
Synthesis, structure, photochromism, mesogenic property and DFT computations of silver(I) complexes of long chain alkyl group containing 1-alkyl-2-(arylazo)imidazoles
Nandi, Avijit,Sen, Chandana,Roy, Suman,Mallick, Debasish,Sinha, Randhir,Mondal, Tapan Kumar,Sinha, Chittaranjan
, p. 186 - 196 (2014/06/23)
The complexes [Ag(Raai-CnH2n +1)2]ClO4 (where Raai-CnH 2n+1 refer to 1-alkyl-2-(arylazo)imidazoles; R = H, Me and n = 4-22 (even numbers)) have been characterized by spectroscopic studies (UV-Vis, FT-IR, 1H NMR). The X-ray structure of [Ag(Haai-C22H45)2]ClO4 confirms a distorted tetrahedral geometry. UV light irradiation (365-370 nm) of an acetonitrile solution of [Ag(Raai-CnH2n +1)2]ClO4 shows E-to-Z (trans-to-cis) isomerization of the coordinated Raai-CnH2 n+1 group. The reverse transformation, Z-to-E (cis-to-trans), is very slow upon visible light irradiation, but becomes significantly faster on increasing the temperature (298-313 K). The rates and quantum yields (φE→Z) of the E-to-Z isomerization of the free ligands are higher than those of the complexes, which have proved the effect of rotor volume, rotor mass and the 1-alkyl chain length (-C nH2n+1). [Ag(Haai-C 18H37)2]ClO4 shows a metallomesogenic property and undergoes phase transitions: the Cr (46.7 °C) - SmC (106.4 °C) - I phase sequence on heating and I (106.4 °C) - SmA (46.4 °C) - Cr on cooling. The SmC phase appears as the typical fan-shaped texture. DFT computations on the optimized structure were carried out to explain the spectral properties.
