Spectroscopic study of the phase transitions of copper(II) n-alkanoates

Article abstract of DOI:10.1016/0584-8539(94)00128-X

FTIR spectra of copper nonanoate, decanoate, undecanoate and dodecanoate are recorded every 5 K from room temperature to 390 K.Changes detected in the infrared spectra when heating the sample allow the heat absorptions observed in some of these samples prior to the transition to the mesophase to be explained as due to conformational changes taking place in the alkyl chain next to the carboxylate group.Low frequency infrared and Raman spectra are consistent with a D_4h geometry for the ionic core where the copper ions are located.Moreover, the study of the low frequency region at the temperature of the mesophase permit the detection of rearrangement around the central core in the transition from the crystal to the mesophase.