Structure correlation of silylated dicarboxylic acid monomer and its respective oligomeric polyamide-imide using experimental and theoretical vibrational spectra

Correlation between theoretical and experimental (infrared and Raman spectroscopies) vibrational spectra of two compounds, both with a silyl group present in their main chain and with an optically active structure (L-valine) as side group, was performed. These compounds are based in a chiral dicarboxylic acid monomer and its respective polyamide-imide, oligomer that was previously synthesized by a direct polycondensation. Spectra were recorded in the region comprised between 500 and 4000?cm^?1 for infrared and Raman analysis. The Raman spectra were obtained through a 1064?nm laser as excitation source.

Theoretical models were carried out in order to find the optimal molecular geometry of the analyzed systems, with a complete assignment of their vibrational spectra. The Raman experimental data obtained with a Nd:YAG laser for this kind of silylated organic compounds, and the comparison between these results with the theoretical data is a useful advance in the polymer synthesis field, which can be used as reference for subsequent studies.