DFT and ab initio calculations of the vibrational frequencies and visible spectra of triazenes derived from cyclic amines

We present a detailed analysis of the structural, infrared spectra and visible spectra of the 4-substituted aminoazo-benzenesulfonyl azides. The preparation of 4-sulfonyl azide benzenediazonium chloride with cyclic amines of various ring sizes (pyrrolidine, piperidine, 4-methylpiperidine, N-methylpiperazine, morpholine and hexamethyleneimine) have been investigated theoretically by performing HF and DFT levels of theory using the standard 6-31G* basis set. The optimized geometries and calculated vibrational frequencies are evaluated via comparison with experimental values. The vibrational spectral data obtained from solid phase FT-IR spectra are assigned modes based on the results of the theoretical calculations. The observed spectra are found to be in good agreement with the calculations.