Semiempirical infrared spectra simulations for some aromatic amines of interest for azo dye chemistry

A set of semiempirical methods (PM3, AM1, MNDO, MNDO3, INDO, CNDO and ZINDO /1) has been tested to find the best tool for the identification of aromati c amines by infrared spectroscopy. Analysed were 1,4-, 1,3-, 1,2-phenylened iamines and aniline, amines commonly used in the dye industry. Of all the s emiempirical methods tested. AMI showed the closest correspondence to exper imental values. It provided the best linearity between the calculated and e xperimental frequencies (correlation coefficient, cc = 0.9993). In the rang e of -NH2 stretching vibrations. the best correspondence between the theore tical and experimental frequencies was achieved for the PM3 method (cc = 0. 8369). (C) 2001 Elsevier Science B.V. All rights reserved.