RAMAN-SPECTROSCOPIC STUDY OF 1-METHYL-2(1H)-PYRIDINIMINE, THE DEUTERATED ANALOG, AND 1-METHYL-2(1H)-PYRIDINONE

Band assignments of the Raman spectra of 1-methyl-2(1H)pyridinimine (1 -MPI), its deuterated analog (1-MPI-d), and 1-methyl-2(IH)pyridinone ( 1-MPD) in CCl4 and those of the neat liquid have been carried out on t he basis of the previously reported IR spectrum, normal coordinate tre atment of vibrational frequencies and intensities of I-MPI and 1-MPI-d The observed Raman spectra of these compounds are in fairly good agre ement with the calculated vibrational frequencies. The Raman band at a bout 1650 cm(-1) for 1-MPI (and I-MPI-d) and 1-MPD, which is assigned to stretching-modes of the C=N and ring C=C: bonds and to stretching m odes of the C=O and ring C=C bonds, respectively, becomes almost Raman -inactive, even though these bands are infrared-active. The band of lo west frequency in the observed Raman spectra of I-MPI, I-MPI-d, and 1- MPD appears at about 100 cm(-1). It is assigned to the torsional motio n of the CR, group. In the neat liquid, 1-MPI and 1-MPI-d form an inte rmolecular hydrogen bond between the imino groups. (C) 1998 Elsevier S cience B.V. All rights reserved.