VIBRATIONAL-SPECTRA OF 2,6-DIPHENYL PYRIDINE, 2,2'-6',2''-TERPYRIDINEAND META-TERPHENYL

The Raman and infrared spectra of 2,6-diphenyl pyridine, m-terphenyl a nd 2,2':6',2''-terpyridine have been analysed as metadisubstituted ben zene or pyridine molecules. Complete vibrational assignment shows that some modes in the case of internal vibrations of substituents appear in pairs. The splitting of these modes have been attributed to the in- and out-of-phase motions arising out of interaction between phenyl or pyridine rings, as the case may be. In the case of meta terphenyl and terpyridine, two probable cases of Fermi resonance have been observed .