Raman spectroscopic and structural investigation of 1,4-diphenylbuta-1,3-diene and selected monomethyl and dimethyl substituted homologues

The Raman and mass spectra of 1,4-diphenylbuta-1,3-diene and several of its monomethyl and dimethyl homologues are reported and discussed, with a view to developing a spectroscopic protocol for detecting the presence and position of a methyl group in these compounds. Raman spectroscopy and mass spectrometry are shown to provide complementary information, by which the four available monomethyl homologues may be readily distinguished from each other and 1,4-diphenylbuta-1,3-diene itself. The utility of these 1,4-diarylbutadienes as model compounds for carotenoids and related materials, which may serve as indicators of extinct or extant extraterrestrial life, is considered.