Time-resolved resonance Raman and molecular orbital studies of the structures of the transient species involved in the photochromic reaction of 2, 2′-spirobi [2H-1- …
Abstract Resonance Raman spectra of the transient species of 2, 2′-spirobi [2H-1- benzopyran] in various solvents reveal that at least two isomers exist in solution, the relative abundance of which depends on the polarity and hydrogen-bond donor ability of the solvent. Vibrational assignment of the transient species based on 13 C substitutions shows that the Raman bands mainly attributable to the vibrations of the open benzopyran part are ...