Vibronic Spinndash;Orbit Interactions in Heteroaromatic Molecules. II. Phosphorescence of Quinoxaline and Other Diazanaphthalenes

摘要

Solvent effects on phosphorescence and its polarization characteristics indicate that the two major spinndash;orbit coupling mechanisms through which the3B2lpar;pgr;pgr;*rpar;state of quinoxaline acquires dipolehyphen;allowed character vianpgr;*states are1B1lpar;npgr;*rpar;thinsp;harr;thinsp;so3B2lpar;pgr;pgr;*rpar;and1A1lpar;pgr;pgr;*rpar;thinsp;harr;thinsp;b1vib1B1lpar;npgr;*rpar;thinsp;harr;thinsp;so3B2lpar;pgr;pgr;*rpar;.The deuterium isotope effect on the emission characteristic and the intensity of vibronic bands of thenrarr;pgr;*absorption suggest that the perturbing vibration(s) is an outhyphen;ofhyphen;plane Csngbnd;H bending mode(s).