Picosecond–nanosecond time-resolved resonance Raman study of the structure and dynamics of the excited states of 5-dibenzosuberene derivatives

✍ Scribed by Makoto Sakai; Misao Mizuno; Hiroaki Takahashi

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 325 KB
• Volume: 29
• Category: Article
• ISSN: 0377-0486
• DOI: 10.1002/(sici)1097-4555(199810/11)29:10/11<919::aid-jrs333>3.0.co;2-p

✦ Synopsis

Structures and dynamics of the excited electronic states, and and cation radical of 5-dibenzosuberene S 1 T 1 , R ' (DBCH) and its derivatives were investigated in the picosecond-nanosecond time domain using time-resolved resonance Raman spectroscopy with the aid of time-resolved absorption spectroscopy. For both 5-dibenzosuberene and 5-dibenzosuberenol (DBCH-5-ol) the e †ect of vibrational cooling or vibrational relaxation in was detected in S 1 both the Raman and absorption spectra in the 0-40 ps time region ; the time constant of this e †ect was estimated to be about 13 ps for both DBCH and DBCH-5-ol. The expected conformational change in the state of S 1 DBCH-5-ol was not clearly observed in the resonance Raman spectra. It was observed, however, that the central ethylenic CxC bond was weakened considerably in but the degree of the weakening was considerably less than S 1 , that of and was very similar to that of The dynamics of of 5-dibenzosuberenone were complicated, T 1 R'~. S 1 possibly owing to the existence of a carbonyl group, and are not discussed.