Picosecond Time-Resolved Resonance Raman Probing the Light Switch States of [Ru(Phen)2dppz]2+
Journal article, 2001

Picosecond time-resolved resonance Raman (picosecond-TR3) spectroscopy has been used to conduct an extensive photophysical characterization of the "light- switch" complex [Ru(phen)(2)dppz](2+) as a function of environment, in which studies have been carried out in aqueous and nonaqueous media and in DNA. The results are considered in rotation to a previous report describing "environment-sensitive" lowest triplet MLCT states. Vibrational marker features and enhancement patterns were used to determine the rapid progression (< 20 ps) between two triplet MLCT states in aqueous environment, followed by subnanosecond, nonradiative deactivation to the ground state. In nonaqueous environment, the long-lived, emissive triplet MLCT state is spectrally identified as the short-lived first triplet MLCT state observed in water, in agreement with the earlier proposed mechanism. The present data are shown to correlate well with previous nanosecond RR findings for the complex in each environment. Interestingly, a "precursor state" has been identified upon excitation in both nonaqueous solvent and in DNA, which precedes the triplet MLCT state, and the lifetime of which appears to be environment dependent. Observation of this state is discussed in relation to other recent femtosecond spectroscopic studies on this complex.

Author

C.G. Coates

Johan Olofsson

Department of Physical Chemistry

M. Coletti

J. McGarvey

Björn Önfelt

Department of Physical Chemistry

Per Lincoln

Department of Physical Chemistry

Bengt Nordén

Department of Physical Chemistry

Eimer Tuite

Department of Physical Chemistry

P. Matousek

A. Parker

Journal of Physical Chemistry B

1520-6106 (ISSN) 1520-5207 (eISSN)

Vol. 105 50 12653-12664

Areas of Advance

Nanoscience and Nanotechnology

Energy

Life Science Engineering

Materials Science

Subject Categories

Physical Chemistry

Roots

Basic sciences

DOI

10.1021/jp0127115

More information

Created

10/7/2017