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Title: Variable-temperature emission studies of solvation dynamics: Evidence for coupling of solvation to chromophore structural dynamics in the evolution of charge-transfer excited states

Abstract

Variable-temperature emission data over the range 90--298 K have been collected for a series of bipyridyl complexes of Ru{sup II}. Spectra obtained for [Ru(dmb){sub 3}]{sup 2+} (dmb = 4,4{prime}-dimethyl-2,2{prime}-bipyridine), [Ru(dpb){sub 3}]{sup 2+} (dpb = 4,4{prime}-diphenyl-2,2{prime}-bipyridine), [Ru(dotb){sub 3}]{sup 2+} (dotb = 4,4{prime}-di-o-tolyl-2,2{prime}-bipyridine), and [Ru(dmesb){sub 3}]{sup 2+} (dmesb = 4,4{prime}-dimesityl-2,2{prime}-bipyridine) in 4:1 EtOH/MeOH show similar trends in terms of both the red shift of the emission spectrum and the thermal breadth of the solvent response as the temperature is increased through the glass-to-fluid transition. In contrast, data collected in 2-MeTHF show a strong dependence on the identity of the chromophore, the details of the spectral evolution qualitatively correlating with changes in the steric demands of the system. The most dramatic effect is observed for [Ru(dmesb){sub 3}]{sup 2+}, in which there is an apparent change in the nature of the emitting species with increasing temperature. These observations suggest a strong coupling of solvation dynamics and solute structure in the low-temperature regime as well as at intermediate temperatures where the structure of the chromophore is evolving in the course of excited-state relaxation. The results underscore the potential importance of specific solvent-solute interactions in the dynamics of solvation for cases in which large-amplitude molecular motionmore » of the chromophore accompanies thermalization of the excited state.« less

Authors:
;
Publication Date:
Research Org.:
Univ. of California, Berkeley, CA (US)
Sponsoring Org.:
USDOE
OSTI Identifier:
20003188
DOE Contract Number:  
FG03-96ER14665
Resource Type:
Journal Article
Journal Name:
Inorganic Chemistry
Additional Journal Information:
Journal Volume: 38; Journal Issue: 19; Other Information: PBD: 20 Sep 1999
Country of Publication:
United States
Language:
English
Subject:
40 CHEMISTRY; RUTHENIUM COMPLEXES; BIPYRIDINES; SOLVATION; DYNAMICS; EMISSION SPECTRA; EXCITED STATES

Citation Formats

Damrauer, N.H., and McCusker, J.K. Variable-temperature emission studies of solvation dynamics: Evidence for coupling of solvation to chromophore structural dynamics in the evolution of charge-transfer excited states. United States: N. p., 1999. Web. doi:10.1021/ic990703l.
Damrauer, N.H., & McCusker, J.K. Variable-temperature emission studies of solvation dynamics: Evidence for coupling of solvation to chromophore structural dynamics in the evolution of charge-transfer excited states. United States. doi:10.1021/ic990703l.
Damrauer, N.H., and McCusker, J.K. Mon . "Variable-temperature emission studies of solvation dynamics: Evidence for coupling of solvation to chromophore structural dynamics in the evolution of charge-transfer excited states". United States. doi:10.1021/ic990703l.
@article{osti_20003188,
title = {Variable-temperature emission studies of solvation dynamics: Evidence for coupling of solvation to chromophore structural dynamics in the evolution of charge-transfer excited states},
author = {Damrauer, N.H. and McCusker, J.K.},
abstractNote = {Variable-temperature emission data over the range 90--298 K have been collected for a series of bipyridyl complexes of Ru{sup II}. Spectra obtained for [Ru(dmb){sub 3}]{sup 2+} (dmb = 4,4{prime}-dimethyl-2,2{prime}-bipyridine), [Ru(dpb){sub 3}]{sup 2+} (dpb = 4,4{prime}-diphenyl-2,2{prime}-bipyridine), [Ru(dotb){sub 3}]{sup 2+} (dotb = 4,4{prime}-di-o-tolyl-2,2{prime}-bipyridine), and [Ru(dmesb){sub 3}]{sup 2+} (dmesb = 4,4{prime}-dimesityl-2,2{prime}-bipyridine) in 4:1 EtOH/MeOH show similar trends in terms of both the red shift of the emission spectrum and the thermal breadth of the solvent response as the temperature is increased through the glass-to-fluid transition. In contrast, data collected in 2-MeTHF show a strong dependence on the identity of the chromophore, the details of the spectral evolution qualitatively correlating with changes in the steric demands of the system. The most dramatic effect is observed for [Ru(dmesb){sub 3}]{sup 2+}, in which there is an apparent change in the nature of the emitting species with increasing temperature. These observations suggest a strong coupling of solvation dynamics and solute structure in the low-temperature regime as well as at intermediate temperatures where the structure of the chromophore is evolving in the course of excited-state relaxation. The results underscore the potential importance of specific solvent-solute interactions in the dynamics of solvation for cases in which large-amplitude molecular motion of the chromophore accompanies thermalization of the excited state.},
doi = {10.1021/ic990703l},
journal = {Inorganic Chemistry},
number = 19,
volume = 38,
place = {United States},
year = {1999},
month = {9}
}