Investigation of the excited state structure of DCM via ultrafast electronic pump/vibrational probe

Aaron J Van Tassle; Matthew A Prantil; Graham R Fleming

doi:10.1021/jp0603738

Investigation of the excited state structure of DCM via ultrafast electronic pump/vibrational probe

J Phys Chem B. 2006 Sep 28;110(38):18989-95. doi: 10.1021/jp0603738.

Authors

Aaron J Van Tassle¹, Matthew A Prantil, Graham R Fleming

Affiliation

¹ Department of Chemistry, University of California, Berkeley, and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.

PMID: 16986894
DOI: 10.1021/jp0603738

Abstract

Time resolved visible pump, infrared probe transient absorption measurements of the solutes 4-dicyanomethylene-2-methyl-6-(p-(dimethylamino)styryl)-4H-pyran (DCM) and its isotopomer DCM-d6 are employed to probe the dynamics of charge transfer state formation in dimethyl sulfoxide (DMSO) and acetonitrile (MeCN). We observe a two stage charge transfer (CT): the first step is an instrument-response-limited charge separation to the dicyanomethylene group, and the second involves a structural evolution of the dimethylamino group. Theoretical calculations and isotopic substitution indicate that the observed vibration is due to the dimethylamino group twisting out of plane, stabilizing the charge separation.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Acetonitriles
Dimethyl Sulfoxide
Electrons*
Models, Molecular
Molecular Structure
Pyrans / chemistry*
Spectroscopy, Fourier Transform Infrared*
Styrenes / chemistry*
Time Factors

Substances

Acetonitriles
Pyrans
Styrenes
4-(dicyanomethylene)-2-methyl-6-(4-(dimethylamino)styryl)-4H-pyran
Dimethyl Sulfoxide
acetonitrile