Application of time-resolved, step-scan fourier transform infrared spectroscopy to excited-state electronic structure in polypyridyl complexes of rhenium(I)
- Los Alamos National Lab., NM (United States); and others
Recent advances in transient infrared spectroscopy have provided the means for infrared measurements to be made following laser excitation on short time scales. The infrared technique is particularly valuable in the study of metal complexes containing CO or CN{sup -} because v(CO) and v(CN) stretching vibrations have high oscillator strengths and the sensitivities of their energies and bandwidths to electronic and molecular structure are well established. Electronic excitation generally produces significant transient infrared absorption changes which are intense and characteristic of the changes in electron structure between states. For example, in [(phen)-(CO){sub 3}Re(NC)Ru(bpy){sub 2}(CN)]{sup +} (phen is 1,10-phenanthroline; py is 2,2{prime}-bipyridine) Re{sup I}(d{pi}) {yields} phen({pi}*) excitation produces initially a Re{sup II}(phen{sup *-}) metal-to-ligand charge transfer (MLCT) excited state and large shifts in v(CO) (40-80 cm{sup -1}) compared to those in the ground state. Subsequently, rapid cross-bridge energy transfer occurs (k{sub q} {approximately} 2 x 10{sup 11} s{sup -1}) to give [(phen)-(CO){sub 3}Re{sup I}(NC)Ru{sup III}(bpy{sup *-})(CN)]{sup +*} which is accompanied by a shift of +57 cm{sup -1} in the terminal v(CN) band and only a slight shift in v(CO) compared to the ground state. Here, the authors apply step-scan transient infrared to the elucidation of the excited-state electronic structure in complexes.
- DOE Contract Number:
- FG05-86ER13633
- OSTI ID:
- 240971
- Journal Information:
- Inorganic Chemistry, Vol. 35, Issue 2; Other Information: PBD: 17 Jan 1996
- Country of Publication:
- United States
- Language:
- English
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