Preresonance Raman studies of metal-to-ligand charge transfer in (NH sub 3 ) sub 4 Ru(2,2 prime -bpy) sup 2+. In situ bond length changes, force constants, and reorganization energies
- Northwestern Univ., Evanston, IL (USA)
As a prototype for charge-transfer reactions in general, the intense metal-to-ligand charge-transfer transition occurring in Ru(NH{sub 3}){sub 4}(bpy){sup 2+} (bpy = 2,2{prime}-bipyridine) has been examined experimentally by resonance and preresonance Raman spectroscopy and analytically by time-dependent scattering theory. To their knowledge, the present example represents the first application of the theory to charge-transfer problems. From the experiments and corresponding theory, the normal-coordinate changes accompanying the transition have been calculated. Both metal-ligand and intraligand bonds are found to distort significantly. When the distortion data are combined with the observed vibrational frequencies, a mode-by-mode assessment of the inner-shell reorganization energy is possible. Further experiments, in which the nature of the solvent is systematically varied, show that selected force constants (and therefore selected components of the internal reorganization energy) are modulated significantly (ca. 6-11 %) by ligand-solvent hydrogen bonding. Finally, variations in the nature of the solvent are found to shift ground- and/or excited-state energies in such a way as to either enhance or attenuate the occurrence of net photochemistry.
- DOE Contract Number:
- FG02-87ER13808
- OSTI ID:
- 7158889
- Journal Information:
- Journal of the American Chemical Society; (USA), Vol. 111:13; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
RUTHENIUM COMPLEXES
RAMAN SPECTRA
CHARGE TRANSPORT
CHEMICAL BONDS
DATA ANALYSIS
ELECTRON TRANSFER
EXPERIMENTAL DATA
MEASURING INSTRUMENTS
MEASURING METHODS
METALS
COMPLEXES
DATA
ELEMENTS
INFORMATION
NUMERICAL DATA
SPECTRA
TRANSITION ELEMENT COMPLEXES
360104* - Metals & Alloys- Physical Properties
400201 - Chemical & Physicochemical Properties