Resonance Raman Spectroscopic Studies of trans-Dioxorhenium(V) tetrapyridyl Species
Abstract
Resonance Raman spectra for several trans-dioxorhenium(V)tetrapyridyl species have been obtained. Excitation in the visible region (ligand-field (L-F) absorption) leads to modest enhancement of Raman scattering, chiefly for metal- oxo modes. The observations are qualitatively, consistent with an earlier luminescence study (Winkler, Gray, J. Am. Chem. Soc. 1985, 24, 346) which clearly demonstrated that L-F excitation induces displacements in O=Re=O coordinates. Excitation in the near LTV leads to much stronger scattering, but only for pyridyl and metal-pyridyl vibrations; metal-oxo scattering is essentially absent. These experiments clearly establish the metal-to-pyridine charge-transfer nature of the intense near-LTV absorption. They also reinforce the assignment of dxy (orthogonal to the O=Re=O core) as the sole occupied d orbital in the ground-state species. In this respect, the trans complexes contrast with related cis species for which p(oxo) orbitals must interact with all three (Re) orbitals, and for which substantial v (O=Re=O) enhancement upon charge-transfer excitation is therefore observed. Finally, this report corrects an earlier observation elsewhere in which normal Raman scattering from solvent (CH3CN) was mistakenly ascribed to scattering from trans-dioxorhenium(V) tetrapyridine.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 28, 1992
- Accession Number
- ADA249919
Entities
People
- Carolyn Mottley
- Christopher S. Johnson
- Gerald D. Danzer
- Joseph T. Hupp
Organizations
- Northwestern University