Journal of Physical Chemistry, Vol.99, No.2, 531-537, 1995
Laser-Induced Fluorescence of Rhenocene in Low-Temperature Matrices - Selective Excitation and Emission
Rhenocene, Re(eta(5)-C5H5)(2), has been generated by photolysis of Re(eta(5)-C5H5)(2)H isolated in nitrogen and argon matrices at 12 K, and has been studied by laser-induced fluorescence with a pulsed tunable laser. The emission lifetime of the lowest LMCT excited state is (71.9 +/- 1.3) ns in nitrogen and (69.3 +/- 1.4) ns in argon matrices. The emission and excitation spectra are far simpler and much better resolved than the UV/vis absorption spectrum, because the laser selects individual sites/conformers in the matrix (or groups of sites with very similar absorptions). Vibrational progressions are detected which are based on the ring-metal-ring stretching mode, nu(3), and combinations of that mode with the symmetric ring breathing mode, nu(2), and the symmetric C-H deformation mode, nu(3). In the LMCT excited state, there is an increase in nu(4) of 5% and a decrease in nu(3) (9%) and nu(2) (3%), consistent with transfer of an electron from a ligand pi-orbital to a metal-ligand bonding orbital.
Keywords:MAGNETIC CIRCULAR-DICHROISM;ORGANOMETALLIC COMPLEXES;ELECTRONIC SPECTROSCOPY;CYCLOPENTADIENYL COMPLEXES;METALLOCENES;LUMINESCENCE;RUTHENOCENE;(ETA-5-C5ME5)2RE;SPECTRA;STATES