Time-resolved resonance Raman study of the. delta. delta. * excited state of Re sub 2 Cl sub 8 sup 2 minus and Re sub 2 Br sub 8 sup 2 minus

Journal Article · Wed Mar 06 00:00:00 EST 1991 · Inorganic Chemistry; (United States)

DOI:https://doi.org/10.1021/ic00005a039· OSTI ID:5900485

Schoonover, J R; Dallinger, R F; Killough, P M; Sattelberger, A P; Woodruff, W H ^[1]

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1. Los Alamos National Lab., NM (United States)

Time-resolved resonance Raman (TR{sup 3}) spectra have been obtained for Re{sub 2}X{sub 8}{sup 2{minus}} (X = Cl, Br) in the A{sub 2u} ({delta}{delta}*) electronically excited state, at ambient temperature in solution. The Tr{sup 3} spectra exhibit Raman peaks that are assigned to the three symmetric vibrations of the excited state: the Re-Re stretch, Re-X stretch, and the Re-Re-X deformation. In addition, a depolarized peak attributed to an asymmetric X-Re-X bend is observed. Comparison of the TR{sub 3} results to single-crystal vibronic spectra reported by others clearly shows the effects of crystal constraints and observation time scale upon the strucutre of the {delta}{delta}* excited state. The TR{sup 3} data, obtained in solution on the nanosecond time scale, indicate that the excited state relaxes to a staggared molecular structure (D{sub 4} or D{sub 4d} symmetry). The vibronic data, obtained on single crystals under cryogenic conditions, are consistent with an eclipsed (D{sub 4h}) structure, similar to that of the ground state. A comparative TR{sup 3} study of quadruply bonded complexes, including both octahalodirhenate ions and Mo{sub 2}(PMe{sub 3}){sub 4}Cl{sub 4} (which is precluded by steric factors from significant torsional distorition about the metal-metal bond), was essential in elucidating the excited-state structures.

• OSTI ID: 5900485
• Journal Information: Inorganic Chemistry; (United States), Vol. 30:5; ISSN 0020-1669
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
RHENIUM BROMIDES
EXCITED STATES
RHENIUM CHLORIDES
EXPERIMENTAL DATA
RAMAN SPECTRA
BROMIDES
BROMINE COMPOUNDS
CHLORIDES
CHLORINE COMPOUNDS
DATA
ENERGY LEVELS
HALIDES
HALOGEN COMPOUNDS
INFORMATION
NUMERICAL DATA
REFRACTORY METAL COMPOUNDS
RHENIUM COMPOUNDS
RHENIUM HALIDES
SPECTRA
TRANSITION ELEMENT COMPOUNDS
400201* - Chemical & Physicochemical Properties