Photoinduced intramolecular electron transfer in 1,2,4,5,-tetrakis(diphenylphosphino)benzene-bridged Os{sup II}-M{sup II} dimetallic complexes (M = Ni, Pd, Pt)
- Univ. of Texas, Austin, TX (United States)
Emission quantum yields observed for the dimetallic complexes [(bpy){sub 2}Os{sup II}-(tppb)-M{sup II}(dppb)] (M = Ni, Pd, Pt) and [(bpy){sub 2}Os{sup II}-(bpy){sub 2}](bpy = 2,2{prime}-bipyridine; dppb = 1,2-bis(diphenylphosphino)benzene; tppb = 1,2,4,5-tetrakis (diphenylphosphino)benzene) reflect substantial intramolecular interaction between the component metal centers in the excited states of these complexes. The slightly shifted redox potentials and absorption spectra of the dimetallic complexes, in comparison with their monometallic models, [Os{sup II}(bpy){sub 2}(dppb)] and [M{sup II}(dppb){sub 2}](M = Ni, Pd, Pt), are consistent with modest interactions in the ground states of these complexes, as has been observed for the analogous Ni{sup II} dimetallic complexes. The quantum yields ({phi} = 0.002) and excited state lifetimes ({tau} = 9-12 ns) of the dimetallic complexes [(bpy){sub 2}Os{sup II}-(tppb)-M{sup II}(dppb)](M = Ni, Pd) were lower and shorter than those of [Os{sup II}(bpy){sub 2}(dppb)]({phi} = 0.049, {tau} = 270 ns), as is consistent with quenching of the Os{sup II} MLCT state by the second metal center. The apparent intramolecular electron transfer rate constants (k{sub et}=3 x 10{sup 5}-1 x 10{sup 8} s{sup {minus}1} for the excited states of the dimetallic complexes [bpy){sub 2}Os{sup II}-(tppb)-M{sup II}(dppb)](M = Ni, Pd, Pt) correlate with calculated driving forces for electron transfer from Os{sup II} to M{sup II}(M = Ni, Pd, Pt).
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 457127
- Journal Information:
- Inorganic Chemistry, Journal Name: Inorganic Chemistry Journal Issue: 1 Vol. 34; ISSN 0020-1669; ISSN INOCAJ
- Country of Publication:
- United States
- Language:
- English
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