Excited-state electron transfer in a chromophore-quencher complex. Spectroscopic identification of a redox-separated state
- Univ. Catolica de Chile, Santiago (Chile). Facultad de Quimica; and others
The authors report herein the first photophysical studies on Re complexes. In the chromophore-quencher complex fac-[Re(Aqphen)(CO){sub 3}(py-PTZ)]{sup +} (Aqphen is 12,17-dihydronaphtho[2,3-h]dipyrido[3,2-a:2{prime}3{prime}-c]-phenazine-12,17-dione; py-PTZ is 10-(4-picolyl)phenothiazine). Aqphen is a dppz derivative, containing a pendant quinone acceptor at the terminus of a rigid ligand framework. Quinone acceptors are used widely in studies of photoinduced electron and energy transfer. This introduces a derivative third, low-lying, ligand-based {pi}{sup *} acceptor level localized largely on the quinone fragment. Laser flash excitation of fac-[Re(Aqphen)(CO){sub 3}(py-PTZ)]{sup +} (354.7 nm; in 1,2-dichloroethane) results in the appearance of a relatively long-lived transient that decays with {tau}{sub 298K} = 300 ns (k = 3.3 {times} 10{sup 6} s{sup {minus}1}). Application of transient absorption, time-resolved resonance Raman, and time-resolved infrared spectroscopies proves that this transient is the redox-separated state fac-[Re{sup I}(Aqphen{sup {sm_bullet}{minus}})(CO){sub 3}(py-PTZ{sup {sm_bullet}+})]{sup +} in which the excited electron is localized largely on the quinone portion of the Aqphen ligand.
- Sponsoring Organization:
- National Science Foundation, Washington, DC (United States); USDOE, Washington, DC (United States)
- OSTI ID:
- 682139
- Journal Information:
- Inorganic Chemistry, Journal Name: Inorganic Chemistry Journal Issue: 12 Vol. 38; ISSN 0020-1669; ISSN INOCAJ
- Country of Publication:
- United States
- Language:
- English
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