Photoinduced organic donor to metal electron transfer across a rigid spacer

• Published in: Journal of physical chemistry (1952) Vol. 94; no. 25; pp. 8745 - 8748
• Main Authors: Perkins, Thomas A, Hauser, Brian T, Eyler, John R, Schanze, Kirk S
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01.12.1990
• Subjects: 400201 - Chemical & Physicochemical Properties; 400500 - Photochemistry; ABSORPTION SPECTROSCOPY; AZINES; BIPYRIDINES; CHEMICAL REACTIONS; Chemistry; DATA; ELECTRON TRANSFER; ENERGY LEVELS; Exact sciences and technology; EXCITED STATES; EXPERIMENTAL DATA; General and physical chemistry; HETEROCYCLIC COMPOUNDS; INFORMATION; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; MEASURING METHODS; NUMERICAL DATA; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; PHOTOCHEMICAL REACTIONS; Physical chemistry of induced reactions (with radiations, particles and ultrasonics); PYRIDINES; SPECTROSCOPY; Intramolecular reaction; Rhenium Carbonyl Complexes; Organic ligand; Electron transfer; Photochemical reaction; Rigid chain; Donor acceptor interaction
• ISSN: 0022-3654; 1541-5740
• DOI: 10.1021/j100388a001

Two compounds (b)ReCH-DTF, which contain the metal complex chromophore (b)Re{sup I}(CO){sub 3} (where b = 2,2{prime}-bipyrazine or 5,5{prime}-bis(N,N-diethylcarbamido)-2,2{prime}-bipyridine) covalently linked to a 1,3-benzodithiafulvene (DTF) electron donor via a trans-1,4-cyclohexane (CH) spacer, have been prepared and studied by emission and transient absorption spectroscopy. Steady-state and time-resolved emission data indicate that the metal-to-ligand charge-transfer (MLCT) excited state of the (b)ReCH-DTF complexes is quenched compared to the model compounds (b)ReCH which contain the (b)Re{sup I}(CO){sub 3} chromophore but not the DTF donor. The MLCT quenching is ascribed to a rapid intramolecular DTF {yields} Re electron transfer (ET) which competes with normal radiative and nonradiative MLCT decay. The occurrence of intramolecular ET is confirmed by nanosecond transient absorption studies which reveal that the charge-transfer state, (b{sup {sm bullet}{minus}})Re{sup I}(CO){sub 3}-CH-DTF{sup {sm bullet}+}, is formed rapidly following photoexcitation.