221147-10-0Relevant academic research and scientific papers
A new electron-transfer donor for photoinduced electron transfer in polypyridyl molecular assemblies
Partigianoni, Colleen M.,Chodorowski-Kimmes, Sandrine,Treadway, Joseph A.,Striplin, Durwin,Trammell, Scott A.,Meyer, Thomas J.
, p. 1193 - 1198 (1999)
A synthetic procedure has been devised for the preparation of the reductive quencher ligand 4-methyl-4′-(N-methyl-p-tolylaminomethyl)-2,2′-bipyridine (dmb-tol), which contains toluidine covalently bound to 2,2′-bipyridine. When bound to ReI in [ReI(dmb-tol)(CO)3Cl], laser flash ReI → dmb metal-to-ligand charge-transfer (MLCT) excitation at 355 nm in CH3CN at 298 ± 2 K is followed by efficient, rapid (a transient with an absorption feature at 470 nm. The transient spectrum is consistent with formation of the redox-separated state, [ReI(dmb--tol+)(CO)3Cl], which returns to the ground state by back electron transfer with kET = (1.05 ± 0.01) × 107 s-1 (τ = 95 ± 1 ns) at 298 ± 2 K. Rapid, efficient quenching is also observed in the RuII complex [Ru(4,4′-(C(O)NEt2)2bpy)2(dmb-tol)] 2+. Based on transient absorption measurements, a rapid equilibrium appears to exist between the initial metal-to-ligand charge-transfer excited state and the redox-separated state, which lies at higher energy. Decay to the ground state is dominated by back electron transfer within the redox-separated state which occurs with k > 4 × 108 s-1 at 298 ± 2 K.
