The binuclear complex RuII(Me2phen)2-(Mebpy-CH2-CH2-Mebpy)-RhIII(Me2bpy)25+ (Me2phen = 4, 7-dimethyl-l, 10-phenanthroline; Mebpy = 4-methyl-2, 2′-bipyridine; Me2bpy = 4, 4′-dimethyl-2, 2′-bipyridine), hereafter represented by Ru(II)-Rh(III), was synthesized and studied. Selective excitation of the two moieties of the dyad was achieved with visible (100% *Ru(II)-Rh(III)) or ultraviolet light (e.g., at 298 nm, 70% Ru(II)-*Rh(III)). In room-temperature fluid solutions, both local excited states are quenched by electron transfer, leading to a common Ru-(III)-Rh(II) state. The two forward electron-transfer processes, as well as the recombination process leading back to the ground state, can be resolved by transient laser spectroscopy, using various excitation wavelengths and pulse widths (532 nm, 30 ps; 427 nm, 0.5 ps; 298 nm, 0.5 ps). Rate constants in acetonitrile are as follows: *Ru(II)-Rh(III) → Ru(III)-Rh(II), 1.7 X 108s-1; Ru(II)-*Rh(III) → Ru(III)-Rh(II), 3.3 X 1010 s-1; Ru(III)-Rh(I...
Four Intercomponent Processes in a Ru(II)-Rh(III) Polypyridine Dyad: Electron Transfer from Excited Donor, Electron Transfer to Excited Acceptor, Charge Recombination, and Electronic Energy Transfer
INDELLI, Maria Teresa;BIGNOZZI, Carlo Alberto;SCANDOLA, Franco
1994
Abstract
The binuclear complex RuII(Me2phen)2-(Mebpy-CH2-CH2-Mebpy)-RhIII(Me2bpy)25+ (Me2phen = 4, 7-dimethyl-l, 10-phenanthroline; Mebpy = 4-methyl-2, 2′-bipyridine; Me2bpy = 4, 4′-dimethyl-2, 2′-bipyridine), hereafter represented by Ru(II)-Rh(III), was synthesized and studied. Selective excitation of the two moieties of the dyad was achieved with visible (100% *Ru(II)-Rh(III)) or ultraviolet light (e.g., at 298 nm, 70% Ru(II)-*Rh(III)). In room-temperature fluid solutions, both local excited states are quenched by electron transfer, leading to a common Ru-(III)-Rh(II) state. The two forward electron-transfer processes, as well as the recombination process leading back to the ground state, can be resolved by transient laser spectroscopy, using various excitation wavelengths and pulse widths (532 nm, 30 ps; 427 nm, 0.5 ps; 298 nm, 0.5 ps). Rate constants in acetonitrile are as follows: *Ru(II)-Rh(III) → Ru(III)-Rh(II), 1.7 X 108s-1; Ru(II)-*Rh(III) → Ru(III)-Rh(II), 3.3 X 1010 s-1; Ru(III)-Rh(I...I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
