Energy transfer ruthenium polypyridine complexes

Figure 9 Plot of nk as a function of free energy for electron-transfer reactions of Ru-65-c)d 65 labeled with different ruthenium polypyridine complexes. The solid tine shows the theoretical dependence of equation (1) calculated with a reorganizational energy of 0.94 eV and a distance r of 13 A. The open boxes are for the reactions involving the excited state, = ki, and the filed boxes are for the thermal back reactions, ki-i = k2, all determined at 22 °C. (Reprinted with permission from Ref. 55. 1993 American Chemical Society)...

Balzani et al. prepared dendrimers with metal complexes serving both as core [36] and as branching unit The metallodendrimer in Fig. 2.10 is constructed solely from polypyridine ligands and transition metal ions. Such dendritic transition metal complexes can be synthesised both convergently and divergently and different transition metal ions (ruthenium/osmium) can be incorporated. This provides a means of influencing the luminescence properties of the den-drimer. Thus the energy transfer process proceeds from the inside outwards in... 

Scott JR, Fairris JL, McLean M, et al. Intramolecular electron-transfer reactions of cytochrome 5 covalently bonded to ruthenium(II) polypyridine complexes reorgani-zational energy and pressure effects. Inorg Chim Acta 1996 243 193-200. 

In related model complex studies, Isied and coworkers, have examined photo-induced (or pulse-radiolytically initiated) electron-transfer processes in which a polypyridine-ruthenium(II) complex is linked by means of a 4-carboxylato,4 -methyl,2,2 -bipyridine ligand and a polyproline chain to a [Co(NH3)5] + or [(-NH-py)Ru (NH3)5] acceptor. Chains composed of from zero to six cis-prolines have been examined. The apparent distance dependence of the electron-transfer rate constant, corrected for variations in the solvent reorganizational energy, seems to exhibit two types of distance dependence, 0.7-1A for short chains and /3 a0.3 A for long chains. A very detailed theoretical analysis of electron transfer in the complexes with four proline linkers has indicated that the electronic coupling is sensitive to conformational variations within the proline chain. ... 

Free-Energy Dependence of Electron Transfer in Cytochrome c Labeled with Ruthenium(II)-Polypyridine Complexes... 

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