Rhenium complex electronic properties

The ability of polypyridyl ligands to accept electron density from electron-rich rhenium centers and, thus, to contribute to the stabilization of rhenium complexes with the metal in low oxidation states has already been discussed for rhenium(II) compounds. Only small modifications to the polypyridyl ligand or the metal center can create dramatic differences in the properties of the resulting complexes. Generally, the starting materials which have been introduced as precursors for rhenium(II) polypyridyl complexes in Section 5.3.2.6.2, are also appropriate for the synthesis of related rhenium(l) compounds. 

After Section I, the photophysical processes of the rhenium complexes are briefly siunmarized the electronic structures, the photophysical relaxation processes, and the effects of intramolecular weak interaction between ligands on the photophysical properties. 

Interestingly, the electron reservoir properties of redox active ligands are also found to be useful to impose one-electron transformation on late transition metals. Rhenium complexes are known to be powerful oxo-transfer reagents [27]. However, closed-shell... 

Tris(l,2-bis(dimethylphosphino)ethane)rhenium(I), [Re(DMPE)3]+ is a simple, symmetrical cation which contains three identical bidentate phosphine ligands. This complex provides a Re(II/I) redox couple with properties that are very convenient for the study of outer-sphere electron transfer reactions.1 Specifically, this couple is stable in both alkaline and acidic media and it exhibits a reversible, one-equivalent redox potential in an accessible region [ °,(II/I) = 565 mV vs. NHE]. Moreover, this complex has been used to obtain information about the biological mechanism of action of 186Re and l88Re radiopharmaceuticals.2,3... 

In view of the strong photo oxidising properties of [Re(phen)(CO)3 (imidazole)]+ (14) (Re(I)VRe(O) = ca. + 1.3 V vs NHE in CH3CN), [Re(phen)(CO)3 (H20)]+ has been reacted with azurin to give [Re(phen)(CO)3(His83)]+-AzCu+, which has been used to study photoinduced electron-transfer reactions [47]. In the absence of quenchers, excitation of the rhenium(I) complex... 

A fairly detailed study has been made of the 1H NMR, far IR and electronic absorption spectral properties of the complexes ReNX2(PEt2Ph)3 (X = Cl, Br or I).325 The characteristic r(Re=N) modes occur close to 1000 cm-1 in the IR spectra of these and other nitrido-rhenium(V) complexes.399,404... 

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