Oxides bridging ligands

While bridging carbonyl and hydrido ligands are often present in metal metal bonded dimers, halogens are probably the most common bridging ligands. Oxidation by halogens under controlled conditions leads to the Mo -bridged dimers as shown in equation (13). 

We postulate that binding to the surface can be either direct, via metal-metal bond, or indirect through a bridging ligand oxide ion or possibly a bridging chloride or hydrogen atom. In general several of these surface compounds will coexist and, in favourable circumstances, these can now be identified and quantified by TPR. ... 

H2 or O2 from water in the presence of a sacrificial reductant or oxidant employ a mthenium complex, typically [Ru(bipy)2], as the photon absorber (96,97). A series of mixed binuclear mthenium complexes having a variety of bridging ligands have been the subject of numerous studies into the nature of bimolecular electron-transfer reactions and have been extensively reviewed (99—102). The first example of this system, reported in 1969 (103), is the Creutz-Taube complex [35599-57-6] [Ru2(pyz)(NH3. 

Ardon M, Bino A (1987) A New Aspect of Hydrolysis of Metal Ions The Hydrogen-Oxide Bridging Ligand (H3O-2). 65 1-28 Arendsen AF, see Hagen WR (1998) 90 161-192... 

CNs, the Fe ion is postulated to be coordinated by one SO and a mixture of CO and CNs. The interpretation is based on the temperature factor refinement and pyrolytic analysis of oxidized sulfur species (33). In addition, the bridging ligand is postulated to be an inorganic sulfur ion (instead of an oxo ligand, as proposed for the D. gigas). This... 

A related dinuclear species 77, recently described, constitutes the first dinuclear gold(I) complex with heterobridged phosphor-1,1 -dithiolato moieties and bis(ylide) bridging ligands [ 102]. It is obtained by reaction between [ AuS2PPh2] and the diylide gold complex 74 (R=Me). No intermolecular Au-Au interaction is observed in 77 but the oxidative addition of chlorine to the product leads to a new complex 78 in which a single bond is formed between the two Au(II) centers (Scheme 26). 

The binuclear Ir complex (93) is produced from the direct coupling reaction of the Ir-bound 5-chloro-phen ligand as shown in reaction Scheme 12.153 The nonplanar structure of the bridging ligand results in the electronic isolation of the two Ir centers. Hence both metal centers and ligands are oxidized and reduced, respectively, in two-electron processes. 

Lippert and co-workers have reported a similar series of A-,O-bridged platinum(III) dimers in which the bridging ligands are the pyrimidines, 1-methyluracil, 1-methylthymine, or 1-ethylthy-mine. Chemical oxidation of dimeric platinum(II) complexes gave [Pt2XY(L)2(NH3)4]2+, X,Y = N03", N02, H20, Cl", or Br", L=l-MeU, 1-MeT, 1-EtT. 27 t30 They too found that the HT dimers are more stable than the HH.430... 

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