Ligands polypyridyl

Asymmetric ECH with [Rh(L)2(Cl)2]+ complexes containing chiral polypyridyl ligands has been attempted, in homogeneous media (L = (7)-(12)) and at carbon electrodes coated with polymer films prepared by electropolymerization of [Rh(13)2(Cl)2]+ -61 62 The latter catalytic system gave the best results in terms of turnover number (up to 4,750) and enantiomeric excess, (ee) when applied to the hydrogenation of acetophenone (ee 18%) and 2-butanone (ee 10%).62 Polymeric materials derived from the complexes [RhI(bpy)(COD)]+ 36 and [Pd(bpy)2]2+33have also been applied to the ECH reaction. 

Numerous metal complexes have been proven to be active electrocatalysts for C02 reduction.1,66-68 These catalysts can be conveniently grouped into three main families metal complexes with polypyridyl ligands, metal complexes with macrocyclic ligands, and metal complexes with phosphorus ligands. 

Polypyridyl ligands are able to stabilize electron-rich metal centers as has been shown for the d -systems Ru and Os. This suggests this class of ligands also to be appropriate for rhenium(I) compounds, and this will be discussed more in detail in Section 5.3.2.7.2, and rhenium(II) complexes which represent intermediates in the syntheses of the Re species or are accessed by oxidation of Re. ... 

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. 

Designing potential DNA intercalators has led to an investigation of a series of [Ru([9]aneS3)LCl] complexes where L is a didentate polypyridyl ligand. Structural data for the complexes are discussed in terms of hydrogen-bonded interactions and rr-stacking between extended aromatic systems, e.g., dppz and 4,7-Ph2phen. " ... 

Dioxoruthenium(V) and dioxoosmium(V) species containing polypyridyl ligands, cis- and trans-... 

As shown by their redox potentials oxoruthenium(IV) species containing polypyridyl ligands are strong oxidants and they oxidize a variety of substrates. The complex [Ru(0)(bpy)2(py)] has also been used electrocatalytically for the oxidation of alcohols, aldehydes, alkenes, and aromatics." Electrocatalytic oxidation has also been performed on this complex that has been incorporated into poly-4-vinylpyridine. ... 

Although the polypyridyl ligands are reported to be quite stable after coordination, covalent hydration and pseudo-base formation have been reported, although not proved unequivocally.134... 

Oxo-bridged ruthenium(VMV) dimers of polypyridyl ligands have been suggested as intermediates for the oxidation of H20 to 02 in a concerted four-electron step (62, 63) ... 

Sauaia MG, de Souza Oliveira F,Tedesco AC, Santana a Silva R. Control of NO release by light irradiation from nitrosyl-ruthenium complexes containing polypyridyl ligands. Inorg Chim Acta 2003 355 191-6. 

Pt11 Acetylides with Bidentate Polypyridyl Ligands. 161... 

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