Chelating ligands chromium

Chromium, (ri6-benzene)tricarbonyl-stereochemistry nomenclature, 1,131 Chromium complexes, 3,699-948 acetylacetone complex formation, 2,386 exchange reactions, 2,380 amidines, 2,276 bridging ligands, 2,198 chelating ligands, 2,203 anionic oxo halides, 3,944 applications, 6,1014 azo dyes, 6,41 biological effects, 3,947 carbamic acid, 2,450 paddlewheel structure, 2, 451 carboxylic acids, 2,438 trinuclear, 2, 441 carcinogenicity, 3, 947 corroles, 2, 874 crystal structures, 3, 702 cyanides, 3, 703 1,4-diaza-1,3-butadiene, 2,209 1,3-diketones... 

Non-ionic thiourea derivatives have been used as ligands for metal complexes [63,64] as well as anionic thioureas and, in both cases, coordination in metal clusters has also been described [65,66]. Examples of mononuclear complexes of simple alkyl- or aryl-substituted thiourea monoanions, containing N,S-chelating ligands (Scheme 11), have been reported for rhodium(III) [67,68], iridium and many other transition metals, such as chromium(III), technetium(III), rhenium(V), aluminium, ruthenium, osmium, platinum [69] and palladium [70]. Many complexes with N,S-chelating monothioureas were prepared with two triphenylphosphines as substituents. 

Chromium complexes acetylacetone complex formation, 386 exchange reactions, 380 amidines, 276 bridging ligands, 198 chelating ligands, 203 carbamic add, 450 paddlewheel structure, 451 carboxylic adds, 438 trinuclear, 441 oorroles, 874... 

Photoreactions of [Cr(CO)3( /6-C7H8)] (41) with 6-mono- and 6,6-disub-stituted pentafulvenes (59a-59f) preferentially yield dicarbonyl complexes with substituted tj3 5-2-cyloheptadienylene-2-cyclopentadienylidenemethane chelate ligands (82,83). In the course of the reaction, C-6 of the fulvene forms a C—C bond to C-l of the 1,3,5-cycloheptatriene ligand, and one CO ligand is displaced. This reaction is of the same type as the formation of the f/3 5-[ 1 -(3-butene-1,2-diyl)-7-isopropylidenecycloheptadienyl] complexes 47c, 47e and 47t. The fulvene unit is transformed into a monosubstituted cyclo-pentadienyl entity, / -coordinated to the chromium, with the 1,3,5-cyclo-... 

Differences in the intracellular metabolic pathways that result in the reduction of chromium(VI) will affect the nature of the reactive intermediates. For example, chelating ligands, such as glutathione and... 

Some of the chelating ligands used to form chromium clusters are shown in Fig. 8. 

A molecule is optically active when it cannot be superimposed on its mirror image. Although this condition is met by an octahedral complex such as MLaLbLgLdLgLf it is rare indeed to be able to resolve such a complex. In practice, optical activity is largely confined to octahedral complexes of chelating ligands. Optical activity has also been observed for chelated tetrahedral and square planar complexes but only rarely. It is necessary for the chelated complex to be stable kinetically to permit resolution, it must retain its configuration for at least a matter of minutes. This confines attention to complexes of a few ions, of which cobalt(III), chromium(III)... 

Elschenbroich C, Hurley J, Metz B (1990) Metal.ic.-complexes of benzene derivatives. 34. Tetraphenylsilane as a chelating ligand synthesis, stmctural characterization, and reactivity of the tilted bis(arene) metal complexes [(C6H5)2Si(.eta.6- C6H5)2]M (M - vanadium, chromium). OrganometaUics 9 889-897... 

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