Catecholate ligand

These complexes combine a central metal in a high oxidation state with a redox active ligand (catechol). This combination arises from the idea that the electronic perturbation induced in the metal complex by reaction with dioxygen can discharge itself ... 

Several metals, including iron, copper and tin, can fog emulsions. Emulsions can be partly stabilized by sequestering these metallic species with suitable ligands. Catechol derivatives are reported to be helpful in preventing fog from this source. Examples include 1,2-dihydroxy-benzene-4-sulfonic acid (sodium salt) and l,2-dihydroxybenzene-3,5-disulfonic acid (disodium salt).37... 

The non-innocent ligand catechol forms very stable osmium(VI) complexes, as do a number of substituted catechols. 

In this series the aromatic ligands catechol and tropolone afford chelates whose chemical shift is a function of the number of oxygen atoms around silicon and the nature of the non-chelating group attached to silicon. Thus the cationic and anionic hexacoordinate complexes [41], [51], and [52] have essentially the same chemical shifts whether tropolone or catechol is the ligand. 

X.-C. Liu, J. L. Hubbard, W. H. Scouten, Synthesis and structural investigation of two potential boronate affinity chromatography ligands catechol [2-(diisopropylamino)carbonyl]phenylboronate and catechol [2-(diethylamino) carbonyl, 4-methyl]phenylboronate, Journal of Organometallic Chemistry 1995, 493,91. 

To reduce the binding pH, Scouten and co-workers first synthesized a novel boronate affinity ligand, catechol [2-(diethylamino)carbonyl-4-bromomethyljphenylboronate, which contains intramolecular B-O coordination. Then, this ligand was coupled to sulfhydryl cellulose. The novel boronate affinity gel bound the glycoprotein horseradish peroxidase (HRP) at neutral condition (pH 7.0), at which the immobilized enzyme retain 90.12% of its original activity. 

Transition metal complexes of o-benzoquinone, o-semiquinone and catecholate ligands. C. G. Pier-pontand R. M. Buchanan, Coord. Chem. Rev., 1981, 38, 45-87 (72). 

The development of catalysts for the efficient oxidation of catechol and its derivatives in water is topic of ongoing work in this laboratory. Towards this end, polyethylene glycol side-chains were incorporated in a pentadentate salen ligand to enhance the water solubility of the complexes derived thereof. A dinuclear copper(II) complex is found to catalyze the oxidation of 3,5-di-tert.-butylcatechol into 3,5-di-tert-butyl-o-benzoquinone more than twice as fast in aqueous organic solution as in purely organic solvents (ly,at/knon= 140,000). Preliminary data are discussed. 

Complexes with deprotonated hydroxamic acids, catechols, and related ligands 319... 

A variety of ternary complexes containing catecholate moieties are known. For example, in a trimeric Ni11 core the catecholate serves as a bidentate ligand to one Ni11 and also as a bridge between the two podal and the unique axial metal.766... 

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