Coordination chemistry alcohols

Copper(II) complexes with phenoxo ligands have attracted great interest, in order to develop basic coordination chemistry for their possible use as models for tyrosinase activity (dimeric complexes) and fungal enzyme galactose oxidase (GO) (monomeric complexes). The latter enzyme catalyzes the two-electron oxidation of primary alcohols with dioxygen to yield aldehyde and... 

Huhert-Pfalzgraf LG (1998) Some aspects of home and heterometallic alkoxides based on fimctional alcohols. Coordination Chemistry Reviews 180, 967-997 Huhert-Pfalzgraf LG (2003) Some trends in the design of homo- and heterometallic molecular precimsors of high-tech oxides. Inorganic Chemistry Communications 6(1), 102-120... 

A variety of chelate complexes of Al3+ with N and/or O donor atoms are known through stability constant data.7,8 Their formation illustrates several aspects of A1 coordination chemistry. Chelates and other multidentate ligand systems provide a means of regulating the reactivity of aluminum compounds. For example, A1 alkoxides can be converted to amino alcohol derivatives to confer water solubility and a degree of hydrolytic stability on otherwise water-sensitive materials. 

We shall now briefly outline some of the features of the zinc metalloenzymes which have attracted most research effort several reviews are available, these are indicated under the particular enzyme, and for more detailed information the reader is referred to these. Attention is focussed here, albeit briefly, on carbonic anhydrases,1241,1262,1268 carboxypeptidases, leucine amino peptidase,1241,1262 alkaline phosphatases and the RNA and DNA polymerases.1241,1262,1462 Finally, we examine alcohol dehydrogenases in rather more detail to illustrate the use of the many elegant techniques now available. These enzymes have also attracted much effort from modellers of the enzymic reaction and such studies, which reveal much interesting coordination chemistry and often new catalytic properties in their own right—and often little about the enzyme system itself (except to indicate possibilities), will be mentioned in the next section of this chapter. 

The action of transition metals in the carbonylations of alcohols is treated by Dekleva and Forster. This is a field of important chemistry, from the point of view of coordination chemistry as well as catalysis. It is also another example of cross-stimulation between basic science and technological utility. 

In the evolution of anion coordination chemistry, it was discovered that neutral molecules can also operate as effective receptors for anions provided that they contain polarised N-H fragments (e.g. of amides [53], ureas [54], thioureas [55] or pyrroles [56]), which act as H-bond donors for anions. These receptors cannot compete for hydrogen bonding with water and alcohols and must be studied in aprotic solvents of varying polarity, e.g. CHCI3, MeCN, DMSO. In this vein,... 

Alkoxide and aryloxide ligands are excellent ligands for the actinides. As a result, these ligands have been studied extensively in the coordination chemistry and reactivity of tri-, tetra-, penta-, and hexavalent actinides. The alkoxides and aryloxides can be synthesized by a variety of routes the two most popular routes include direct reaction of actinide halides with alkali metal salts of the alkoxide or aryloxide of interest and protonolysis of actinide amides by alcohols. 

Although the above examples have been classified in terms of donor sets, an alternative approach is to report mixed donor ligands in terms of their family relationship as amino alcohols or hydroxyacids, for example or in terms of the type of complexes they form - as polynuclear systems, for example. Although these have been addressed above in another context, it is appropriate to recognize a few ligand families that are of particular importance (historically, numerically, or in applications) in coordination chemistry. The selection is not designed to be exhaustive, but merely indicative of mixed donor ligand families. 

A widely used precursor for Rh(I) and Ir(I) in coordination chemistry is the [MC1(C0D)]2 dimer (120). In the presence of either free NHC or in situ generated carbene from the alcohol adduct or the combination imidazolium salt and base, the dimer was cleaved giving rise to [(NHC)MCl(COD)] (121) (Scheme 20). The presence of labile COD allowed for further modification of the metal coordination sphere. For example, under CO atmosphere the COD ligand was rapidly removed, leaving two CO binding the metal center. The... 

In order to elucidate the coordination chemistry of individual carbohydrates, the following review will be carbohydrate-oriented instead of metal-oriented, that is, the stmctures of individual carbohydrates or, if only few structures are known, of a group of related carbohydrates are discussed en-block. We will start with complexes of simpler carbohydrates such as sugar alcohols or anhydroerythritol in order to derive the basics of metal coordination and will then proceed to typical carbohydrates. 

In the hypervalent area of phosphorus chemistry a configurationally stable tris(tetrachlorobenzenediolato) phosphate ion has been synthesised. The growing importance of hydridophosphoranes in coordination chemistry has led to the apprearance of a useful review. The superbase properties of the commercially available proazaphosphatrane has been extended to the catalysis of the silylation of sterically hindered alcohols and phenols. 

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