Syntheses of sulphur-bridged molybdenum and tungsten coordination compounds

Electrochemistry and redox behaviour of transition metal dithiocarbamates

Publisher Summary This chapter presents a discussion on the bioinorganic chemistry of pterin-containing molybdenum and tungsten enzymes. The chapter focuses on the current results and the interplay of model and enzyme chemistry. Attention is directed to sulfite oxidase and xanthine oxidase, the archetypal examples of molybdenum enzymes, containing, respectively, dioxo-Mo(VI) and oxo-thio-Mo(VI) oxidized centers. Biochemical and model studies of molybdopterin, Mo-co, and related species are described in this chapter. A brief survey on the physical and spectroscopic techniques employed in the study of the enzymes is presented and their impact on the current understanding of the coordination about the molybdenum atom in sulfite oxidase and xanthine oxidase is discussed. Structural and spectroscopic models are also presented in the chapter. The chapter also explains the xanthine oxidase cycle and facets of intramolecular electron transfer in molybdenum enzymes. The pterin-containing tungsten enzymes and the evolving model chemistry are discussed. Current descriptions of the coordination environment of the molybdenum centers of the enzymes rest primarily upon the comparisons of the spectra of the enzymes with the spectra of well-characterized molybdenum complexes. The unexpected discovery that several hyperthermophilic organisms possess pterin-containing tungsten enzymes promises to stimulate the development of oxo-thio-tungsten chemistry.

Bioinorganic chemistry of pterin-containing molybdenum and tungsten enzymes

Oil-soluble MO-S compounds as lubricant additives

Publisher Summary This chapter discusses the organometallic compounds containing oxygen atoms. At present, the range of organic ligands found in organometallic oxo compounds is quite restricted, the majority being either η-C 5 R 5 or alkyls or aryls having no β-hydrogen atom. Two basic routes to organometallic oxo compounds may be envisaged addition of an organic ligand to an inorganic oxo complex or addition of oxygen to an organometallic compound. Exhaustive decarbonylation with concomitant oxidation of a cyclopentadienyl metal carbonyl has proved to be a useful preparative route to cyclopentadienyl metal oxo compounds having no other ligands. In the ethylene complex, the oxo and ethylene ligands are cis to one another and the C–C axis of the ethylene is perpendicular to the M–O bond, a configuration that maximizes π bonding between the W(IV) (d 2 ) and the ethylene. Complexes containing cyclopentadienyl and oxygen as coligands are of two basic types: those containing a terminal double bond between a metal and oxygen, [M=O], and those containing one or more doubly bridging oxygen atoms, [M(μ 2 -O) n M]. The clusters are held together by M–O bonds and the M–( η 5 -C 5 H 5 ) bonding is of the usual type. Parallel to the development of organometallic clusters containing oxygen atoms has been the preparation of organometallic polyoxometallates. Although the organometallic groups are on the surface of the polyoxometallate, they are strongly and covalently bonded to the peripheral oxygen atoms.

Organometallic Compounds Containing Oxygen Atoms

Preparation and characterization of two series of dimeric molybdenum(V) N,N-dialkyldithiocarbamates. Their interrelation and chemistry as a model for the active site of nitrogenase

Dudley C. Bravard

Papers

Preparation and characterization of two series of dimeric molybdenum(V) N,N-dialkyldithiocarbamates. Their interrelation and chemistry as a model for the active site of nitrogenase

Synthesis and electrochemistry of oxo- and sulfido-bridged molybdenum(V) complexes with 1,1-dithiolate ligands

Reactions of oxobis(N,N-dialkyldithiocarbamato) molybdenum(IV) with unsaturated organic molecules and their biochemical implications

Rk. von oxo-bis-(n,n-dialkyldithiocarbamato)-molybdaen(iv) mit ungesaettigten organischen molekuelen und ihre biochemischen folgerungen