The Coordination and Bioinorganic Chemistry of Molybdenum
09 Mar 2007-pp 1-223
About: The article was published on 2007-03-09. It has received 78 citations till now. The article focuses on the topics: Bioorganometallic chemistry & Bioinorganic chemistry.
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TL;DR: The 2011 WHO Guidelines for Drinking-Water Quality (fourth edition) advised a health-based value of 70μg/L for Mo but this is no longer promulgated as a formal guideline value as WHO consider such concentrations to be rarely found in drinking water as discussed by the authors.
196 citations
TL;DR: An overview of the current state of our understanding of the molybdenum-containing enzyme xanthine oxidoreductase is presented, with an emphasis on work done in the past five years.
Abstract: An overview of the current state of our understanding of the reaction mechanism of the molybdenum-containing enzyme xanthine oxidoreductase is presented, with an emphasis on work done in the past five years Recent studies of the biosynthesis of the pterin cofactor bound to the metal in the active site are also reviewed, as is crystallographic work that has clarified the coordination geometry of the molybdenum center This structural work provides the context in which to understand recent mechanistic studies of the enzyme, in particular those aimed at elucidating the role of specific amino acid residues in the active site of the enzyme(© Wiley-VCH Verlag GmbH & Co KGaA, 69451 Weinheim, Germany, 2006)
119 citations
TL;DR: In this article, synthetic aspects of molybdenum sulfide-based materials were reviewed, with emphasis on the catalytic materials, and a number of preparation methods were critically compared, including molecular precursor decomposition, hydrothermal, soft chemistry aqueous, surfactant-aided, intercalation-exfoliation, and solid gas reactions.
114 citations
TL;DR: The ability of Desulfovibrio desulfuricans formate dehydrogenase (DdFDH) to reduce carbon dioxide was kinetically and mechanistically characterized and a kinetic model of a hysteretic enzyme is proposed to interpret and predict the progress curves of the Dd FDH-catalyzed reactions.
Abstract: Carbon dioxide accumulation is a major concern for the ecosystems, but its abundance and low cost make it an interesting source for the production of chemical feedstocks and fuels. However, the thermodynamic and kinetic stability of the carbon dioxide molecule makes its activation a challenging task. Studying the chemistry used by nature to functionalize carbon dioxide should be helpful for the development of new efficient (bio)catalysts for atmospheric carbon dioxide utilization. In this work, the ability of Desulfovibrio desulfuricans formate dehydrogenase (Dd FDH) to reduce carbon dioxide was kinetically and mechanistically characterized. The Dd FDH is suggested to be purified in an inactive form that has to be activated through a reduction-dependent mechanism. A kinetic model of a hysteretic enzyme is proposed to interpret and predict the progress curves of the Dd FDH-catalyzed reactions (initial lag phase and subsequent faster phase). Once activated, Dd FDH is able to efficiently catalyze, not only t...
103 citations
TL;DR: The mesoporous molecular sieve MCM-41 was covalently grafted with 3-aminopropyl trimethoxysilane (AmpMCM41) in this article.
Abstract: The mesoporous molecular sieve MCM-41 was covalently grafted with 3-aminopropyl trimethoxysilane to give aminopropyl modified MCM-41 (AmpMCM-41). Reaction of this material with furfural, pyrrolcarbaldehyde, 2-acetylpyrrol, 2-aminoacetophenone, salicylaldehyde and acetylacetone afforded the corresponding supported Schiff base ligands. Subsequent reaction with bis(acetylacetonato)dioxomolybdenum(VI) leads to various molybdenum complexes supported on MCM-41 through propyl chain spacer. Characterization of these materials was carried out with FT-IR, atomic absorption spectroscopy, powder X-ray diffraction (XRD) and BET nitrogen adsorption–desorption methods. The XRD and BET analyses revealed that textural properties of support were preserved during the grafting experiments. The resultant materials successfully catalyzed the epoxidation of cyclooctene, cyclohexene, 1-hexene and 1-octene with tert -butyl hydroperoxide (TBHP) to the corresponding epoxides with 98–100% selectivities.
92 citations
References
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TL;DR: In this paper, a molecular orbital formulation is given for the spin Hamiltonian parameters, and terms dependent on spin-orbit interactions near ligand nuclei are found, applied to the experimental results by means of an empirical method including radial expansion effects, and estimates of certain LACO-MO coefficients are obtained.
Abstract: Electron spin resonance data for [VOCl5]3— and [MoOCl5]2— in dilute single crystals are reported and and analyzed to give the spin Hamiltonian parameters for these complexes. A molecular orbital formulation is given for the spin Hamiltonian parameters, and terms dependent on spin—orbit interactions near ligand nuclei are found. This formulation is applied to the experimental results by means of an empirical method including radial expansion effects, and estimates of certain LACO—MO coefficients are obtained. The bonding in [VOCl5]3—, [VO(H2O)5]2+, and [MlOCl5]2— is discussed in terms of these LCAO—MO coefficients.
110 citations
109 citations
108 citations
TL;DR: In this paper, the bounds for the rounding errors made in the fundamental floating-point arithmetic operations are derived for a number of computing techniques for the calculation of the eigenvalues of matrices, in each case the computed solution is expressed as the exact solution of a perturbed version of the original matrix.
Abstract: This paper consists of two main sections. In the first the bounds are derived for the rounding errors made in the fundamental floating-point arithmetic operations. In the second, these results are applied in the analysis of a number of computing techniques for the calculation of the eigenvalues of matrices. In each case thecomputed solution is expressed as the exact solution of a perturbed version of the original matrix and bounds are found for the perturbations. For one of the techniques, an a priori bound is derived for the errors in the eigenvalues themselves.
107 citations
TL;DR: It is shown that a simple molecular mechanism embodying coupled proton-electron transfer can explain many key experimental observations and the reasons for the use of Mo are discussed and other metals that may replace Mo are considered.
Abstract: The reactions catalyzed by Mo enzymes each find the product differing from the substrate by two electrons and two protons (or some multiple thereof). The coordination chemistry of Mo suggests that there is a distinct relationship between acid-base and redox properties of Mo complexes, and that a coupled electron-proton transfer (to or from substrate) may be mediated by Mo in enzymes. Each of the Mo enzymes (nitrogenase, nitrate reductase, xanthine oxidase, aldehyde oxidase, and sulfite oxidase) is discussed; it is shown that a simple molecular mechanism embodying coupled proton-electron transfer can explain many key experimental observations. In view of this mechanism, the reasons for the use of Mo (from an evolutionary and chemical point of view) are discussed and other metals that may replace Mo are considered.
106 citations