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Book ChapterDOI

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.
Citations
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Journal ArticleDOI
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

Journal ArticleDOI
Russ Hille1
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

Journal ArticleDOI
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

Journal ArticleDOI
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

Journal ArticleDOI
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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Journal ArticleDOI
TL;DR: It is now possible to devote an entire review to the biochemistry of symbiotic nitrogen fixation, although most of the information has come from the study of only four legu mes-soybeans, lupines, serradella.
Abstract: to be solved. For example, the role of each of the two components of the complex is not known and the high requirement for energy from ATP is not understood. Most recent reviews, including those from authors other than the above (37, 62, 66, 106), have included references to symbiotic systems. It is now possible to devote an entire review to the biochemistry of symbiotic nitrogen fixation, although most of the information has come from the study of only four legu mes-soybeans, lupines, serradella,

156 citations

Journal ArticleDOI
TL;DR: The difference spectrum of oxidized native sulfite oxidase minus inactive protein revealed subtle differences in the environments of the heme prosthetic group, hydrophobic aromatic residues, and possibly sulfhydrylmolybdenum linkages.

152 citations

Journal ArticleDOI
TL;DR: The results indicate that the role of the azoferredoxin · ATP complex may not be confined solely to the function of an electron carrier for the nitrogenase reaction.
Abstract: The oxidation-reduction properties of azoferredoxin, molybdoferredoxin, and the inactive species of molybdoferredoxin, all iron-sulfur proteins purified from Clostridium pasteurianum, were studied by potentiometry combined with electron paramagnetic resonance spectroscopy at low temperature. The technique, evaluated with spinach ferredoxin for which a midpoint potential of -446 mV was determined (pH 7.9, showed that azoferredoxin has a midpoint potential of -294 ± 20 mV (pH 7.5). In the presence of MgATP2−, azoferredoxin undergoes a negative shift of 110 mV in its oxidation-reduction potential. The resulting potential of approximately -400 mV is likely to be effective under physiological conditions. The potential shift is consistent with a proposed conformational change of the protein caused by the binding of two molecules of ATP to the protein (dimer). Molybdoferredoxin and its inactive species, which has an incomplete iron-sulfur and molybdenum centre, have midpoint potentials of approximately −20 mV and −395 mV, respectively, both at pH 7.5. All nitrogenase proteins are characterized by the transfer of one electron per redox step. Kinetic studies of the reduction of azoferredoxin and molybdoferredoxin by dithionite gave half times of <10 ms and 3–5 min, respectively. Hence, the latter process must be excluded from being part of the physiological reaction. The complex formation of ATP with azoferredoxin is a relatively slow process, which is markedly accelerated by molybdoferredoxin in the reconstituted nitrogenase system. Changes in the electron paramagnetic resonance signals of reconstituted nitrogenase were followed by a rapid-freeze technique as a function of mixing sequence and ratio of the two proteins. The observed signal changes were independent of the mixing sequence. The steady-state level of the molybdoferredoxin signal was also independent of the ratio of the two proteins and was less than 15% of the original resonance. The results indicate that the role of the azoferredoxin · ATP complex may not be confined solely to the function of an electron carrier for the nitrogenase reaction.

151 citations