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: These results are discussed in terms of a role for ATP in nitrogen fixation in crude preparations of nitrogenase, which were normally oxygen-tolerant but became oxygen-sensitive in the presence of either ATP, GTP, ITP, UTP, CTP or sodium pyrophosphate.
Abstract: 1Crude preparations of nitrogenase (AS1) from Azotobacter chroococcum which were normally oxygen-tolerant, became oxygen-sensitive in the presence of either ATP, GTP, ITP, UTP, CTP or sodium pyrophosphate. MgCl2 antagonised this effect of ATP.
2ATP-induced oxygen damage was faster at 4°C than at 30°C.
3ATP-induced oxygen damage to prepn AS1 affected fraction 2 (Ac2) of the nitrogenase; fraction 1 (Ac1) was unaffected. Purified fraction Ac2 became hypersensitive to oxygen in the presence of ATP.
4Pre-treatment of prepn AS1 with “Chelex 100” or EDTA under anaerobic conditions made the nitrogenase oxygen-sensitive. Oxygen-tolerance was partly restored by metal ions. Similar anaerobic pre-treatment of prepn AS1 with ATP followed by removing the ATP by dialysis did not induce oxygen-sensitivity.
5Pure fraction Ac2 bound significantly more [14C]ATP in the presence of MgCl2 than did EDTA-treated fraction Ac2 in the absence of MgCl2.
6Hill plots of the ATP requirement for acetylene reduction, for ATP-induced oxygen damage, for the MgCl2, requirement for acetylene reduction and for the MgCl2, requirement for protection against oxygen damage to EDTA-treated prepn AS1 all yielded nvalues between 1 and 2.
7These results are discussed in terms of a role for ATP in nitrogen fixation.
27 citations
TL;DR: In this paper, the authors show that Kalium-Nitrosylpentacyanomolybdat wird ferner durch Umsetzungen mit Oxydationsmitteln naher charakterisiert und hierbei auch sein Stickoxydgehalt ermittelt.
Abstract: Die seit langem bekannte Reaktion zwischen Molybdat, Kaliumcyanid und Hydroxylamin fuhrt zu einem Nitroprussiat des Molybdans der Zusammensetzung K4[Mo(CN)5NO] 2 H2O, dessen Bildung sich auf die kurzlich beschriebene Disproportionierung des Hydroxylamins zuruckfuhren laβt. Die fruhere Auffassung der blauvioletten Verbindung als MoO2 4 KCN NH2OH H2O konnte besonders durch eine neue Cyanbestimmungsmethode, die gleichzeitig die neue Formulierung als Nitroprussiat bestatigt, widerlegt werden. Das Kalium-Nitrosylpentacyanomolybdat wird ferner durch Umsetzungen mit Oxydationsmitteln naher charakterisiert und hierbei auch sein Stickoxydgehalt ermittelt.
Das Molybdan befindet sich in diesem Komplex im gleichen Bindungszustand wie im Mo(CO)6 und es wird durch die Existenz dieser Verbindung grundsatzlich bewiesen, daβ auch die Ubergangsmetalle der 6. Gruppe des periodischen Systems “edelgasartige” Nitroprussiationen bilden.
Auf strukturelle Analogien und eventuelle Unterschiede gegenuber den Nitroprussiaten der 7. und 8. Gruppe des periodischen Systems wird hingewiesen.
27 citations
TL;DR: Tetrakistetramethylenedithiocarbamatometals M[S2CN(CH2)4]4(M = NbIV, MoIV, and WIV) have been prepared by reactions of ammonium tetramer methylenedithIocarbamate and the respective metal tetrachloride in acetonitrile.
Abstract: Tetrakistetramethylenedithiocarbamatometals M[S2CN(CH2)4]4(M = NbIV, MoIV, and WIV) have been prepared by reactions of ammonium tetramethylenedithiocarbamate and the respective metal tetrachloride in acetonitrile. The pentakis-compound Ta[S2CN(CH2)4]5 was also prepared. Spectroscopic (u.v., visible, and i.r.) and magnetic susceptibility studies were carried out on the compounds. The niobium, molybdenum, and tungsten compounds appear to be eight-co-ordinate.
27 citations
27 citations
TL;DR: In this article, the reaction of molybdenum (V) oxidetrichloride with aliphatic nitriles (RCN, R = Me, Et, Pr) results in the formation of the complexes, MoOCl 3, 2RCN.
27 citations