Molybdenum complex compounds, anions, with

In a similar manner, Jt-allyl complexes of manganese, iron, and molybdenum carbonyls have been obtained from the corresponding metal carbonyl halides [5], In the case of the reaction of dicarbonyl(r 5-cyclopentadienyl)molybdenum bromide with allyl bromide, the c-allyl derivative is obtained in 75% yield in dichloromethane, but the Jt-allyl complex is the sole product (95%), when the reaction is conducted in a watenbenzene two-phase system. Similar solvent effects are observed in the corresponding reaction of the iron compound. As with the cobalt tetracarbonyl anion, it is... 

On treatment with CsF, 74j yields the salt 75a 119). The same anion together with a cation containing a dioxaphospholane ring 75b has been synthesized from thermolysis of the aminoiminodiphosphorane 74n 229). Compound 74j forms a stable donor-acceptor complex with trimethylphosphane 119). Reduction of 74j with trimethylsilyldiphenylphosphane affords the 2 -dioxaphospholane 73a, which serves as a phosphane ligand in the molybdenum complex 76 229). The phosphane ligands are in cis-positions. 

Vanadium, the first element in Subgroup oA, and neighbour to chromium, is found in association with molybdenum in certain complex compounds. For example, when boiling solutions of molybdo-oxalates react with vanadium pentoxide, crystalline products are obtained which are thought to be substituted vanadates containing the complex anion... 

Various metal-metal single o-bonded complexes have been obtained by the reaction of metal carbonyls with metal-carbon o-bonded porphyrins or by the reaction of metal carbonyl anions and chlorometalloporphyrins (Scheme 14). For example, the reaction of dimanganese carbonyl and methyl indium(III) porphyrin gives manganese pen-tacarbonyl indium porphyrin In(Por)Mn(CO)5. The same compound is isolated when chloroindium porphyrin is allowed to react with the manganese pentacarbonyl monoanion. Various iron, cobalt, tungsten, and molybdenum complexes have been prepared by these two methods. 

The recommended daily dietary doses of copper are 0.4-0.7 mg for children under 1 year, 0.7-2.0 mg for children aged 1 to 10 years, 1.5-2.5 mg for adolescents and 1.5-3.0 mg for adults. Resorption of copper and its retention in the body depend on the chemical form in which this element is present in the diet. Experiments on laboratory animals have shown a higher utilisation of copper in the form of neutral and anionic complexes contained in plant material than in the form of copper sulfate. Availability of copper increases the presence of proteins and amino acids in the diet. Also, carboxylic and hydroxycarboxylic acids stimulate resorption of copper. In contrast, higher doses of ascorbic acid, fructose, molybdenum, sulfur compounds and zinc significantly reduce the resorption of copper. Ascorbic acid reduces cupric compounds to slightly soluble cuprous compounds. The effect of phytic acid and dietary fibre on copper resorption is, in comparison with the effect of these components in zinc, less pronounced. 

The reaction of anionic metal complexes 162 with a-chloro ketones, esters, or tertiary amides occurring under chloro-metal exchange is an appropriate method for the preparation of molybdenum and tungsten enolates. The reaction fails with the corresponding a-bromo compounds. In order to obtain tungsten enolates, which are substituted in a-position, a-methanesulfonyloxy-substituted esters are suitable starting materials. The tungsten and molybdenum complexes 163 were fully characterized as C-bound // -enolates (Scheme 2.47) [162]. 

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