Dihydrogen uptake

Diiridium(I) complexes, dihydrogen uptake, 7, 289 Diiridium(III) polyhydrides, synthesis and reactivity, 7, 410 Diiron carbonyl complexes with cyclopentadienyl ligands... 

Metal-time yields on Co catalysts are also proportional to the dispersion of Co crystallites (10-100 nm in diameter, 0.45-9.5% dispersion) on supported SiOi, AI2O3, TiOi, and mixed-metal oxides (Fig. 3). Cobalt-time yields increase with increasing dihydrogen uptake on all metal oxide supports. Therefore, site-time yields lie in a narrow range (1.6-3.0 x 10" s , at 2000 kPa and 473 K) and do not depend on support or metal disper-... 

Dihydrogen uptake was monitored using a gas burette system. G.C.(M.S.) samples were taken through a silicon septum with a hypodermic syringe. Substrates and products were analysed with G.C. and confirmed with G.C.M.S.. 

This review has focused on the possible roles for metal hydrides on two metalloenzymes which are currently still the focus of active research hydrogenaes and nitrogenases. Besides the obvious role of hydrides being crucial intermediates in the uptake and production of dihydrogen in both these enzymes. 

Courtaulds originally made a product from viscose rayon called Asgard, believed to be produced from a doped viscose fiber, or by treating the viscose fiber with a solution of diammonium dihydrogen phosphate and urea to give an uptake of 1-2% P on the fiber. This treated material was heated to give a black product, stable at temperatures up to 150°C and able to withstand a 1300°C bunsen burner flame for 4 min. The product could be used alone, blended with aramids, or used as a precursor for the production of activated carbon fabrics. 

As described in Section 8.1.3 for the uptake and binding of dihydrogen, a critical balance of electrophilicity and t-back donating ability of the metal is required. 

In the presence of a large excess of olefin, the carbon monoxide uptake approaches 1 mol/mol of HCo(CO)4 and acylcobalt tetracarbonyl complex is obtained, which in turn can be reduced at room temperature to aldehyde by HCo(CO)4 or by dihydrogen ... 

Waterhyacinth plants [Eichhornia crassipes (Mart.) Solms], which infest waterways in many parts of the world, were used as a model system for studying uptake of metal ions by floating acpiatic plants. Observed rates of uptake of manganese(II)-54 and iron(III)-59 by water hyacinth compare favorably with the values expected based upon a coordination model control by chelation with dihydrogen ethylenediamine- tetraacetate ion and control by metal(II) carbonate solubility. Agreement depends upon the assumption of the reduction of iron(III) species by the plant. 

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