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One example is titanium dihydride, which forms when titanium sponge is heated to 400-700 °C under an atmosphere of hydrogen. These reactions typically require high surface area metals. The direct reaction of metals with H 2 is a step in catalytic hydrogenation. For solutions, classic example involves Vaska's complex: [7]
One example is triethoxysilane: HSiCl 3 + 3 EtOH → HSi(OEt) 3 + 3 HCl. Organohydrosilanes can be prepared by partial hydrosilation of silane itself: SiH 4 + 3 C 2 H 4 → HSi(C 2 H 5) 3. In the laboratory, hydrosilanes classically are prepared by treating chlorosilanes with hydride reagents, such as lithium aluminium hydride:
The reaction is driven by the thermodynamic properties of the intermediates and the products. Several other mechanisms have been proposed for this reaction, including a radical mechanism as well as a mechanism involving an aluminium hydride species. The commonly accepted direct hydride transfer is supported by experimental and theoretical data. [6]
One hydride serves as the hydride source, and the other serves as a proton source. [2] In the case of ionic hydrogenation, a dihydride complex is regenerated by hydrogen gas following hydrogenation. Typical catalysts are tungsten or molybdenum complexes. An example of such a catalyst is CpMo(CO) 2 (PR 3)(OCR' 2)]+ where M = W or Mo. [7]
Classical transition metal hydride feature a single bond between the hydrogen centre and the transition metal. Some transition metal hydrides are acidic, e.g., HCo(CO) 4 and H 2 Fe(CO) 4 . The anions potassium nonahydridorhenate [ReH 9 ] 2− and [FeH 6 ] 4− are examples from the growing collection of known molecular homoleptic metal hydrides ...
In general, complex metal hydrides have the formula M x M' y H n, where M is an alkali metal cation or cation complex and M' is a metal or metalloid.Well known examples feature group 13 elements, especially boron and aluminium including sodium aluminium hydride, NaAlH 4), lithium aluminium hydride, LiAlH 4, and lithium borohydride, (LiBH 4).
Cascade reactions are often key steps in the efficient total synthesis of complex natural products. The key step in Heathcock's synthesis of dihydroprotodaphniphylline features a highly efficient cascade involving two aldehyde/amine condensations, a Prins-like cyclization, and a 1,5-hydride transfer to afford a pentacyclic structure from an acyclic starting material.
The hydrogen atoms occupy interstitial sites in palladium hydride. The H–H bond in H 2 is cleaved. The ratio in which H is absorbed on Pd is defined by = [] [].When Pd is brought into a H 2 environment with a pressure of 1 atm, the resulting concentration of H reaches x ≈ 0.7.