Tantalum complexes with silyls

Treatment of tantalum hydride complexes with hexamethylsilacyclopropane at 65 °C in the presence of a Lewis base gave the corresponding silyl-tantalum compounds in excellent yield. It appears that this reaction takes place via direct insertion of dimethylsilylene into the tantalum-hydride bond, which would make it the first example of silylene trapping by a transition-metal substrate (Equation (15)) <87JA6210>. 

Niobium and tantalum belong to the metals that are able to bind dinitrogen. The development of this area was first due to Schrock and coworkers, who in 1982 could obtain stable tantalum /U.-N2 compounds in high yields by reducing Alkylidene complexes under dinitrogen at normal pressure. This route can be circumvented in a single pot synthesis by reacting the pentahalides with silylated hydrazines (equation 12). 

Properties M.w. 184.31 sp.gr. 0.993-0.997 b.p. 95-97 C (13 mm Hg) ref. index 1.579 Toxicology TSCA listed Uses Reducing agent for prep, of silyl-substituted alkylidene complexes of tantalum, in ionic reduction of enones to sat. ketones, in reductive cyclization of unsat. ketones, for esters in presence of zinc hydride catalyst, for o-halo ketones in presence of Mo(0), reduction of thio esters to ethers, esters to alcohols with Rh catalysis, in assym. reduction of methyl ketones, reductive cleaving of allyl acetates Manuf./Distrib. ABCR http //www.abcr.de, Alfa Aesar http //www.aifa.com-. Digital Spec. Chems. http //www.digHaichem.com, Fluorochem USA... 

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