Mercury hydride

The Addition of Tin and Mercury Hydrides to Activated Double Bonds... 

Compare atomic absorption (both flame and graphite furnace), ICP, flame photometry, cold vapor mercury, hydride generation, atomic fluorescence, and spark emission in terms of ... 

Mannich reaction, 1, 10 7, 3 Meerwein arylation reaction, 11, 3 24, 3 Meerwein-Ponndorf-Verley reduction, 2, 5 Mercury hydride method to prepare radicals, 48, 2... 

Addition of organometallic compounds to unsaturated esters 5-20 Addition of tin and mercury hydrides to unsaturated ketones 5-22 Free-radical addition of carboxylic esters to olefins... 

M. Hehenberger, B. Laskowski, E. Brandas, Weyl s Theory Applied to Predissociation by Rotation. I. Mercury Hydride, J. Chem. Phys. 65 (1976) 4559. 

W.C. Stwalley, Mass-Reduced Quantum Numbers Application to the Isotopic Mercury Hydrides, J. Chem. Phys. 63 (1975) 3062. 

Perkin-Elmer Corp., Mercury/Hydride System, Report 1876/6.79, Norwalk, CT, 1987. 

Craig, P.J., D. Mennie, M.I. Needham, O.F.X. Donard, and F. Martin. 1993. Mass spectroscopic nuclear magnetic resonance evidence confirming the existence of methyl mercury hydride. J. Organomet. Chem. 447 5-8. 

These two complex hydrides have been used also in inorganic syntheses. Lithium aluminum hydride may be used to prepare unstable hydrides in ether at low temperatures from the appropriate halides cadmium hydride and mercury hydride (Chap. 2) have been so prepared. A number of additional borohydrides, aluminum hydrides, and even a gallohydride (LiGaH4) have been reported. 

Alkyl mercury halides and alkyl mercury acetates are quite stable, but reduction with sodium borohydride leads to highly unstable alkyl mercury hydrides, which collapse at room temperature or in the presence of light to yield alkyl radicals. One other product is mercury metal and you might think you would get H as well but this is too unstable to be formed and is captured by something else (X)—you will see what X is in a moment. This initial decomposition of RHgH initiates the chain but its propagation is by the different mechanism shown below. 

Unfortunately, radicals derived from alkylmercuries are even more limited in what they will react with than radicals made from alkyl halides by the tin hydride method. Styrene, for example, cannot be used to trap alkylmercury-derived radicals efficiently because the radicals react more rapidly with the mercury hydride (which has an even weaker metal-H bond than Bi SnH) than with the styrene. 

---