Solute-hydrogen complexes

Xenon difluoride [4, 5, 7, 8,10] is a white crystalline material obtained through the combination of fluorine and xenon m the presence of light The reagent is commercially available and possesses a relatively long shelf-life when stored cold (freezer) Xenon difluoride is very effective for small-scale fluormation of alkenes and activated nucleophilic substrates. The reactions are usually conducted between 0 °C and room temperature in chloroform or methylene chloride solutions Hydrogen fluoride catalysis is sometimes helpful Xenon difluoride reacts in a manner that usually involves some complexation between the substrate and reagent followed by the formation of radical and radical cation intermediates... 

Transfer hydrogenation of aldehydes with isopropanol without addition of external base has been achieved using the electronically and coordinatively unsaturated Os complex 43 as catalyst. High turnover frequencies have been observed with aldehyde substrates, however the catalyst was very poor for the hydrogenation of ketones. The stoichiometric conversion of 43 to the spectroscopically identifiable in solution ketone complex 45, via the non-isolable complex 44 (Scheme 2.4), provides evidence for two steps of the operating mechanism (alkoxide exchange, p-hydride elimination to form ketone hydride complex) of the transfer hydrogenation reaction [43]. 

Abraham, M. H., P. L. Grellier, D. V. Prior, P. P. Duce, J. J. Morris, and P. J. Taylor. 1989a. A Scale of Solute Hydrogen-bond Acidity Based on log K Values for Complexation in Tetrachloromethane. J. Chem. Soc., Perkins Trans. 2, 699. 

Abraham M, Grellier P, Prior D, Morris J, Taylor P. Hydrogen bonding. Part 10. A scale of solute hydrogen-bond basicity using log values for complexation in tetrachloromethane. J Chem Soc Perkin Trans II 1990 521-529. 

The aerial oxidation of solutions of complexes (330) has been investigated. Chromatography separation led to the identification of products which underwent dehydrogenation of the ethylene bridge (Scheme 31).2413 Such dehydrogenation reactions are inhibited by fluoroalkyl substituents and enhanced by alkyl substituents. Oxidation with hydrogen peroxide removes the ethylene bridge. 

CoH(BH4)(PCy3)2] in benzene solution hydrogenates terminal alkenes and styrene faster than internal alkenes or dienes. Isomerization of terminal alkenes caused a rapid deterioration of the reaction rate.69 An ort/io-metallated triphenyl phosphite complex, for which the structure (20) was proposed, gave a turnover number of more than 300 in the hydrogenation of 1-butene. Isomerization was not observed in this case.70... 

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