DIALKYLARGENTATE(I) DECOMPOSITIONS AND THE HETEROGENIZATION OF ANALOGOUS COMPLEXES FOR CATALYST PREPARATIONS.

摘要

Lithium di-n-butyl(tri-n-butylphosphine)argentate(I) (2) and other organoargentate(I) complexes have been prepared and their mechanism of thermal decomposition studied. Chemical characterization of 2 by reaction first with dibromoethane and then iodine yielded only l-iodobutane, showing that 2 was formed quantitatively. ('13)C and ('31)P NMR spectra of lithium dimethyl(tri-n-butylphosphine)argentate(I) are described which support this conclusion. Dilithium trimethyl(tri-n-butylphosphine)argentate(I) was also identified by ('13)C NMR. Analysis of the products of thermal decomposition of 2 suggests that the observed thermal stabilization of 2 with respect to the rapid thermal decomposition of n-butyl(tri-n-butylphosphine)silver(I) (1) is the result of an altered mechanism for carbon-silver bond cleavage. Lithium di-n-butyl(tri-n-butylphosphine)argentate(I) is proposed to decompose to give products derived from n-butyl radicals and n-butyllithium. The principle thermal decomposition products from 2 were octane (26%), butane (71%) and 1-butane (3%). Crossover experiments in which mixed lithium n-butyl(n-pentyl)argentate(I) was thermally decomposed yielded a statistical distribution of coupled products. Substitution of magnesium bromide for lithium had no effect on the product mixture from these thermal decomposition reactions. Kinetics of decomposition of 2 were first order in 2. Other possible pathways for decomposition of organoargentate(I) complexes are discussed and the suggested mechanism for this thermal decomposition reaction is compared to similar organocopper(I) and organogold(I) chemistry.;Thermolysis of insoluble organometallic compounds has led to the preparation of heterogeneous catalysts. The decomposition of an intermediate polystyrylpalladium(II), which was formed from modified polystyryllithium compounds and any one of several palladium(II) complexes, yielded supported palladium(O) on the organic solid. Polystyrylpalladium(O) was also prepared from the direct reduction of palladium(II) complexes with polystrylanthracene radical anion. Heterogeneous catalysts formed by these procedures were shown to have hydrogenation activities and selectivities for alkynes and alkenes that were comparable to palladium-on-carbon catalysts. Isomerizations of terminal alkenes were catalyzed by the supported palladium(O) catalysts. Polar solvents generally enhanced the catalytic activity of PS-Pd('0). However, it was also necessary that the solvents swell the PS-Pd('0), thus permitting access to the catalytic sites within the polymer matrix. The palladium(O) was not extracted from the support under normal hydrogenation conditions. Elemental analysis, electron microscopy and ESCA were used for the characterization of these supported catalysts.;Methylsilver(I) complexes have been studied by ('1)H, ('7)Li, ('13)C and ('31)P NMR spectroscopy and the methylsilver(I), dimethylargentate and tri-trimethylargentate complexes have been identified. Several possible structures of each complex are presented. The activation parameters for intermolecular methyl exchange were determined from the complete line shape analysis of ('13)C dynamic NMR spectra of the three complexes.