INVESTIGATION OF THE HYDROGENOLYSIS OF LINEAR HYDROCARBONS AND THE SYNTHESIS AND CHEMISTRY OF DIIRON DIPHENYLPHOSPHIDO COMPLEXES.

摘要

This dissertation is divided into two parts. The first part involves an investigation of the mechanism of the hydrogenolysis of linear hydrocarbons, a catalytic reaction that is the basis for the catalytic reforming of petroleum. The second part involves the synthesis and chemistry of diiron bridging diphenyphosphido complexes.; The hydrogenolysis of n-octane and 1-octene in the presence of H(,2) over heterogeneous Co, Ru, and Ni catalysts produces product distributions consistent with a mechanism in which C-C bond breaking in hydrogenolysis is the reverse of C-C bond formation in the Fischer-Tropsch synthesis. This mechanism is in contrast to the currently accepted mechanism of hydrogenolysis which involves extensive dehydrogenation of adsorbed hydrocarbon fragments.; Treatment of the dianion {lcub}Fe(,2)(CO)(,8){rcub}('2-) with one equivalent of chlorodiphenylphosphine led to the formation of two diiron bridging diphenylphosphido monoanions. The first, {lcub}Fe(,2)(CO)(,8)((mu)-PPh(,2)){rcub}('-), contains no metal-metal bond, while the second complex, {lcub}Fe(,2)(CO)(,6)((mu)-CO)((mu)-PPh(,2)){rcub}('-) does have a metal-metal bond and bridging CO ligand.; Alkylation of the first monoanion produces metal-metal bonded acyl and bridging acyl complexes. The mechanism of this reaction is believed to involve a metal-promoted alkyl migration. Alkylation of the second monoanion produces metal-metal bonded bridging alkoxymethylidyne complexes. The chemistry of these neutral diiron bridging diphenylphosphido complexes was studied.; Photolytic decarbonylation of the diiron bridging acyl complexes was investigated. Photolysis of the methoxymethyl derivative produced a diiron complex containing a methoxymethyl alkyl ligand; in solution this complex reaches equilibrium with a complex containing bridging methoxymethylene and hydride ligands via (alpha)-hydride migration. Photolysis of the benzyl derivative produced a diiron complex containing a (eta)('3,4)-benzyl ligand. The complex is stereochemically nonrigid in solution; a low temperature ('1)H NMR study showed the "frozen" structure was not obtained at -90(DEGREES)C. Photolysis of alkyl derivatives containing (beta)-hydrogen led to the formation of the corresponding alkenes, alkanes, and aldehydes. The mechanism for their formation is thought to involve (beta)-hydride elimination from an intermediate alkyl complex.