Serge Schreiner

Carbon Dioxide Reduction via Homogeneous Catalytic Synthesis and Hydrogenation of N,N-Dimethylformamide.

Abstract : The previously reported catalytic reaction between CO2, H2, and (CH3)2NH to yield N,N-dimethylformamide (DMF) has been found to produce also trimethylamine (TMA) in the presence of several Ru, Os, Rh, Ir and Pt complexes. In separate experiments, the hydrogenation of DMF, catalyzed by the same or other complexes, also gave TMA. Thus, evidence is presented for the overall catalytic reduction of CO2 the the methyl group (-CH3, incorporated in TMA). Keywords: Carbon dioxide, Hydrogenation, Homogeneous catalysis, N, N Dimethylformamide, Ethyl radicals.

Synthesis and nuclear magnetic resonance solution studies of zerovalent nickel-carbonyl-dppm complexes

Abstract Three nickel-carbonyl-dppm complexes, Ni(CO) 2 (η 1 -dppm) 2 , Ni 2 (μ-dppm) 2 (μ-CO)(CO) 2 and Ni 2 (μ-dppm) 2 (CO) 4 have been prepared by minor modifications of a single synthetic procedure. The complexes were characterized in the solid state by IR analysis and in solution by 31 P NMR analysis. In solution, at 25 °C, Ni(CO) 2 (η 1 -dppm) 2 rearranges to initially form Ni 2 (μ-dppm) 2 (μ-CO)(CO) 2 , CO and dppm followed by the subsequent reaction of Ni 2 (μ-dppm) 2 (μ-CO)(CO) 2 with CO to yield Ni 2 (μ-dppm) 2 (CO) 4 . Carbon monoxide gas uptake measurements were conducted to determine the extents of the interconversions of the three nickel-carbonyl-dppm complexes at 25 °C and 700 torr. Reaction of CO with Ni(CO) 2 (η 1 -dppm) 2 yielded a fourth zerovalent complex, Ni(CO) 3 (η 1 - dppm).

CHARACTERIZATION OF LOW-VALENT NICKEL COMPLEXES STABILIZED BY BIS(DIPHENYLPHOSPHINO)METHANE USING MULTINUCLEAR NMR AND IR SPECTROSCOPY

Experimental method for the synthesis of zero-valent nickel complexes containing bis(diphenylphosphino)methane and identification through NMR and IR spectroscopy; sample data and analysis included.

Reversible homogeneous catalysis of carbon dioxide hydrogenation/reduction at room temperature and low pressures

Abstract : A platinum complex, ?Pt2(u-PCP)3 (PCP = (C6H5)2PCH2P(C6H6)2, catalyzes the synthesis of N, N-dimehtylformamide (DMF) from CO2, H2 and (CH3)2NH in toluene solution at 25-100C and total pressures of 0.96-114 atm of the three reactant gases. The turnover numbers, DMF/complex/day, range from 9 at 25C and 0.96 atm to 1375 at 100 C and 114 atm. The homogeneous synthesis of DMF is readily reversible by either increasing the temperature, lowering the pressure of the reactants, or both, during the catalytic reaction. The formation of DMF appears to be dependent on the partial pressures of the individual reactants. Separate reactions of the three reactants with (Pt2(u-PCP)3) at ambient conditions (25C, 700 torr) give adducts with (CH3)2NH, but not with CO2 or H2. Keywords: Carbon Dioxide, Hydrogenation, Homogeneous Catalysis, N, N dimethylformamide, Platinum, Phosphine Complex.