A DFT Study on the Co-polymerization of CO2 and Ethylene: Feasibility Analysis for the Direct Synthesis of Polyethylene Esters.

The co-polymerization of CO2 with the non-polar monomer ethylene, though highly desirable, still presents a challenge whereas the palladium-catalyzed CO/C2 H4 co-polymerization is well understood. Building on this analogy, the goal of this study was to elucidate the feasibility of developing suitable catalysts for co-polymerizing CO2 with ethylene to polyethylene esters. Computational methods based on density functional theory were hereby employed.

NH3 Synthesis in the N2/H2 Reaction System using Cooperative Molecular Tungsten/Rhodium Catalysis in Ionic Hydrogenation: A DFT Study.

The ionic hydrogenation of N2 with H2 to give NH3 is investigated by means of density functional theory (DFT) computations using a cooperatively acting catalyst system. In this system, N2 binds to a neutral tungsten pincer complex of the type [(PNP)W(N2)3] (PNP=pincer ligand) and is reduced to NH3. The protons and hydride centers necessary for the reduction are delivered by heterolytic cleavage of H2 between the N2-tungsten complex and the cationic rhodium complex [Cp*Rh{2-(2-pyridyl)phenyl}(CH3 CN)](+).

Hydrogenation of carbon dioxide to methanol using a homogeneous ruthenium-Triphos catalyst: from mechanistic investigations to multiphase catalysis.

The hydrogenation of CO to methanol can be achieved using a single molecular organometallic catalyst. Whereas homogeneous catalysts were previously believed to allow the hydrogenation only formate esters as stable intermediates, the present mechanistic study demonstrates that the multistep transformation can occur directly on the Ru-Triphos (Triphos = 1,1,1-tris(diphenylphosphinomethyl)ethane) centre. The cationic formate complex [(Triphos)Ru(η-OCH)(S)] (S = solvent) was identified as the key intermediate, leading to the synthesis of the analogous acetate complex as a robust and stable precursor for the catalytic transformation.

Stereocontrol in dinuclear triple lithium-bridged titanium(IV) complexes: solving some stereochemical mysteries.

Compounds 1 a-f-H2 form "monomeric" triscatecholate titanium(IV) complexes [Ti(1 a-f)3](2-), which in the presence of Li cations are in equilibrium with the triple lithium-bridged "dimers" [Li3(Ti(1 a-f)3)2](-). The equilibrium strongly depends on the donor ability of the solvent. Usually, in solvents with high donor ability, the stereochemically labile monomer is preferred, whereas in nondonor solvents, the dimer is the major species.