Gas phase thermolysis of allylphosphines, kinetic study

Palladium nanoparticles in ionic liquids stabilized by mono-phosphines. Catalytic applications

Palladium nanoparticles generated from organometallic complexes in the presence of functionalized mono-phosphines (L1-L3), in both THF and imidazolium-based ionic liquids (ImILs), were successfully synthesized. Depending on the phosphine and solvent nature, PdNPs with different extent of aggregation were observed. Actually, the ligand L1, P(CH2CH2CH2Ph)3, led to small and well-dispersed nanoparticles in both ILs, [BMI][PF6] and [EMI][HP(O)2OMe], in contrast to more agglomerated PdNPs obtained in THF. PdNPs in ILs were catalytically active and chemoselective in C-C cross-coupling (Suzuki-Miyaura and Heck-Mizoroki) and hydrogenation reactions. Well-defined Pd(0) and Pd(II) organometallic complexes containing L1, [PdCl2(L1)2] and [Pd(ma)(L1)2], were also prepared for comparative purposes.

Computational tests of models for kinetic parameters of unimolecular reactions of organophosphorus and organosulfur compounds

A computational study of the kinetics of isomerization and elimination reactions of organophosphorus and organosulfur reactions is presented with a view to characterizing the predictive capabilities of widely applied techniques for processes that pertain to the destruction of chemical warfare agents. A set of 22 reactions has been studied, and the results have been compared to experimentally derived data. The BMK functional and the MG3S basis set have been used to compute minimum energy paths. Corrections have been added from CBS-QB3, CASSCF, and CASMP2 calculations. Thermal rate constants at experimental temperatures have been calculated with canonical variational transition state theory and small-curvature tunneling theory. The quality of these results may depend on recrossing of the variational transition state, the amount of radical or diradical character found in the minimum energy paths, or the accuracy of barrier heights.

A theoretical study of the formation of phosphaacetylene by thermolysis of triallylphosphine

A theoretical study of the decomposition of triallylphosphine into phosphaacetylene at the B3LYP/6-311++G(3df,2p) level has shown that the most likely mechanism involves two retroene eliminations of propene leading to vinylphosphaacetylene. Two mechanisms can account for the formation of HCP from vinylphosphaacetylene, either by a 1,2 or a 1,3 hydrogen shift. The first pathway was found to be the most favored kinetically. It is quite similar to the pathway proposed for the thermal decomposition of vinylacetylene into acetylene in the shock tube.