DFT study of the full catalytic cycle for the propene hydroformylation catalyzed by a heterobimetallic HPt(SnCl₃)(PH₃)₂ model catalyst

Abstract

DFT calculations were carried out to study the full catalytic cycle for the hydroformylation of propene, catalyzed by the heterobimetallic model catalyst trans-Pt(H)(PH(3))(2)(SnCl(3)). Before the study of the full catalytic cycle, the performance of six pure GGA, one GGA with inclusion of dispersion corrections, four hybrid-GGA, and three meta-GGA exchange correlation functional to describe a model reaction promoted by Pt-Sn catalyst were assessed. It is shown that the BP86 and GPW91 functionals, using extended basis set, provides reliable energetic results when compared with the CCSD(T) calculations. All intermediates and transition states along the elementary steps of the entire catalytic cycle were located and the energies involved in the catalytic cycle calculated using BP86 functional. The solvent effects along the entire catalytic cycle were evaluated using the polarizable continuum model. In contrast with the rhodium catalysts, the regioselectivity of the hydroformylation is set at the carbonylation step. The hydrogenolysis is the rate determining step of the entire cycle, with the activation energy of approximately 21 kcal mol(-1) in agreement with the experimental value of approximately 25 kcal mol(-1). The trans effect of the SnCl(3)(-) ligand seems to be pronounced only in the first step of the catalytic cycle, facilitating the insertion of the olefin into the Pt-H bond trans to it. The analysis of the stationary points obtained along each elementary step of the catalytic cycle is carried out separately and discussed. The BP86/cc-pVTZ/SBKJC results shows that the pathway leading to the linear aldehyde is preferred, being in agreement with the experimental findings.

Isomerization–Hydroformylation Tandem Reactions

“…142 Whether the olefin insertion or the subsequent carbonylation is the regiochemistry determining step is still under discussion. 143,144 In the early 1970s Clark and Kurosawa intensively investigated the mechanism of the stoichiometric and catalytic isomerization of terminal and internal olefins (1-butene, allyl ethers) with phosphine-modified platinum hydrido complexes of the type trans-[HPt(PR 3 ) 2 (acetone)]X and trans-[HPt-(ClO 4 )(PPh 3 ) 2 ]. 145 Later on, Toniolo et al showed that the isomerization rate is strongly dependent on the temperature.…”

“…Frequently, this problem has been overcome by use of styrenes as model substrates, which direct the hydroformylation to the position next to the aryl ring . Whether the olefin insertion or the subsequent carbonylation is the regiochemistry determining step is still under discussion. , …”

Az ón(II)-halogenidek koordinációs kémiájának jelentősége a platinakatalizált hidroformilezési reakcióban

“…A fõbb elemi lépések megegyeznek, függetlenül attól, hogy a katalizátor kobalt, 14 ródium, 15 vagy platina 16 központi atomra épül (2. Ábra).…”