Hydrogen activation and aldehyde elimination promoted by homogeneous Pt–Sn catalyst: a theoretical study

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

“…The HH bond distance of 0.908 and 0.910 Å are even more elongated as compared with the HH distance of 0.754 Å in the free H 2 molecule. As was observed in a previous study,26 the oxidative addition of H 2 proceeds with an increasing electron donation from the metallic fragment to the antibonding σ* molecular orbital of the H 2 fragment, which is in agreement with the widely accepted mechanism for oxidative addition reactions 65. Further interaction between the incoming H 2 molecule with the acyl fragment generates the dihydride species 9b and 9l, in which the HH bond is completely dissociated.…”

“…The HH bond distances of 0.897 Å and 0.841 Å in 7b and 7l, respectively, in the η 2 –H 2 adduct is lengthened as compared with the free H 2 molecule where the HH bond is 0.754 Å, corresponding to a stretching of ∼15% of the HH bond. In a previous study, we have performed a charge decomposition analysis to evaluate the nature of the PtH 2 interaction in η 2 –H 2 adduct species of Pt‐Sn catalyst 26. It was shown that the lengthening of the HH bond distance is a result of the synergetic interaction, involving population of the antibonding σ* molecular orbital of the H 2 fragment through backdonated charges from the metallic fragment.…”

“…With the aim of providing some fundamental information on the energetic and reaction mechanism appearing along the catalytic cycle for the Pt‐Sn hydroformylation, we have over the past recent years investigated theoretically the steps A–E of the catalytic cycle shown in Figure 1, at the MP4(SDQ)//MP2 level of theory 23–26. In these studies, we have used the heterobimetallic trans ‐Pt(H)(PH 3 ) 2 (SnCl 3 ) compound as a model catalytic species and ethylene as a model substrate.…”

Ab initio energy calculations and macroscopic rate modeling of hydroformylation of higher alkenes by Rh‐based catalyst

“…Another theoretical study on the mechanism of the isomerization of 1‐butene catalyzed by Rh‐complex has been reported by Luo et al15 The quantum mechanical calculations were carried out in the density functional theory framework to evaluate the potential energy profile and the reaction mechanisms involved. Rocha16 studied the reaction mechanisms involved in the last step of the catalytic cycle of the hydroformylation of an alkene promoted by Pt‐Sn catalyst, which is a hydrogenolysis process. Very recently, Cavallotti et al2 reported ab initio computational studies on cyclohexane oxidation leading to kinetic parameters of primary reactions.…”

Ruthenium–tin cluster complexes and their applications as bimetallic nanoscale heterogeneous hydrogenation catalysts

“…The use of tin as a modifier in hydrogenation catalysis has been less studied, but recent studies have shown that the mixing of tin with transition metal catalysts can produce substantial improvements in product selectivities without major losses in activity (Yoshikawa & Iwasawa 1995;Hermans & Johnson 2000;Mallat & Baiker 2000;Gerstosio et al 2001;Hermans et al 2001;Jerdev et al 2002;Johnson et al 2002;Thomas et al 2003;Adams et al 2007cAdams et al , 2008bRuiz-Martinez et al 2007). Tin ligands have also been shown to modify the selectivities of transition metal catalysts under homogeneous conditions (Coupé et al 2000;Rocha 2004;Choudhury & Roy 2008). Some of our recent studies have been focused on the synthesis and chemical properties of ruthenium carbonyl complexes containing tin ligands.…”