Mechanistic investigation of platinum-catalysed hydroformylation of propene: A density functional study

Abstract

The mechanism of hydroformylation of propene in the presence of both cis-PtH(SnCl 3)(PH 3) 2 and trans-PtH(SnCl 3)(PH 3) 2 catalysts has been investigated. A density functional study has been carried out for all of the elementary steps of the catalytic cycle, i.e. for the alkene coordination, for its insertion into the Pt–H bond, carbon monoxide activation and its subsequent insertion into the Pt–alkyl bond. Finally, the product forming step, the dihydrogen activation and aldehyde elimination have been investigated. It has been found that the regioselectivity of hydroformylation is determined in the olefin insertion step. The computed ratio of the linear regioisomer, n-butanal is predicted to be 83% when solvation corrections were employed, being in very good agreement with the experimental result. Among the elementary steps the hydrogenolysis has been found to be the slowest followed by the migratory carbon monoxide insertion step. Due to the crucial role of the trichlorostannato ligand the electronic effects of SnCl 3 has been analysed employing the charge decomposition analysis (CDA), the natural bond orbital (NBO) and the atoms in molecules (AIM) methods.