Tímea R Kégl1, László Kollár1,2, Tamás Kégl1. 1. Department of Inorganic Chemistry and MTA-PTE Research Group for Selective Chemical Syntheses, University of Pécs, H-7624 Pécs, Hungary. 2. Department of Inorganic Chemistry and János Szentágothai Research Centre, University of Pécs, H-7624 Pécs, Hungary.
Abstract
The mechanism of the carbonylation of diazomethane in the presence of iron-carbonyl-phosphine catalysts has been investigated by means of DFT calculations at the M06/def-TZVP//B97D3/def2-TZVP level of theory, in combination with the SMD solvation method. The reaction rate is determined by the formation of the coordinatively unsaturated doublet-state Fe(CO)3(P) precursor followed by the diazoalkane coordination and the N2 extrusion. The free energy of activation is predicted to be 18.5 and 28.2 kcal/mol for the PF3 and PPh3 containing systems, respectively. Thus, in the presence of less basic P-donor ligands with stronger π-acceptor properties, a significant increase in the reaction rate can be expected. According to energy decomposition analysis combined with natural orbitals of chemical valence (EDA-NOCV) calculations, diazomethane in the Fe(CO)3(phosphine)(η1-CH2N2) adduct reveals a π-donor-π-acceptor type of coordination.
The mechanism of the pan class="Chemical">carbonylation of pan class="Chemical">diazomethane in the presence of pan class="Chemical">iron-carbonyl-phosphine catalysts has been investigated by means of DFT calculations at the M06/def-TZVP//B97D3/def2-TZVP level of theory, in combination with the SMD solvation method. The reaction rate is determined by the formation of the coordinatively unsaturated doublet-state Fe(CO)3(P) precursor followed by the diazoalkanecoordination and the N2 extrusion. The free energy of activation is predicted to be 18.5 and 28.2 kcal/mol for the PF3 and PPh3containing systems, respectively. Thus, in the presence of less basic P-donor ligands with stronger π-acceptor properties, a significant increase in the reaction rate can be expected. According to energy decomposition analysis combined with natural orbitals of chemical valence (EDA-NOCV) calculations, diazomethane in the Fe(CO)3(phosphine)(η1-CH2N2) adduct reveals a π-donor-π-acceptor type of coordination.
Authors: D B Grotjahn; L S Collins; M Wolpert; G A Bikzhanova; H C Lo; D Combs; J L Hubbard Journal: J Am Chem Soc Date: 2001-08-29 Impact factor: 15.419
Authors: Revital Cohen; Boris Rybtchinski; Mark Gandelman; Haim Rozenberg; Jan M L Martin; David Milstein Journal: J Am Chem Soc Date: 2003-05-28 Impact factor: 15.419