Theoretical investigation of the reactivity of copper atoms with OCS: comparison with CS2 and CO2.
The reaction mechanism of the Cu atom with OCS and CO2 has been studied by means of density functional method (B3LYP). The overall energetics has been refined at the CCSD(T) level. In the case of the Cu + OCS reaction, the CS insertion route is found much more favorable than the CO insertion one. This later reaction is direct and involves an activation energy of 83.3 kcal/mol and is endothermic by 50.0 kcal/mol at the CCSD(T) level. The insertion into the CS bond proceeds through the eta1s and eta2cs coordination species as intermediates and is found exothermic by about 20 kcal/mol. The highest transition structure along this route is only 11.5 kcal/mol higher in energy than the reactant's ground states. In the case of the Cu + CO2 reaction, the insertion route into the CO bond is also found direct but with a lower endothermicity (30.6 kcal/mol) and smaller activation energy (61.1 kcal/mol) than that into the CO bond of OCS. In all cases, the insertion mechanism proceeds simultaneously with electron transfer from the Cu atom to OCS (or CO2) molecule.
Dobrogorskaya
Yana
Y
Laboratoire de Physico-Chimie Moléculaire (UMR 5803 CNRS), Université Bordeaux I, 351, cours de la Libération, F-33405 Talence Cedex, France.
Mascetti
Joëlle
J
Papai
Imre
I
Hannachi
Yacine
Y
D003300:Copper / Q000737:chemistry*; D008956:Models, Chemical
D003300:Copper