Combined DFT, QCISD(T), and G2 mechanism investigation for the reactions of carbon monophosphide CP with unsaturated hydrocarbons allene CH2CCH2 and methylacetylene CH3CCH.

The possible reaction product distribution and mechanism of carbon monophosphide CP with unsaturated hydrocarbons allene CH₂CCH₂ and methylacetylene CH₃CCH are investigated at the B3LYP/6-311+G(d,p), QCISD(T)/6-311++G(2df,2p), and G2 levels of theory. Corresponding reactants, products, intermediates, and interconversion and dissociation transition states are located on the reaction potential energy profiles. Computation results show that in the reaction of CP with CH₂CCH₂ the dominant reaction product should be species CH₂CCHCP. Also, we can suggest species HCCCH₂CP as a secondary reaction product despite of only minor contribution to reaction products. In the reaction of CP with CH₃CCH, the primary and secondary products are suggested to be two important molecules HCCCP and CH₃CCCP, respectively. The predicted mechanisms for the two reactions are not in parallel with the reactions of CN with allene CH₂CCH₂ and methylacetylene CH₃CCH given in previous studies. The present calculations provide some useful information for future possible experimental isolation and observation for some interesting unsaturated carbon–phosphorus-bearing species. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2007 [ABSTRACT FROM AUTHOR]