| Abstract |
Despite the long history of the investigation of nucleophilic addition to metal-bound isocyanides, some important aspects of the reaction mechanism remain unclear even for the simplest systems. In this work, the addition of the sp(3)-N, sp(2)-N, and mixed sp(2)/sp(3)-N nucleophiles (i.e., HNMe2, HN=CPh2, and H2N-N=CPh2, respectively) to isocyanides C equivalent to NR coordinated to the platinum(II) centers in the complexes cis-[Pt(C equivalent to NCy)(2-pyz)(dppe)](+) (2-pyz = 2-pyrazyl, dmpe = Me2PCH2CH2PMe2) and cis-[PtCl2(C equivalent to NXyl)(C equivalent to NMe)] was studied in detail by theoretical (DFT) methods. The mechanism of these reactions is stepwise associative rather than concerted and it includes the addition of a nucleophile to the isocyanide C atom, deprotonation of the nucleophilic moiety in the resulting intermediate, and protonation of the isocyanide N atom to give the final product. The calculated activation energy (Delta G(not equal)) of all reactions is in the range of 19.8-22.4 kcal/mol. |
