Ab initio MP2 calculations of the products of acetylene addition to HgCl2

Gas-phase reaction of acetylene with HgCl2 resulting in beta -chlorovinylme rcury derivatives and their interaction with Cl- and I- anions and KI molec ule was studied by tile ab initio MP2 method with the Dunning-Hay double ze ta basis set and LanL pseudopotential for Hg, K, and I atoms. The reaction was shown to proceed via a pi -complex of acetylene and HgCl2 (the calculat ed enthalpy of formation is -6.5 kcal mol(-1)). According to calculations, tile activation energy of formation of cis-beta -chlorovinylmercury chlorid e from acetylene and HgCl2 is 31 kcal mol(-1). Chloride and iodide anions a nd KI molecule are readily added to both cis- and trans-isomer of beta -chl orovinylmercury chloride to give stable species.