Substitution effect of superhalogens in MX3MCN-YF and MX3MCCY-NH3 complexes: Comparison with XMCN-YF and XMCCY-NH3

The complexes MX3MCN-YF and MX3MCCY-NH3 (M = Be, Mg, Ca; X = F, Cl, Br; Y = H, Cl, Li) have been studied at the MP2(FC)/6-311++G(2d,2p) level. For comparison, XMCN-YF and XMCCY-NH3 complexes were also investigated. The superhalogen MX3 is favorable for the formation of complexes when it exists in the electron donor but unfavorable in the electron acceptor. The interaction strength is related with the nature of M and X atoms. With the increase of M atomic mass, the interaction strength becomes larger for MX3MCN-YF but smaller for MX3MCCY-NH3. The effect of X on the interaction strength is smaller than that of M. The electrostatic potential analyses show that the electron-withdrawing ability of the superhalogen weakens in the electron donor and acceptor with respect to the halogen atom.