Molecular geometries and energetics of mono- and biligated group 2 metal monopositive ions using an improved ASED-MO model Original Research Article

The structural, energetic and spectroscopic properties of the complete series of MLn+ (n = 1 or 2; L = H2O, NH3, CH3OH and CO) and MLLʹ+ (Lʹ = H2O, NH3 and CH3OH) complexes of group 2 metal monopositive ions have been calculated by an improved ASED-MO model. Accurate metal-ligand stretching and ligand-metal-ligand bending potential energy curves were derived for all cationic species. The computed spectroscopic properties (Re, De, ωe and θ) by the new semiempirical computational scheme were found to be in good agreement with those of “state-of-the-art” ab initio calculations, where available. Calculations were consistent with a predominantly ionic character of the bonding in both the mono- and biligated group 2 metal cations. Moreover, they provided evidence for synergic stabilization of the mixed-ligand biligated systems and the existence of trans effect in coordination compounds of main group metal ions.