Tracing the acid-base catalytic properties of MON(2)O mixed oxides (M = Be, Mg, Ca; N = Li, Na, K) by theoretical calculations

The stability and acid-base properties of MON(2)O mixed oxides (where M = Be, Mg, Ca; N = Li, Na, K) are studied by using ab initio methods. It is demonstrated that (i) the basicity of such designed systems evaluated by estimation of electronic proton affinity and gas-phase basicity (defined as the electronic and Gibbs free energies of deprotonation processes for [MON(2)O]H(+)) were found significant (in the ranges of 272–333 and 260–322 kcal/mol, respectively); (ii) in each series of MOLi(2)O/MONa(2)O/MOK(2)O, the basicity increases with an increase of the atomic number of alkali metal involved; (ii) the Lewis acidity of the corresponding [MON(2)O]H(+) determined with respect to hydride anion (assessed as the electronic and Gibbs free energies of H(−) detachment processes for [MON(2)O]H(2)) decreases as the basicity of the corresponding oxide increases. The thermodynamic stability of all [MON(2)O]H(2) systems is confirmed by estimating the Gibbs free energies for the fragmentation processes yielding either H(2) or H(2)O.