MOLECULAR INSIGHTS ON THE DIHYDROGEN BOND PROPERTIES OF METAL BOROHYDRIDE COMPLEXES UPON AMMONIATION

Abstract

The dihydrogen bond (DHB) that exists between BHbold dotbold dotbold dotHN containing systems is known for the improved thermodynamic properties of complex hydrides. This study explores the stability and electronic properties of dihydrogen bonds (Hδ−bold dotbold dotbold dotHδ+) that exist between the protic hydrogen, Hδ+ in NH3 and hydridic hydrogen, Hδ− of BH4 in AMgBbold dotbold dotbold dotMB and AMgBbold dotbold dotbold dotAMB complexes (where M = Li, Na, K, Mg and Zn; and A = Amino group) using second order Moller-Plesset perturbation theory (MP2). The effect of metals and ammoniation in varying the nature of the DHB was revealed in quantum theory of atoms in molecule (QTAIM) analysis with the identification of non-covalent interactions. The calculated values of interaction energies were correlated well with the topological results. Furthermore, energy decomposition analysis (EDA), interaction energy and Bader charge analysis were calculated in order to interpret the role of non-bonded interaction on decomposition process. The calculated structural, QTAIM and EDA analysis reveal the presence of non bonded interaction in all the complexes. Overall analysis of the study reported that the process of adding amine group in alkali metal borohydrides increases charge distribution around the dispersion interaction which plays a vital role in hydrogen evolution process.