Combined QTAIM and ETS-NOCV investigation of the interactions in ClnM[PhB(NtBu)2] complexes with M = Si & Ge (n = 0), As & Sb (n = 1), Te & Po (n = 2).

In this work, the nature of the chemical interactions between the metalloid atom (M = Si, Ge, As, Sb, Te, Po) and the nitrogen atoms in the bora-amidinate (bam) complexes (ClnM[PhB(NtBu)2]) are investigated, mainly via density-based indices. The descriptors used are derived using the quantum theory of atoms in molecules and natural orbitals for chemical valence approaches. It is shown that the strongest interaction is achieved with silicon. Indeed, it is generally the lightest metalloid in a particular group of the periodic table (i.e., Si, As, and Te for groups 14-16, respectively) that exhibits the strongest bond in the bam complex. This suggests that the atomic radius of the metalloid is a useful parameter for predicting the bonding strength. Extended transition state (ETS) decomposition results indicate that the interactions are more electrostatic than due to orbital interactions.