Molecular Orbital Study of Flouroaryl Substituted Amino-Borane Dimers: Geometry, Energetics and Reactivity

The electronic properties in terms of HOMO-LUMO energy, electronegativity, hardness and electrophilicity index have been calculated and discussed in the framework of Unrestricted Hartee-Fock (UHF), semi-emperical parametric method (PM3) for six fluoro-substituted aminoborane dimers, viz. [Me2B-μ-N(H)ArF]2 (Ar: 4-C6H4F (1), 2-C6H5F (2); 3,5-C6H3F2 (3); 2,3,4,5-C6HF4 (4); 2,3,5,6-C6HF4 (5) and C6F5 (6)). The calculated parameters mentioned above have been compared with the available experimental and other theoretical estimates. The results are in excellent agreement with the reported estimates. The geometrical parameters calculated are also in good agreement with available experimental and theoretical values. The chemical reactivity is also discussed in terms of electrophilicity index (ω) values.

On the Power of Geometry over Tetrel Bonds

Tetrel bonds are noncovalent interactions formed by tetrel atoms (as σ-hole carriers) with a Lewis base. Here, we present a computational and molecular orbital study on the effect of the geometry of the substituents around the tetrel atom on the σ-hole and on the binding strengths. We show that changing the angles between substituents can dramatically increase bond strength. In addition, our findings suggest that the established Sn > Ge > Si order of binding strength can be changed in sufficiently distorted molecules due to the enhancement of the charge transfer component, making silicon the strongest tetrel donor.