Enhancing effect of metal coordination interaction on pnicogen bonding

Abstract

The ternary complexes ML∙∙∙PyZX2∙∙∙NH3 (ML = CuCl, CuCN, AgCN, and AuCN; Z = P, As, and Sb; X = H and F) have been investigated with quantum chemical calculations. The results showed that the existence of coordination interaction has a prominent enhancing effect on the strength of pnicogen bonding. Even in ML∙∙∙PySbH2∙∙∙NH3, ML∙∙∙PyAsF2∙∙∙NH3, and ML∙∙∙PySbF2∙∙∙NH3, the pnicogen bond varies from a purely closed-shell interaction to a partially covalent interaction. The coordination interaction results in the enlargement of the σ-hole on the pnicogen atom and thus the enhancement of pnicogen bonding. In addition, the contribution of orbital interaction is also important.

Tweaking the Charge Transfer: Bonding Analysis of Bismuth(III) Complexes with a Flexidentate Phosphane Ligand

“…A relatively new congener of noncovalent interactions is the pnictogen bond (PnB), − which (in analogy with the IUPAC definition of a halogen bond) can be defined as an attractive interaction between the electron-deficient region of a pnictogen (group 15 element) called a pnictogen bond donor and a Lewis base (pnictogen bond acceptor, acting as an electron pair donor) . In the past few years, the potential of PnB in structural assembly, supramolecular architecture, anion sensing, (organo)­catalysis, and molecular recognition has also been highlighted. ,− On the basis of thorough computational studies, ,,− pnictogen bonding is chiefly electrostatic in nature (attraction between the oppositely charged regions around the two centers). Moreover, charge transfer effects (donation from the lone pair of the Lewis base into the σ*-antibonding orbitals at the pnictogen center) may also contribute, though to a much lesser extent.…”