Hg(II)⋅d⁸[M] Interactions: Are they Metallophilic Interactions or Spodium Bonds?

Abstract

Some literature reports have shown the existence of short Hg(II)···d8[M] (M = Pd, Pt) contacts between linear Hg(II) and square planar d8[M] complexes that have been defined as heterometallophilic interactions. Linear L–Hg(II)–L complexes exhibit a π‐hole or positive belt of electrostatic potential at the Hg atom, while late transition metals can serve as effective electron donors through their filled dz2 orbitals. This study provides compelling evidence that Hg(II)···d8[M] interactions should be more appropriately termed Spodium bonds.

Exploring Unconventional σ‐Hole Interactions: Computational Insights into the Interaction of XeO3 with Non‐Aromatic Coordinating Solvents

“…The localized region of positive electrostatic potential, which is positioned on a σ* orbital on the extension of a covalent bond between the recipient atom bound to an electron‐withdrawing atom/group, also known as a sigma hole, gives rise to the NCIs (Figure 1, left) [15] . These include halogen, chalcogen, pnictogen, tetrel, icosagen (or triel), and, more recently, spondium, regium, and aerogen bonds [16–25] …”