Is the protactinium(V) mono-oxo bond weaker than what we thought?

TL;DR

This study uses advanced quantum mechanical calculations to show that the protactinium(V) mono-oxo bond is longer and weaker than previously thought, revealing its sensitivity to complexation and challenging earlier assumptions.

Contribution

The paper provides the first robust quantum mechanical analysis of the Pa-Ooxo bond, showing it is longer and more sensitive to complexation than previously reported.

Findings

Protactinium(V) mono-oxo bond is longer than earlier reports.

Pa-Ooxo bond is more sensitive to complexation than U-Oyl bonds.

Quantum calculations support a reevaluation of bond strength and nature.

Abstract

The bond distance is the simplest and most obvious indicator of the nature of a given chemical bond. However, for rare chemistry, it may happen that it is not yet firmly established. In this communication, we will show that the formally-triple protactinium(V) mono-oxo bond is predicted longer than what was previously reported in the solid state and in solution, based on robust quantum mechanical calculations, supported by an extensive methodological study. Furthermore, additional calculations are used to demonstrate that the Pa-Ooxo bond of interest is more sensitive to complexation than the supposedly analogous U-Oyl ones, not only in terms of bond distance but also of finer bond descriptors associated with the effective bond multiplicity.