On the Quantum Chemical Nature of Lead(II) "Lone Pair"

TL;DR

This study investigates the quantum chemical nature of Lead(II) lone pairs, revealing that their structure is primarily governed by 6s and 6p electrons without significant involvement of 5d or 6d orbitals, impacting complexation behavior.

Contribution

The paper provides a detailed quantum chemical analysis showing Lead(II) lone pairs are mainly formed by 6s and 6p electrons, challenging previous assumptions about d-orbital involvement.

Findings

Lead(II) complexes are governed by 6s and 6p electrons.

No significant involvement of 5d or 6d orbitals in Lead(II) lone pairs.

The electronic structure influences the structural and dynamical properties of Lead(II) complexes.

Abstract

We discuss the quantum chemical nature of the Lead(II) valence basins, sometime called the Lead "lone pair". Using various chemical interpretation tools such as the molecular orbital analysis, Natural Bond Orbitals (NBO), Natural Population Analysis (NPA) and Electron Localization Function (ELF) topological analysis, we study a variety of Lead(II) complexes. A careful analysis of the results show that the optimal structures of the lead complexes are only govern by the 6s and 6p subshells whereas no involvement of the 5d orbitals is found. Similarly, we do not find any significant contribution of the 6d. Therefore, the Pb(II) complexation with its ligand can be explained through the interaction of the 6s2 electrons and the accepting 6p orbitals. We detail the potential structural and dynamical consequences of such electronic structure organization of the Pb (II) valence domain.