Planar hexacoordinate sulfur and selenium.

Area of Science:

• Computational Chemistry
• Inorganic Chemistry
• Materials Science

Background:

• Achieving planar hexacoordinate atoms is a significant challenge in chemistry.
• Chalcogen elements, like sulfur and selenium, typically exhibit lower coordination numbers.

Purpose of the Study:

• To predict and characterize novel planar hexacoordinate sulfur and selenium (phS/Se) clusters.
• To investigate the structural stability and bonding nature of these unique species.

Main Methods:

• High-level quantitative electronic structure calculations.
• Born-Oppenheimer molecular dynamics simulations for stability assessment.
• Energy decomposition analysis-natural orbitals for chemical valence (EDA-NOCV) for bonding analysis.

Main Results:

• The first planar hexacoordinate sulfur and selenium clusters, X©Li6H62- (X = S, Se), were computationally predicted.
• These clusters adopt stable singlet D6h-symmetric structures with a central S/Se atom bonded to a Li6 hexagon, itself capped by hydrogen atoms.
• Bonding analysis revealed a unique electronic structure with lone pairs, delocalized sigma bonds, and multicenter ionic bonds contributing to stability.

Conclusions:

• The predicted phS/Se clusters represent a breakthrough, expanding the coordination chemistry of chalcogen elements.
• The high stability of these planar hexacoordinate structures was confirmed through dynamic simulations.
• These findings open new avenues for exploring novel planar hexacoordinate complexes in both theoretical and experimental research.