Planar tetra-, penta-, hexa-, hepta-, and octacoordinate silicons: a universal structural pattern

Area of Science:

• Computational Chemistry
• Materials Science
• Quantum Chemistry

Background:

• Exploring novel structural motifs in main group chemistry is crucial for advancing materials science.
• Planar coordination in main group elements beyond boron is less understood and experimentally challenging.

Purpose of the Study:

• To present a universal structural pattern for incorporating planar silicon in boron-based clusters.
• To investigate the electronic properties and aromaticity of these novel silicon-containing boron clusters.
• To provide theoretical data for guiding future experimental validation.

Main Methods:

• Density Functional Theory (DFT) calculations were employed to optimize structures and analyze electronic properties.
• Analysis of valence electron counts and delocalized pi and sigma orbitals was performed.
• Calculation of vertical detachment energies for anionic species was conducted.

Main Results:

• A universal structural pattern was identified for planar tetra- to octacoordinate silicons in B(n)E2Si and B8Si systems.
• Optimized structures exhibit electronic characteristics analogous to small boron clusters, supporting planar silicon incorporation.
• The B(n)E2Si series are predicted to be aromatic, with calculated vertical detachment energies provided.

Conclusions:

• The discovered structural pattern offers a pathway to synthesize novel planar silicon-containing boron clusters.
• This pattern is potentially applicable to other planar main group elements like Germanium, Phosphorus, Arsenic, Aluminum, and Gallium.
• Experimental confirmation is needed to establish a new field of planar coordinate main group chemistry.