Chemical bonding in silicon-carbene complexes

Area of Science:

• Organosilicon Chemistry
• Computational Chemistry
• Inorganic Chemistry

Background:

• Silicon-carbene complexes represent a novel class of compounds with unique bonding characteristics.
• Understanding their electronic structure is crucial for predicting reactivity and stability.

Purpose of the Study:

• To investigate the bonding nature in newly synthesized silicon-carbene complexes.
• To determine the primary interactions governing the silicon-carbon bond in these complexes.

Main Methods:

• Density Functional Theory (DFT) calculations at the BP86/TZ2P level.
• Energy Decomposition Analysis (EDA) to dissect bonding contributions.
• Analysis of molecular orbital energies.

Main Results:

• The bonding in silicon-carbene complexes is not accurately described by the Dewar-Chatt-Duncanson model.
• Electrostatic attraction is a key, often dominant, factor in Si-C(carbene) interactions.
• Lowered molecular orbital energies indicate stabilized carbene character.

Conclusions:

• Silicon-carbene complexes exhibit bonding distinct from typical donor-acceptor interactions.
• Electrostatic forces play a significant role in stabilizing these silicon-carbene systems.
• These complexes are best viewed as stabilized carbene entities.