First principles studies toward the design of silylene superbases: a density functional theory study

Area of Science:

• Organometallic Chemistry
• Computational Chemistry
• Materials Science

Background:

• Silylenes, divalent silicon compounds, are explored for their potential as superbases.
• Understanding the electronic and structural properties of silylenes is crucial for designing new chemical reagents.

Purpose of the Study:

• To design and computationally investigate novel silylene superbases.
• To evaluate their basicity, stability, and reactivity using DFT calculations.

Main Methods:

• Density Functional Theory (DFT) calculations at the B3LYP/6-311+G**//B3LYP/6-31+G* level.
• Calculation of proton affinities, HOMO-LUMO energy gaps, and singlet-triplet energy differences.
• Isodesmic reactions were used to determine silylene stabilization energy (SiSE).

Main Results:

• Designed silylene derivatives exhibit powerful neutral organic superbase properties.
• One derivative shows a gas phase proton affinity of ~310 kcal/mol and a THF proton affinity of 327.5 kcal/mol.
• Phosphazene groups enhance basicity and provide a second protonation site; monomeric forms are more stable than dimers.

Conclusions:

• Novel silylene superbases have been computationally designed with significant potential in organic chemistry.
• Their stability and reactivity can be tuned by structural modifications.
• DFT calculations provide reliable predictions for silylene properties, correlating well with experimental data for simpler analogs.