Electric-field-induced modulation of the structural and chemical properties of phenylsilane: a theoretical investigation.

CONTEXT: Phenylsilane is an organosilicon molecule containing a silyl group attached to a benzene ring and is widely used as a hydrogen source in organic transformations such as the Mukaiyama hydration reaction. Understanding how external electric fields influence its structural and spectroscopic properties is important for clarifying field-induced molecular behavior. In this work, the effects of external electric fields on the C-C and Si-C bond lengths, total energy, infrared (IR) spectrum, Raman spectrum, UV-vis absorption spectrum, and bond dissociation energy of phenylsilane are investigated. The results show that increasing the electric field strength induces redshifts in several vibrational absorption peaks, including a shift of up to 250 cm - 1 for the Si-H vibrational mode, and leads to the appearance of new spectral features. At the maximum applied field strength, the Si-C bond length decreased from 1.882 to 1.842 Å, while the HOMO-LUMO gap decreased from 5.41 to 3.87 eV. In addition, several Raman peaks become more distinct with increasing electric field intensity. The bond length, total energy, UV-vis absorption characteristics, and the bond dissociation energy also exhibit systematic changes under different electric field strengths.

METHODS

All calculations were performed using density functional theory (DFT) at the B3LYP/6-31+G(d) level of theory. Geometry optimizations and vibrational frequency analyses were carried out under different external electric field strengths. Infrared and Raman spectra as well as UV-vis absorption spectra were obtained based on the optimized molecular structures. All quantum chemical calculations were performed using the Gaussian 16W software package.