Stereoinversion of tetrahedral p-block element hydrides

Area of Science:

• Computational chemistry
• Quantum chemistry
• Solid-state chemistry

Background:

• Stereochemical inversion is a fundamental process in molecular chemistry.
• Understanding inversion pathways is crucial for predicting reactivity and designing new compounds.
• Previous studies have not fully elucidated the competition between stereoinversion and other reaction channels in p-block hydrides.

Purpose of the Study:

• To investigate the potential energy surfaces of 15 tetrahedral p-block element hydrides.
• To determine if stereoinversion competes with reductive H2-elimination or hydride loss.
• To identify the pathways through which stereomutation occurs.

Main Methods:

• Multireference electronic structure calculations were employed.
• Potential energy surfaces were screened for 15 p-block element hydrides.
• The mHEAT+ protocol was utilized to revisit methane's inversion transition structure.

Main Results:

• First-time identification of stereoinversion transition structures for ammonium cation (C4v) and tetrahydridoborate anion (Cs).
• Methane's inversion activation enthalpy was found to be below its C-H bond dissociation enthalpy.
• Novel stepwise inversion pathways were discovered for silicon and phosphorus hydrides.

Conclusions:

• Stereochemical inversion is a viable reaction pathway for p-block element hydrides, competing with other reactions.
• Structure-energy relationships provide insights for designing structurally constrained compounds.
• This study offers a comprehensive understanding of stereoinversion in p-block hydrides.