A density functional theory study of the zero-field splitting in high-spin nitrenes

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Spectroscopy

Background:

• High-spin nitrenes are crucial intermediates in various chemical reactions.
• Accurate prediction of zero-field splittings (ZFSs) is essential for understanding their electronic structure and reactivity.
• Existing theoretical methods for ZFS prediction have varying degrees of accuracy.

Purpose of the Study:

• To evaluate the performance of different density functional theory (DFT) approaches for predicting ZFSs in high-spin nitrenes.
• To identify the most accurate DFT methods and basis sets for ZFS calculations.
• To analyze the contributions of spin-spin (SS) and spin-orbit coupling (SOC) interactions to ZFS parameters.

Main Methods:

• Systematic evaluation of DFT methods for ZFS prediction.
• Comparison of unrestricted Kohn-Sham and Pederson-Khanna approaches.
• Utilizing PBE density functional with DZ, EPR-II, and TZV basis sets.
• Analysis of SS and SOC contributions to ZFS parameters.

Main Results:

• Unrestricted Kohn-Sham and Pederson-Khanna approaches show high success for SS and SOC contributions, respectively.
• PBE functional with DZ, EPR-II, and TZV basis sets yields predictions within 10% accuracy.
• SOC contribution is small for light-atom nitrenes but significant for E value in heavy-atom nitrenes.
• Semiempirical one-center spin-spin interaction model accurately predicts ZFS for first-row atom nitrenes.

Conclusions:

• DFT, particularly with the PBE functional and specific basis sets, is a reliable tool for ZFS prediction in high-spin nitrenes.
• Understanding the interplay of SS and SOC interactions is crucial for accurate ZFS calculations, especially in heavier molecules.
• The findings provide a robust theoretical framework for studying nitrene systems.