Accurate Calculation of Electron Paramagnetic Resonance Parameters for Molybdenum Compounds.

ABSTRACT: Paramagnetic molybdenum compounds are of great interest in inorganic chemistry and metalloenzyme catalysis. Electron paramagnetic resonance (EPR) spectroscopies that determine hyperfine coupling constants (HFCs) and g-tensor values are essential for investigating the electronic structure of these compounds, but require support from accurate quantum chemical approaches. Here, a database of Mo(V) complexes with well-defined structures and EPR parameters is presented, and optimal quantum chemical protocols for ⁹⁵Mo HFCs and g-values are investigated. It is shown that unmodified segmented all- electron relativistically contracted (SARC) all-electron basis sets can produce converged results for HFCs and g-values with the exact-2-component (X2C) Hamiltonian. The dependence of EPR parameters on the functional is studied in detail. Double-hybrid functionals and global hybrids with high exact exchange are top performers for ⁹⁵Mo HFCs, with PBE0-DH achieving the best agreement with experiment. Comparison of density functional theory (DFT)-derived HFCs with values obtained by coupled cluster theory with the domain-based local pair natural orbital approach (DLPNO-CCSD) shows that DFT remains the method of choice for the present set of compounds. Smaller differentiation among functionals is observed for g-tensors, although PBE0-DH is still a top performer and can be recommended as the most reliable approach overall for describing both valence and core properties of Mo compounds.

SUBMITTER: Drosou M 

PROVIDER: S-EPMC12640672 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature