
Chemical Science, Journal Year: 2024, Volume and Issue: 15(48), P. 20189 - 20204
Published: Jan. 1, 2024
Accurate prediction of spin-state energetics for transition metal (TM) complexes is a compelling problem in applied quantum chemistry, with enormous implications modeling catalytic reaction mechanisms and computational discovery materials. Computed are strongly method-dependent credible reference data scarce, making it difficult to conduct conclusive studies open-shell TM systems. Here, we present novel benchmark set first-row energetics, which derived from experimental 17 containing FeII, FeIII, CoII, CoIII, MnII, NiII chemically diverse ligands. The estimates adiabatic or vertical splittings, obtained spin crossover enthalpies energies spin-forbidden absorption bands, suitably back-corrected the vibrational environmental effects, employed as values benchmarking density functional theory (DFT) wave function methods. results demonstrate high accuracy coupled-cluster CCSD(T) method, features mean absolute error (MAE) 1.5 kcal mol-1 maximum -3.5 mol-1, outperforms all tested multireference methods: CASPT2, MRCI+Q, CASPT2/CC CASPT2+δMRCI. Switching Hartree-Fock Kohn-Sham orbitals not found consistently improve accuracy. best performing DFT methods double-hybrids (PWPB95-D3(BJ), B2PLYP-D3(BJ)) MAEs below 3 errors within 6 whereas so far recommended states (e.g., B3LYP*-D3(BJ) TPSSh-D3(BJ)) perform much worse 5-7 beyond 10 mol-1. This work first such extensive study chemistry use data. relevant proper choice characterize systems catalysis (bio)inorganic may also stimulate new developments quantum-chemical machine learning approaches.
Language: Английский