Assessment of Os-187 NMR chemical shift in Os(II)-arene complexes using a new NMR-DKH basis set

The present work aims to develop a computational protocol, considering a nonrelativistic Hamiltonian with the NMR-DKH basis set, for predicting the ¹⁸⁷Os NMR chemical shifts δ¹⁸⁷Os in Os^II-arene complexes. We evaluated the role of the Os basis set (OSBS) in describing the structure and the δ¹⁸⁷Os, and the role of the DFT functional in predicting the δ¹⁸⁷Os. Thus, a total of 16 protocols at GIAO-DFT-functional/NMR-OSBS/IEF-PCM(UFF)//B3LYP/Opt-OSBS/def2-SVP/IEF-PCM(UFF) level were proposed and assessed over a training set of 37 complexes. When compared with the experimental data, the calculated results considering DFT-functional = OPBE, NMR-OSBS = NMR-DKH, and Opt-OSBS = LANL2TZ(f) showed a mean relative error (MRE) of 4.30% and a coefficient of determination (R²) of 0.969. This protocol was applied to a new set of 30 complexes (external validation set) and presented a MRE of 3.32% and R² = 0.939.