NMR-DKH basis set analysis for calculation of 1j(195pt15n) in platinum(ii) complexes

Abstract

The Nuclear Magnetic Resonance is a widely used technique and plays a key role in many different areas, especially in elucidation of reaction mechanisms and designing of new drugs. In this context, the use of Quantum Chemistry methods is an important tool in NMR study. However, theoretical calculations of NMR parameters are, most of the times, expensive and imprecise. Therefore, one of the greatest challenges in Computational Chemistry is developing protocols with low computational cost that yield satisfactory results. In this work, the 1 J(195Pt15N) coupling constant was studied in Pt(II) complexes in order to develop a computational protocol for the calculation of the constant with affordable cost and satisfactory results using the all-electron relativistic basis set NMR-DKH, previously proposed for calculation of 195Pt chemical shift. Several topics were tested and analyzed in order to develop the protocol, such as DFT functionals and modifications to the basis set. The final computational protocol for predicting the 1 J(195Pt15N) coupling constant in Pt(II) complexes included a working set of 82 coupling constants for 57 Pt(II) complexes. Furthermore, it was applied for a testing set of 16 coupling constants in 14 Pt(II) complexes. The protocol was based on nonrelativistic calculations at PBEPBE/NMR-DKH level. The MAD was 36 Hz corresponding to the MRD of 10.4%, considering all 98 coupling constants for 71 Pt(II) complexes.