Which DFT factors influence the accuracy of 1H, 13C and 195Pt NMR chemical shift predictions in organopolymetallic square-planar complexes? New scaling parameters for homo- and hetero-multimetallic compounds and their direct applications

Because of their chemical heterogeneity, stereochemical complexity and the presence of heavy atoms involving orbitals with high quantum number L, organopolymetallic complexes require considerable focus during their NMR spectral interpretation. Until now, computational NMR studies have mainly focused on mono-nuclear species; at the same time, recent literature displays that new synthetic procedures are being developed to efficiently insert two or more metals into organic scaffolds, and hence an ad hoc theoretical NMR protocol is urgently required. This study, exploiting a solid calibration set, provides a comprehensive overview of the H-1, C-13 and Pt-195 NMR prediction trends when DFT parameters are scanned. The best performing levels for H-1 (GIAO/TPSSTPSS/x2c-TZVPPallS/SUPERFINE/SMD), C-13 (GIAO/CAM-B3LYP/Jorge-TZP/SUPERFINE/CPMC) and Pt-195 (GIAO/TPSSTPSS/LANL2DZ/SUPERFINE/SMD) were employed as guidance for important NMR elucidations including both regio- and stereo-chemical features. Finally, the presented fitted scaling factors were proved to have a considerable transferibility between different solvents without re-parameterization.