NMR shielding and spin–rotation constants in XCO (X = Ni, Pd, Pt) molecules

Abstract

Ab initio nonrelativistic and four-component relativistic DFT (density functional theory) methods are combined to study the spin–rotation and absolute nuclear magnetic resonance (NMR) shielding constants of group 10 transition metal monocarbonyls. Good agreement is obtained between the calculated and available experimental data for the spin–rotation constants and shielding spans for PdCO and PtCO. These data allow us to determine accurate absolute chemical shielding constants for all the nuclei, as well as for the unknown spin–rotation constants. We compare the four-component shielding constants with those obtained from the spin–orbit zeroth-order regular approximation, together with an assessment of the performance of different basis sets. For the first time, relativistically optimised basis sets for the heavy atoms used in the four-component calculations are shown to give converged results for both magnetic properties studied.