Quantum chemical calculations of cadmium chemical shifts in inorganic complexes

This study reports a systematic approach of ab initio calculations of Cd-113 chemical shifts to understand the coordination chemistry of cadmium complexes. Cadmium-113 chemical shifts were calculated using Hartree-Fock (HF) and density functional theoretical (DFT) methods for cadmium complexes, dimethylcadmium (CdMe2), diethylcadmium (CdEt2), methylethylcadmium (CdMeEt), cadmium nitrate tetrahydrate [Cd(NO3)(2). 4H(2)O], and cadmium acetate dihydrate [Cd(OAc)(2)-2H(2)O]. Theoretical and experimental chemical shift values are compared in order to determine the effectiveness of theoretical calculations in determining cadmium chemical shifts. We also determined the magnitude of the principal elements of the Cd-113 CSA tensor values for hydrated cadmium nitrate and cadmium acetate. The effect of different cadmium basis sets such as polarized double-xi split valence, 3-21G, and uncontracted Sadlej on chemical shift values was also evaluated. The density functional calculations were found to match the experimental chemical shift values considerably better than the Hartree-Fock calculations. Further, the agreement between the theoretical and experimental values significantly improved with the inclusion of a sufficient number of water molecules. Cadmium-113 chemical shifts of several cadmium complexes with coordination number six were analyzed in order to examine the efficacy of the ab initio calculations. Theoretical results suggest that the Double-Zeta Valence Potential (DZVP) and Sadlej basis sets are better than the 3-21G basis set. Our calculations also show that ab initio calculations identify the coordination number of cadmium complexes.