Reactivity of 2-Pyridinecarboxylic Esters with Cadmium(II) Halides: Study of 113Cd NMR Solid State Spectra and Crystal Structures of Hexacoordinated Complexes [CdI2(C5H4NCOOMe)2] and [CdI2(C5H4NCOOPrn)2]

The series of complexes [CdX2(C5H4NCOOR)] (X = Cl or Br; R = Me, Et, Prn or Pri) and [CdX2(C5H4NCOOR)2] (X = I; R = Me, Et, Prn, or Pri) have been obtained by the addition reaction of esters of 2-pyridinecarboxylic acid to cadmium(II) halides. X-ray crystal structures of two complexes [CdI2(C5H4NCOOR)2], R = Me (10) and R = Prn (12), have been determined. In both cases, the structure consists of discrete neutral monomeric units where the cadmium atom has a distorted octahedral coordination with CdI2N2O2 core, two halides being in cis disposition. Structural information is compared with that deduced from 113Cd CPMAS NMR experiments. Chemical shift anisotropies are discussed in terms of distortions produced in cadmium octahedra. The orientation of the principal axes of 113Cd shielding tensor is also analyzed and related to the disposition of ligands in the structures of two analyzed compounds.