SOLID-STATE CD-113 NMR-STUDIES ON CADMIUM COMPLEXES WITH GLYCINE, L-ALANINE, AND L-CYSTEINE

Solid-state Cd-113 NMR spectra have been recorded for bis(glycinato)cadmium(II) hydrate, bis(L-alaninato)cadmium(II) trihydrate, and a 1:2 complex of cadmium and L-cysteine; the principal components of the Cd-113 shielding tensor have been determined. The spectra show useful additional fine structure due to dipolar coupling (both direct and indirect) between Cd-113 and N-14, which allows the number of nitrogens bonded to the cadmium center to be determined directly. In the L-alaninate complex, two cadmium resonances are observed which are rationalized as being due to the presence of diastereoisomers within the powdered sample. The L-Cysteine complex shows no N-14 coupling, indicating that any Cd-113-N-14 interactions are weaker than in the other two complexes. An improved X-ray single-crystal structure of the glycinate complex is also reported.