CO-59 NMR SPECTROSCOPIC CHIRAL DISCRIMINATION OF [CO(EN)(3)](3+) ENANTIOMERS IN IONIC INTERACTING SYSTEMS

Formation of diastereomers of Delta- and Lambda-[Co(en)(3)](3+) was in vestigated in aqueous chiral-electrolyte solutions using (59)CoNMR spe ctroscopy. The chiral electrolytes used were alkali salts for L- and D -tartrates, bis(mu-(-)(589)-tartrato)diantimonate(III), N-dodecanoyl-L -(and D-)alaninate, N-dodecanoyl-L-threoninate, and N-hexadecanoyl-L-p rolinate. The (59)CoNMR parameters for the [Co(en)(3)](3+) group were different between the enantiomers in most cases. The NMR parameters us ed for chiral discrimination were chemical shifts (in simple electroly te and micellar solutions), relaxation rates (in simple electrolyte an d micellar solutions), peak areas (in micellar solutions), and quadrup ole splittings (in liquid crystalline solutions). The larger values of the relaxation rates suggest stronger interactions. On the other hand , the magnitude of the chemical shift change was not simply related to the extent of the interactions. For a chemical shift, the contributio n of a geometrical factor seems to be dominant in systems having local anisotropy in the interaction.