METAL-COMPLEXES OF BIOLOGICALLY IMPORTANT LIGANDS .68. ORGANOMETALLIC ASPARAGINATO COBALT COMPLEXES AS LIGANDS FOR ALKALINE IONS

The trischelate complexes of the dianion of aspartic acid and beta-methylaspartic acid (eta5-C5Me5)Co[O2CC(H)(NH2)C(H)(R)CO2] (R = H, Me) form adducts with alkali iodides MI (M = Li, Na, K). The polymeric structure of (eta5-C5Me5)Co(L-asp.-2H+)KI (1c) was determined by X-ray diffraction. In the crystal of 1c the potassium ions are surrounded by five oxygen atoms of the carboxylate groups whereby two oxygen atoms form bridges between two K+ ions. Similarly, trischelate complexes 4 and 5 have been obtained from (eta5-C5Me5)Co(CO)I2 and 2,3-diaminopropionic, 2,4-diaminobutyric acid, and asparagine, respectively.