COORDINATION BEHAVIOR OF N-CARBOXYMETHYLPSEUDOEPHEDRINE - CRYSTAL-STRUCTURES OF 7-CO-ORDINATED CADMIUM(II) AND FAC-RS-OCTAHEDRAL COPPER(II)COMPLEXES

Go-ordination compounds of N-[2-hydroxy 1(R)-methyl-2(R)-phenylethyl]- N-methylglycine (N-carboxymethyl-pseudoephedrine, Hcpse) with copper(I I), cobalt(II) and cadmium(II) have been prepared and characterised. C rystal structures of copper and cadmium complexes were obtained. In th e compound [Cu(cpse)(2)]. H2O, two cpse are co-ordinated in a tridenta te mode giving place to a fac-RS-octahedral geometry. The monomeric co mpound [Cd(cpse)(2)(H2O)] has an uncommon seven-co-ordinate geometry w ith one cpse bonded in a similar arrangement to that of the copper(II) compound, with an oxygen from the carboxylate group in an apical posi tion. The second cpse molecule is co-ordinated with all three atoms in the equatorial plane, the remaining axial position of the distorted p entagonal bipyramid being occupied by a water molecule. As for the lat ter complex, the metal centre of [Cd(cpse)Cl(H2O)]. H2O . dmso (dmso = dimethyl sulfoxide) presents a distorted pentagonal-bipyramidal geome try where the apical positions are occupied by a water molecule and a chloride ion. The tridentate cpse ligand lies in the equatorial plane and the co-ordination sphere is completed by a chelating carboxylic gr oup from another cpse ligand. Each carboxylate group of cpse is bridgi ng two different cadmium atoms, forming a zigzag chain in a polymeric structure.