Metal Complexes with Amino Acid Amides. I. Preparations and Electronic Spectra of the Nickel(II) and Palladium(II) Complexes

Abstract
Several planar bis(amino-acid-amidato) complexes of nickel(II) and palladium(II) have been newly synthesized and characterized mainly spectroscopically. The geometrical structures of these [M(N)4]-type complexes have been determined: palladium(II) produced both cis and trans complexes with l-alanine- and l-leucine-amidate ligands, while nickel(II) did only trans forms with glycine-, l-alanine- and l-leucine-amidates. Nickel(II) also produced cationic complexes, Ni(l-alanine-amide)2SO4 and its glycine amide analogue. The circular dichroism spectra and rotatory dispersion of the complexes containing optically active amino acid amide have been measured and discussed as for the assignments of the ligand field absorption bands of the diamagnetic planar complexes. A good correspondence was observed between the circular dichroism spectra of the nickel(II) and the palladium(II) complexes.