Structural characterization and DFT study of bis-{(S)-2-[(2-hy-droxy-benz-yl)amino]-3-(4-hy-droxy-phen-yl)propano-ato-κ2N,O}(1,10-phenanthroline-κ2N,N')cadmium(II) tetra-hydrate.

In the title compound, [Cd(C16H16O3)2(C12H8N2)]·4H2O, the Cd ion lies on a twofold rotation axis and is chelated by two monodeprotonated residues of the l-tyrosine-derived ligand (S)-2-[(2-hy-droxy-benz-yl)amino]-3-(4-hy-droxy-phen-yl)propanoic acid (L) in a κ2N,O amino acid chelating mode, exhibiting an (N,N')-trans disposition, and by 1,10-phenanthroline in a κ2N,N' mode. The latter ligand is also located about the twofold rotation axis that bisects the central six-members ring. The phenolic groups remain protonated and non-coordinating and take part as acceptors in the intra-molecular hydrogen bonds with the amino groups of the acido ligands. The Cd ion is six-coordinated in a distorted octa-hedral environment. In the crystal, O-H⋯O hydrogen bonds result in the formation of three-dimensional network structures. The title complex has also been characterized by IR and 1H NMR spectroscopy and DFT studies. The crystal studied was refined as an inversion twin.