Crystal structure of bis[(S)-2-(2-hydroxybenzylamino)-4-methylpentanoato-kappa N-2,O-1](1,10-phenanthroline-kappa N-2,N ') cadmium dihydrate

The asymmetric unit of the mononuclear mixed-ligand title complex, [Cd(C13H18NO3)(2)(C12H8N2)]center dot 2H(2)O, contains two crystallographically independent molecules that differ insignificantly in their geometrical parameters. In both, the Cd-II cation lies on a twofold rotation axis and is coordinated in a distorted octahedral fashion to two monodeprotonated residues of the l-leucine-derived ligand (S)-2-(2-hydroxybenzylamino)-4-methylpentanoic acid (L), as well as to a 1,10-phenanthroline ligand in a kappa N-2,N' mode. The former coordinate in an N, O-chelating mode, exhibiting a trans-N,N' mutual disposition. The phenolic oxygen donor groups remain protonated and do not coordinate to the cation but take part in intra-and intermolecular hydrogen bonds. In the crystal, O-H center dot center dot center dot O hydrogen bonding results in the formation of a three-dimensional network structure. The contribution to the electron density of two disordered water molecules was removed with the SQUEEZE procedure in PLATON [Spek (2015). Acta Cryst. C71, 9-18]. The studied crystal was refined as a two-component inversion twin. The title complex was also characterized by IR and H-1 NMR spectroscopic methods.