Crystal structure of bis[(S)-2-(2-hydroxybenzylamino)-4-methylpentanoato-κ2 N,O 1](1,10-phenanthroline-κ2 N,N′)cadmium dihydrate

Abstract

The asymmetric unit of the mononuclear mixed-ligand title complex, [Cd(C13H18NO3)2(C12H8N2)]·2H2O, contains two crystallographically independent molecules that differ insignificantly in their geometrical parameters. In both, the CdII 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 κ2 N,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...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 1H NMR spectroscopic methods.