Crystal structure of bis[bis(1,4,7-triazacyclononane-κ3 N,N′,N′′)chromium(III)] tris(tetrachloridozincate) monohydrate from synchrotron X-ray data

Abstract

The structure of the title compound, [Cr(tacn)2]2[ZnCl4]3·H2O (tacn is 1,4,7-triazacyclononane; C6H15N3), has been determined from synchrotron X-ray data. Each CrIII cation is coordinated by the six N atoms from the two tacn ligands, displaying a distorted octahedral geometry. Three distorted tetrahedral [ZnCl4]2− anions and one lattice water molecule lie outside this coordination sphere. The Cr—N bond lengths are in the range 2.0621 (11) to 2.0851 (12) Å, while the mean inner N—Cr—N bond angle is 82.51 (5)°. The crystal packing is stabilized by hydrogen-bonding interactions with the N—H groups of the tacn ligands and the water O—H groups acting as donors, and the O atoms of the water molecules and Cl atoms of the [ZnCl4]2− anions as acceptors. Overall these contacts lead to the formation of a three-dimensional network.