Crystal structure of bis[trans-dichloridobis(propane-1,3-diamine-κ2N,N′)chromium(III)] dichromate from synchrotron data

Abstract

The structure of the title compound, [CrCl2(tn)2]2[Cr2O7] (tn = propane-1,3-diamine; C3H10N2), has been determined from synchrotron data. The asymmetric unit contains one CrIIIcomplex cation and half a [Cr2O7]2−anion. In the complex cation, the CrIIIion is coordinated by the four N atoms of two propane-1,3-diamine (tn) ligands in the equatorial plane and by two Cl atoms in atransconfiguration, displaying a distorted octahedral coordination sphere. The two six-membered rings in the complex cation have anantichair–chair conformation with respect to each other. The mean Cr—N(tn) and Cr—Cl bond lengths are 2.09 (1) and 2.320 (2) Å, respectively. The slightly bent dichromate anion is disordered over two sets of sites (occupancy ratio = 0.7:0.3) and has a staggered conformation. The crystal structure is stabilized by intermolecular hydrogen bonds involving the NH2groups of the tn ligands as donors and the O atoms of the [Cr2O7]2−anion and chlorido ligands as acceptors.