Crystal structure of bis-[ trans-di-chlorido-bis(propane-1,3-di-amine-κ2N, N')chromium(III)] dichromate from synchrotron data

Dohyun Moon; Keon Sang Ryoo; Jong-Ha Choi

doi:10.1107/S2056989016012755

Crystal structure of bis-[ trans-di-chlorido-bis(propane-1,3-di-amine-κ²N, N')chromium(III)] dichromate from synchrotron data

Acta Crystallogr E Crystallogr Commun. 2016 Aug 12;72(Pt 9):1293-1296. doi: 10.1107/S2056989016012755. eCollection 2016 Sep 1.

Authors

Dohyun Moon¹, Keon Sang Ryoo², Jong-Ha Choi²

Affiliations

¹ Pohang Accelerator Laboratory, POSTECH, Pohang 37673, Republic of Korea.
² Department of Chemistry, Andong National University, Andong 36729, Republic of Korea.

Abstract

The structure of the title compound, [CrCl₂(tn)₂]₂[Cr₂O₇] (tn = propane-1,3-di-amine; C₃H₁₀N₂), has been determined from synchrotron data. The asymmetric unit contains one Cr^III complex cation and half a [Cr₂O₇]^2- anion. In the complex cation, the Cr^III ion is coordinated by the four N atoms of two propane-1,3-di-amine (tn) ligands in the equatorial plane and by two Cl atoms in a trans configuration, displaying a distorted octa-hedral coordination sphere. The two six-membered rings in the complex cation have an anti chair-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 inter-molecular hydrogen bonds involving the NH₂ groups of the tn ligands as donors and the O atoms of the [Cr₂O₇]^2- anion and chlorido ligands as acceptors.

Keywords: chloride ligand; chromium(III) complex; crystal structure; dichromate anion; hydrogen bonding; propane-1,3-diamine; synchrotron radiation; trans–anti conformation.