Moon D, Choi JH. Crystal structure of bis-[(oxalato-κ
2O1,
O2)(1,4,8,11-tetra-aza-cyclo-tetra-decane-κ
4N)chromium(III)] dichromate octa-hydrate from synchrotron X-ray data.
Acta Crystallogr E Crystallogr Commun 2017;
73:403-406. [PMID:
28316819 PMCID:
PMC5347064 DOI:
10.1107/s2056989017002614]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 02/14/2017] [Indexed: 11/17/2022]
Abstract
The asymmetric unit of the title compound, [Cr(C2O4)(C10H24N4)]2[Cr2O7]·8H2O (C10H24N4 = 1,4,8,11-tetra-aza-cyclo-tetra-decane, cyclam; C2O4 = oxalate, ox) contains one [Cr(ox)(cyclam)]+ cation, one half of a dichromate anion that lies about an inversion centre so that the bridging O atom is equally disordered over two positions, and four water mol-ecules. The terminal O atoms of the dichromate anion are also disordered over two positions with a refined occupancy ratio 0.586 (6):0.414 (6). The CrIII ion is coordinated by the four N atoms of the cyclam ligand and one bidentate oxalato ligand in a cis arrangement, resulting in a distorted octa-hedral geometry. The Cr-N(cyclam) bond lengths are in the range 2.069 (2)-2.086 (2) Å, while the average Cr-O(ox) bond length is 1.936 Å. The macrocyclic cyclam moiety adopts the cis-V conformation. The dichromate anion has a staggered conformation. The crystal structure is stabilized by inter-molecular hydrogen bonds involving the cyclam N-H groups and water O-H groups as donors, and the O atoms of oxalate ligand, water mol-ecules and the Cr2O72- anion as acceptors, giving rise to a three-dimensional network.
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