Received 25 April 2013
The title compound, Na[Cu(en)2][Cu(CN)4], where en represents ethylenediamine, NH2CH2CH2NH2, crystallizes as a salt with two distinct cations, Na+ and [CuIIen2]2+, and discrete [CuI(CN)4]3- anions. The anion geometry is tetrahedral, with angles at the copper atom ranging from 105.0 (1) to 115.4 (1)°. The Cu-C distances are in the range 1.976 (3) to 1.993 (3) Å. The divalent copper atom is coordinated by four N atoms of the two bidentate en ligands in a slightly distorted square-planar geometry. In the crystal, each sodium ion interacts with cyanide N atoms of four different anions, with Na-N distances lying in the narrow range of 2.344 (3) to 2.367 (3) Å, and an approximately tetrahedral arrangement around the sodium ions. The interacting sodium ions and [CuI(CN)4]3- anions form a three-dimensional network with channels which contain the [Cu(en)2]2+ cations. One of the chelate rings in the cation shows partial disorder between two different conformations and the C atoms were refined with occupancies in the ratio 0.817 (15):0.183 (15).
The work presented here continues studies on mixed-valence copper cyanide complexes, see: Corfield et al. (2012). Studies by others on similar complexes include Colacio et al. (2002) and Kim et al. (2005). For other results on the specific system CuI,II-CN-en, see: Williams et al. (1972) and Weiss et al. (2006). We are aware of only one other detailed crystal structure describing the discrete [Cu(CN)4]3- anion, that reported for K3Cu(CN)4 in Roof et al. (1968). For molar conductance, see: Angelici (1977).
Data collection: CAD-4 Software (Enraf-Nonius, 1994); cell refinement: CAD-4 Software; data reduction followed procedures in Corfield et al. (1973): data were averaged with a local version of SORTAV (Blessing, 1989); program(s) used to solve structure: locally modified program (Corfield, 1984); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008) and XABS2 (Parkin et al., 1995); molecular graphics: ORTEPIII (Burnett & Johnson, 1996); software used to prepare material for publication: SHELXL97.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: LH5608 ).
We are grateful to Nancy McGuire and the X-Ray Lab then at Union Carbide in Tarrytown, NY, for use of their CAD-4 diffractometer. We thank Caryn Goodwin, Linda Kuzcko, Ruth Josenhans, John Oskam, and Nicholas Della Rocco for their assistance in this work. We also acknowledge gratefully an Atlantic Richfield Foundation grant from the Research Corporation, and funding from the Alumni Association of The King's College, where the experimental work was carried out.
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