metal-organic compounds
catena-Poly[[bis(ethylenediamine)copper(II)]-μ-sulfato]
aBijvoet Center for Biomolecular Research, Crystal and Structural Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
*Correspondence e-mail: m.lutz@uu.nl
In the title compound, [Cu(SO4)(C2H8N2)2]n, the Cu, S and two O atoms lie on a mirror plane. The Cu atom is in a distorted octahedral environment and the ethylenediamine ligand is in a gauche conformation. The sulfate dianion is bridging, forming a one-dimensional chain. A two-dimensional net parallel to (001) is generated by N—H⋯O hydrogen bonding between the chains.
Related literature
For related Cu(II) ethylenediamine complexes, see: Cullen & Lingafelter (1970); Bertini et al. (1979); Healy et al. (1978); Manriquez et al. (1996); Taylor et al. (2006). A similar variation of axial Cu—O distances is found in many weakly coordinating anions such as sulfate (Castro et al., 2002), nitrate (Plater et al., 2008), perchlorate (Bernhardt et al., 2001) or triflate (Liu et al., 2007). The anisotropic mosaicity was treated according to Duisenberg (1983).
Experimental
Crystal data
|
Refinement
|
Data collection: COLLECT (Nonius, 1999); cell PEAKREF (Schreurs, 2005); data reduction: Eval15 (Schreurs et al., 2010) and SADABS (Sheldrick, 2008a); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008b); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008b); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97.
Supporting information
https://doi.org/10.1107/S160053681001737X/vm2026sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S160053681001737X/vm2026Isup2.hkl
2.04 g of copper sulfate pentahydrate (8.17 mmol) were dissolved in 150 ml of water and brought to boiling temperature. Then 2 ml of ethylenediamine (37 mmol) were added dropwise. The resulting deep blue solution was concentrated at 333 K and atmospheric pressure. In the concentrated solution, crystals appeared after 2 days of evaporation at room temperature.
An anisotropic mosaic model was used in the intensity integration with hkl = (0,0,1) as anisotropic vector (Duisenberg, 1983). Hydrogen atoms were located in difference Fourier maps. N—H hydrogen atoms were refined freely with isotropic displacement parameters. C—H hydrogen atoms were refined using a riding model with C—H = 0.99 Å and with Uiso(H) = 1.2 times Ueq(C).
Ethylenediamine (en) complexes of transition metals belong to the most studied compounds in inorganic chemistry. In the case of copper sulfate the tris(ethylenediamine) complex is known at room temperature (Cullen & Lingafelter, 1970) as well as at 120 K after a solid-solid
(Bertini et al., 1979). These crystal structures show the copper in an octahedral geometry and the sulfate is not coordinated to the metal but hydrogen bonded to the amine groups.Here, we report the
of the bis(ethylenediamine) complex of copper sulfate (I), in which the sulfate is bridging two copper centers. The compound thus forms a polymeric chain by coordination, which runs in the direction of the c axis (Fig. 1). The copper, the sulfur and two O atoms are in special positions on the crystallographic mirror plane of the orthorhombic Cmca. Bridging sulfate ions are very common in copper complexes. For example, in [Cu(en)(H2O)2]SO4, the sulfate is a bridging ligand and a one-dimensional chain is formed by coordination (Healy et al., 1978; Manriquez et al., 1996; Taylor et al., 2006).As expected, the ethylenediamine ligand is in a
conformation (Table 1) and the copper is in a distorted octahedral environment. The nitrogen atoms form the equatorial plane with Cu—N distances (2.0173 (8) and 2.0226 (8) Å), which are shorter than in the room temperature structure of the tris(ethylenediamine) complex (2.150 (2) Å). The two axial positions are occupied by oxygen atoms of sulfate anions with much longer distances than in the equatorial plane. This can be explained by the Jahn-Teller effect in Cu(II) compounds. The Cu—O distances (2.3575 (9) and 2.4673 (9) Å) also differ significantly compared to each other. Such differences are not uncommon with copper complexes of weakly coordinating anions like sulfate (Castro et al., 2002), nitrate (Plater et al., 2008), perchlorate (Bernhardt et al., 2001) or trifluoromethanesulfonate (Liu et al., 2007).The coordinated NH2 groups act as hydrogen bond donors and the non-coordinated sulfate O-atoms act as acceptors (Table 2). Two hydrogen bonds are formed within the coordination polymer via H1N and H4N. Two hydrogen bonds via H2N and H3N are between the chains resulting in a two-dimensional net in the b,c-plane (Figures 2 and 3). This two-dimensional motif is also reflected in the plate shaped crystal habitus, where the a-direction has the smallest dimension.
For related Cu(II) ethylenediamine complexes, see: Cullen & Lingafelter (1970); Bertini et al. (1979); Healy et al. (1978); Manriquez et al. (1996); Taylor et al. (2006). A similar variation of axial Cu—O distances is found in many weakly coordinating anions such as sulfate (Castro et al., 2002), nitrate (Plater et al., 2008), perchlorate (Bernhardt et al., 2001) or triflate (Liu et al., 2007). The anisotropic mosaicity was treated according to Duisenberg (1983).
Data collection: COLLECT (Nonius, 1999); cell
PEAKREF (Schreurs, 2005); data reduction: Eval15 (Schreurs et al., 2010) and SADABS (Sheldrick, 2008a); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008b); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008b); molecular graphics: PLATON (Spek, 2009); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008b).Fig. 1. : Displacement ellipsoid plot of (I), drawn at the 50% probability level. Only three units of the polymeric chain are shown. View along the b axis. Symmetry operations i: -x, 0.5 - y, z - 1/2; ii: -x, 0.5 - y, z + 1/2; iii: -x, y, z. | |
Fig. 2. : Packing of (I) in the crystal viewed along the b axis. C—H hydrogen atoms are omitted for clarity. Hydrogen bonds are drawn as dashed lines. | |
Fig. 3. : Packing of (I) in the crystal viewed along the a axis. C—H hydrogen atoms are omitted for clarity. Hydrogen bonds are drawn as dashed lines. |
[Cu(SO4)(C2H8N2)2] | F(000) = 1160 |
Mr = 279.81 | Dx = 1.917 Mg m−3 |
Orthorhombic, Cmca | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -C 2bc 2 | Cell parameters from 21936 reflections |
a = 14.4959 (3) Å | θ = 2.5–35.0° |
b = 9.63748 (8) Å | µ = 2.47 mm−1 |
c = 13.87746 (17) Å | T = 110 K |
V = 1938.73 (5) Å3 | Plate, blue |
Z = 8 | 0.36 × 0.21 × 0.06 mm |
Nonius KappaCCD diffractometer | 2204 independent reflections |
Radiation source: rotating anode | 1990 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.032 |
φ and ω scans | θmax = 35.0°, θmin = 2.8° |
Absorption correction: analytical (SADABS; Sheldrick, 2008a) | h = −23→23 |
Tmin = 0.489, Tmax = 0.910 | k = −15→15 |
29167 measured reflections | l = −20→22 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.019 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.048 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.10 | w = 1/[σ2(Fo2) + (0.0208P)2 + 2.1845P] where P = (Fo2 + 2Fc2)/3 |
2204 reflections | (Δ/σ)max = 0.001 |
86 parameters | Δρmax = 0.44 e Å−3 |
0 restraints | Δρmin = −0.56 e Å−3 |
[Cu(SO4)(C2H8N2)2] | V = 1938.73 (5) Å3 |
Mr = 279.81 | Z = 8 |
Orthorhombic, Cmca | Mo Kα radiation |
a = 14.4959 (3) Å | µ = 2.47 mm−1 |
b = 9.63748 (8) Å | T = 110 K |
c = 13.87746 (17) Å | 0.36 × 0.21 × 0.06 mm |
Nonius KappaCCD diffractometer | 2204 independent reflections |
Absorption correction: analytical (SADABS; Sheldrick, 2008a) | 1990 reflections with I > 2σ(I) |
Tmin = 0.489, Tmax = 0.910 | Rint = 0.032 |
29167 measured reflections |
R[F2 > 2σ(F2)] = 0.019 | 0 restraints |
wR(F2) = 0.048 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.10 | Δρmax = 0.44 e Å−3 |
2204 reflections | Δρmin = −0.56 e Å−3 |
86 parameters |
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
Cu1 | 0.0000 | 0.226359 (15) | 0.385553 (11) | 0.00587 (4) | |
S1 | 0.0000 | 0.24252 (3) | 0.13888 (2) | 0.00541 (5) | |
O1 | 0.0000 | 0.32265 (9) | 0.22939 (6) | 0.00932 (16) | |
O2 | 0.08343 (5) | 0.15354 (7) | 0.13383 (5) | 0.01049 (12) | |
O3 | 0.0000 | 0.34145 (9) | 0.05699 (7) | 0.00990 (16) | |
N1 | 0.09978 (5) | 0.08890 (8) | 0.35157 (6) | 0.00890 (13) | |
H1N | 0.0983 (10) | 0.0830 (15) | 0.2899 (12) | 0.018 (4)* | |
H2N | 0.0882 (13) | 0.0121 (18) | 0.3774 (10) | 0.022 (4)* | |
N2 | 0.10526 (6) | 0.35659 (8) | 0.41674 (6) | 0.00842 (12) | |
H3N | 0.0944 (12) | 0.4387 (18) | 0.3986 (11) | 0.020 (4)* | |
H4N | 0.1142 (11) | 0.3552 (15) | 0.4779 (11) | 0.016 (4)* | |
C1 | 0.18950 (6) | 0.14531 (9) | 0.38195 (7) | 0.01121 (15) | |
H1A | 0.2397 | 0.1034 | 0.3434 | 0.013* | |
H1B | 0.2007 | 0.1241 | 0.4508 | 0.013* | |
C2 | 0.18704 (7) | 0.30147 (9) | 0.36647 (7) | 0.01045 (15) | |
H2A | 0.2438 | 0.3445 | 0.3926 | 0.013* | |
H2B | 0.1833 | 0.3227 | 0.2968 | 0.013* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cu1 | 0.00700 (7) | 0.00409 (6) | 0.00652 (7) | 0.000 | 0.000 | −0.00089 (4) |
S1 | 0.00864 (12) | 0.00388 (10) | 0.00371 (11) | 0.000 | 0.000 | −0.00008 (8) |
O1 | 0.0172 (4) | 0.0071 (4) | 0.0036 (4) | 0.000 | 0.000 | −0.0017 (3) |
O2 | 0.0111 (3) | 0.0101 (3) | 0.0102 (3) | 0.0040 (2) | 0.0003 (2) | −0.0006 (2) |
O3 | 0.0192 (4) | 0.0057 (3) | 0.0048 (4) | 0.000 | 0.000 | 0.0012 (3) |
N1 | 0.0094 (3) | 0.0064 (3) | 0.0109 (3) | −0.0003 (2) | −0.0013 (3) | −0.0010 (2) |
N2 | 0.0126 (3) | 0.0064 (3) | 0.0063 (3) | −0.0012 (2) | 0.0005 (2) | −0.0004 (2) |
C1 | 0.0091 (4) | 0.0088 (3) | 0.0157 (4) | 0.0001 (3) | −0.0027 (3) | −0.0002 (3) |
C2 | 0.0103 (4) | 0.0094 (3) | 0.0116 (4) | −0.0024 (3) | 0.0012 (3) | −0.0003 (3) |
Cu1—N1i | 2.0172 (8) | N1—H1N | 0.858 (16) |
Cu1—N1 | 2.0173 (8) | N1—H2N | 0.839 (17) |
Cu1—N2i | 2.0226 (8) | N2—C2 | 1.4745 (12) |
Cu1—N2 | 2.0226 (8) | N2—H3N | 0.845 (17) |
Cu1—O1 | 2.3575 (9) | N2—H4N | 0.859 (15) |
Cu1—O3ii | 2.4673 (9) | C1—C2 | 1.5207 (13) |
S1—O1 | 1.4745 (9) | C1—H1A | 0.9900 |
S1—O3 | 1.4834 (9) | C1—H1B | 0.9900 |
S1—O2i | 1.4842 (7) | C2—H2A | 0.9900 |
S1—O2 | 1.4842 (7) | C2—H2B | 0.9900 |
N1—C1 | 1.4712 (12) | ||
N1i—Cu1—N1 | 91.62 (4) | C1—N1—H1N | 109.4 (10) |
N1i—Cu1—N2i | 85.22 (3) | Cu1—N1—H1N | 105.0 (10) |
N1—Cu1—N2i | 176.81 (3) | C1—N1—H2N | 112.3 (12) |
N1i—Cu1—N2 | 176.81 (3) | Cu1—N1—H2N | 109.6 (12) |
N1—Cu1—N2 | 85.22 (3) | H1N—N1—H2N | 111.3 (14) |
N2i—Cu1—N2 | 97.95 (4) | C2—N2—Cu1 | 106.36 (5) |
N1i—Cu1—O1 | 92.50 (3) | C2—N2—H3N | 110.2 (11) |
N1—Cu1—O1 | 92.50 (3) | Cu1—N2—H3N | 112.1 (11) |
N2i—Cu1—O1 | 87.27 (3) | C2—N2—H4N | 110.0 (10) |
N2—Cu1—O1 | 87.27 (3) | Cu1—N2—H4N | 108.4 (10) |
N1i—Cu1—O3ii | 92.95 (3) | H3N—N2—H4N | 109.7 (14) |
N1—Cu1—O3ii | 92.95 (3) | N1—C1—C2 | 107.73 (7) |
N2i—Cu1—O3ii | 87.59 (3) | N1—C1—H1A | 110.2 |
N2—Cu1—O3ii | 87.59 (3) | C2—C1—H1A | 110.2 |
O1—Cu1—O3ii | 172.18 (3) | N1—C1—H1B | 110.2 |
O1—S1—O3 | 108.42 (5) | C2—C1—H1B | 110.2 |
O1—S1—O2i | 110.05 (3) | H1A—C1—H1B | 108.5 |
O3—S1—O2i | 109.58 (3) | N2—C2—C1 | 107.97 (7) |
O1—S1—O2 | 110.05 (3) | N2—C2—H2A | 110.1 |
O3—S1—O2 | 109.59 (3) | C1—C2—H2A | 110.1 |
O2i—S1—O2 | 109.14 (6) | N2—C2—H2B | 110.1 |
S1—O1—Cu1 | 125.23 (5) | C1—C2—H2B | 110.1 |
C1—N1—Cu1 | 108.92 (5) | H2A—C2—H2B | 108.4 |
O3—S1—O1—Cu1 | 180.0 | N2—Cu1—N1—C1 | 9.25 (6) |
O2i—S1—O1—Cu1 | 60.16 (3) | O1—Cu1—N1—C1 | 96.30 (6) |
O2—S1—O1—Cu1 | −60.16 (3) | N1—Cu1—N2—C2 | 19.71 (6) |
N1i—Cu1—O1—S1 | −45.86 (2) | N2i—Cu1—N2—C2 | −159.89 (4) |
N1—Cu1—O1—S1 | 45.86 (2) | O1—Cu1—N2—C2 | −73.03 (6) |
N2i—Cu1—O1—S1 | −130.95 (2) | Cu1—N1—C1—C2 | −35.63 (9) |
N2—Cu1—O1—S1 | 130.95 (2) | Cu1—N2—C2—C1 | −44.31 (8) |
N1i—Cu1—N1—C1 | −171.12 (4) | N1—C1—C2—N2 | 53.74 (10) |
Symmetry codes: (i) −x, y, z; (ii) −x, −y+1/2, z+1/2. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1N···O2 | 0.858 (16) | 2.280 (16) | 3.0944 (11) | 158.5 (14) |
N1—H2N···O3iii | 0.839 (17) | 2.274 (17) | 3.0642 (11) | 157.1 (17) |
N2—H3N···O2iv | 0.845 (17) | 2.125 (17) | 2.9636 (10) | 171.6 (16) |
N2—H4N···O2v | 0.859 (15) | 2.210 (15) | 3.0308 (10) | 159.7 (14) |
Symmetry codes: (iii) −x, y−1/2, −z+1/2; (iv) x, y+1/2, −z+1/2; (v) x, −y+1/2, z+1/2. |
Experimental details
Crystal data | |
Chemical formula | [Cu(SO4)(C2H8N2)2] |
Mr | 279.81 |
Crystal system, space group | Orthorhombic, Cmca |
Temperature (K) | 110 |
a, b, c (Å) | 14.4959 (3), 9.63748 (8), 13.87746 (17) |
V (Å3) | 1938.73 (5) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 2.47 |
Crystal size (mm) | 0.36 × 0.21 × 0.06 |
Data collection | |
Diffractometer | Nonius KappaCCD |
Absorption correction | Analytical (SADABS; Sheldrick, 2008a) |
Tmin, Tmax | 0.489, 0.910 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 29167, 2204, 1990 |
Rint | 0.032 |
(sin θ/λ)max (Å−1) | 0.807 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.019, 0.048, 1.10 |
No. of reflections | 2204 |
No. of parameters | 86 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.44, −0.56 |
Computer programs: COLLECT (Nonius, 1999), PEAKREF (Schreurs, 2005), Eval15 (Schreurs et al., 2010) and SADABS (Sheldrick, 2008a), SHELXS97 (Sheldrick, 2008b), SHELXL97 (Sheldrick, 2008b), PLATON (Spek, 2009).
Cu1—N1 | 2.0173 (8) | Cu1—O1 | 2.3575 (9) |
Cu1—N2 | 2.0226 (8) | Cu1—O3i | 2.4673 (9) |
N1ii—Cu1—N1 | 91.62 (4) | N2—Cu1—O1 | 87.27 (3) |
N1—Cu1—N2ii | 176.81 (3) | N1—Cu1—O3i | 92.95 (3) |
N1—Cu1—N2 | 85.22 (3) | N2—Cu1—O3i | 87.59 (3) |
N2ii—Cu1—N2 | 97.95 (4) | O1—Cu1—O3i | 172.18 (3) |
N1—Cu1—O1 | 92.50 (3) | ||
N1—C1—C2—N2 | 53.74 (10) |
Symmetry codes: (i) −x, −y+1/2, z+1/2; (ii) −x, y, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1N···O2 | 0.858 (16) | 2.280 (16) | 3.0944 (11) | 158.5 (14) |
N1—H2N···O3iii | 0.839 (17) | 2.274 (17) | 3.0642 (11) | 157.1 (17) |
N2—H3N···O2iv | 0.845 (17) | 2.125 (17) | 2.9636 (10) | 171.6 (16) |
N2—H4N···O2v | 0.859 (15) | 2.210 (15) | 3.0308 (10) | 159.7 (14) |
Symmetry codes: (iii) −x, y−1/2, −z+1/2; (iv) x, y+1/2, −z+1/2; (v) x, −y+1/2, z+1/2. |
References
Bernhardt, P. V., Moore, E. G. & Riley, M. J. (2001). Inorg. Chem. 40, 5799–5805. Web of Science CSD CrossRef PubMed CAS Google Scholar
Bertini, I., Dapporto, P., Gatteschi, D. & Scozzafava, A. (1979). J. Chem. Soc. Dalton Trans. pp. 1409–1414. CSD CrossRef Web of Science Google Scholar
Castro, J., Pérez Lourido, P., Sousa-Pedrares, A., Labisbal, E., Carabel, M. & García-Vázquez, J. A. (2002). Acta Cryst. C58, m65–m67. Web of Science CSD CrossRef CAS IUCr Journals Google Scholar
Cullen, D. L. & Lingafelter, E. C. (1970). Inorg. Chem. 9, 1858–1864. CSD CrossRef CAS Web of Science Google Scholar
Duisenberg, A. J. M. (1983). Acta Cryst. A39, 211–216. CrossRef CAS IUCr Journals Google Scholar
Healy, P. C., Kennard, C. H. L., Smith, G. & White, A. H. (1978). Cryst. Struct. Commun. 7, 565–570. CAS Google Scholar
Liu, Z.-M., Liu, Y., Zheng, S.-R., Yu, Z.-Q., Pan, M. & Su, C.-Y. (2007). Inorg. Chem. 46, 5814–5816. Web of Science CSD CrossRef PubMed CAS Google Scholar
Manriquez, V., Campos-Vallette, M., Lara, N., Gonzalez-Tejeda, N., Wittke, O., Diaz, G., Diez, S., Munoz, R. & Kriskovic, L. (1996). J. Chem. Crystallogr. 26, 15–22. CSD CrossRef CAS Web of Science Google Scholar
Nonius (1999). COLLECT. Nonius BV, Delft, The Netherlands. Google Scholar
Plater, M. J., Gelbrich, T., Hursthouse, M. B. & De Silva, B. M. (2008). CrystEngComm, 10, 125–130. Web of Science CSD CrossRef CAS Google Scholar
Schreurs, A. M. M. (2005). PEAKREF. Utrecht University, The Netherlands. Google Scholar
Schreurs, A. M. M., Xian, X. & Kroon-Batenburg, L. M. J. (2010). J. Appl. Cryst. 43, 70–82. Web of Science CrossRef CAS IUCr Journals Google Scholar
Sheldrick, G. M. (2008a). SADABS. University of Göttingen, Germany. Google Scholar
Sheldrick, G. M. (2008b). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Spek, A. L. (2009). Acta Cryst. D65, 148–155. Web of Science CrossRef CAS IUCr Journals Google Scholar
Taylor, M. K., Stevenson, D. E., Berlouis, L. E. A., Kennedy, A. R. & Reglinski, J. (2006). J. Inorg. Biochem. 100, 250–259. Web of Science CSD CrossRef PubMed CAS Google Scholar
This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
Ethylenediamine (en) complexes of transition metals belong to the most studied compounds in inorganic chemistry. In the case of copper sulfate the tris(ethylenediamine) complex is known at room temperature (Cullen & Lingafelter, 1970) as well as at 120 K after a solid-solid phase transition (Bertini et al., 1979). These crystal structures show the copper in an octahedral geometry and the sulfate is not coordinated to the metal but hydrogen bonded to the amine groups.
Here, we report the crystal structure of the bis(ethylenediamine) complex of copper sulfate (I), in which the sulfate is bridging two copper centers. The compound thus forms a polymeric chain by coordination, which runs in the direction of the c axis (Fig. 1). The copper, the sulfur and two O atoms are in special positions on the crystallographic mirror plane of the orthorhombic space group Cmca. Bridging sulfate ions are very common in copper complexes. For example, in [Cu(en)(H2O)2]SO4, the sulfate is a bridging ligand and a one-dimensional chain is formed by coordination (Healy et al., 1978; Manriquez et al., 1996; Taylor et al., 2006).
As expected, the ethylenediamine ligand is in a gauche conformation (Table 1) and the copper is in a distorted octahedral environment. The nitrogen atoms form the equatorial plane with Cu—N distances (2.0173 (8) and 2.0226 (8) Å), which are shorter than in the room temperature structure of the tris(ethylenediamine) complex (2.150 (2) Å). The two axial positions are occupied by oxygen atoms of sulfate anions with much longer distances than in the equatorial plane. This can be explained by the Jahn-Teller effect in Cu(II) compounds. The Cu—O distances (2.3575 (9) and 2.4673 (9) Å) also differ significantly compared to each other. Such differences are not uncommon with copper complexes of weakly coordinating anions like sulfate (Castro et al., 2002), nitrate (Plater et al., 2008), perchlorate (Bernhardt et al., 2001) or trifluoromethanesulfonate (Liu et al., 2007).
The coordinated NH2 groups act as hydrogen bond donors and the non-coordinated sulfate O-atoms act as acceptors (Table 2). Two hydrogen bonds are formed within the coordination polymer via H1N and H4N. Two hydrogen bonds via H2N and H3N are between the chains resulting in a two-dimensional net in the b,c-plane (Figures 2 and 3). This two-dimensional motif is also reflected in the plate shaped crystal habitus, where the a-direction has the smallest dimension.