Poly[diamminedi-μ₃-dicyanamido-copper(II)]

The asymmetric unit of the title polymeric mononuclear Cu^II complex, [Cu(C₂N₃)₂(NH₃)₂]_n, contains one half-mol­ecule, the complex being completed through inversion symmetry, with the Cu^II atom situated on the centre of symmetry. The coordination polyhedron around Cu^II is a Jahn–Teller-distorted [CuN₆] octa­hedron. The terminal N atoms of two dicyanamide ligands and two ammine ligands form an approximate square plane, with N—Cu—N bite angles of 89.72 (5) and 90.28 (5)°. The coordination polyhedron is completed in the axial positions by the central amide-type N atoms of two additional dicyanamide ligands, with an elongated Cu—N distance of 2.548 (1) Å. In turn, each of the four dicyanamide ligands, acting as bidentate, link the Cu^II ions into a two-dimensional polymeric structure parallel to (100). The ammine H atoms are involved in inter­molecular hydrogen bonding with the free terminal N atoms of neighbouring dicyanamide ligands, yielding a three-dimensional network.

Related literature

For bonding modes of the dicyanamide ligand, see: Burčák et al. (2004); Yang et al. (2004); van Albada et al. (2001); Potočňák et al. (2002); Zhang et al. (2004); Mohamadou et al. (2003); Batten et al. (2000); Kožíšek et al. (2007). For magnetic properties of [M(dicyanamide)₂] compounds, see: Batten & Murray (2003); Kurmoo & Kepert (1998).

Experimental

Crystal data

• [Cu(C₂N₃)₂(NH₃)₂]

• M_r = 229.72

• Monoclinic, P 2₁ /c

• a = 7.1310 (2) Å

• b = 9.6301 (2) Å

• c = 7.2162 (2) Å

• β = 113.782 (3)°

• V = 453.47 (2) ų

• Z = 2

• Mo Kα radiation

• μ = 2.38 mm⁻¹

• T = 298 K

• 0.52 × 0.32 × 0.17 mm

Data collection

• Oxford Diffraction Gemini R CCD diffractometer

• Absorption correction: analytical [CrysAlis RED (Oxford Diffraction, 2010), based on expressions derived by Clark & Reid (1995)] T_min = 0.410, T_max = 0.682

• 19836 measured reflections

• 1126 independent reflections

• 1019 reflections with I > 2σ(I)

• R_int = 0.016

Refinement

• R[F² > 2σ(F²)] = 0.017

• wR(F²) = 0.052

• S = 1.07

• 1126 reflections

• 74 parameters

• H atoms treated by a mixture of independent and constrained refinement

• Δρ_max = 0.21 e Å⁻³

• Δρ_min = −0.25 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N1—H1⋯N4^i	0.84 (2)	2.43 (2)	3.2555 (18)	165.4 (19)
N1—H2⋯N4^ii	0.89 (2)	2.34 (2)	3.2278 (18)	175.7 (17)
N1—H3⋯N4^iii	0.81 (2)	2.43 (2)	3.2073 (18)	162.1 (19)
Symmetry codes: (i) ; (ii) ; (iii) -x, -y, -z+1.

Data collection: CrysAlis CCD (Oxford Diffraction, 2010); cell refinement: CrysAlis CCD; data reduction: CrysAlis RED (Oxford Diffraction, 2010); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1998); software used to prepare material for publication: enCIFer (Allen et al., 2004).

Supporting information

S1. Comment

Among the various classes of ligands currently employed for the generation of coordination compounds, dicyanamide (dca) has been attracting a lot of attention, partly due to the discovery of interesting magnetic properties in the M(dca)₂ compounds (Batten & Murray, 2003; Kurmoo & Kepert, 1998). A particular feature of this ligand is the variability in coordination modes it can display and thus it is able to generate one- to three-dimensional networks, as well as molecular and ionic compounds, depending on its metallic centers and its organic coligands. In coordination compounds of copper, the dca anion, (N(CN)₂), exhibits a rich variety of bonding modes. It can coordinate either in a monodentate manner (Burčák et al., 2004; Yang et al., 2004;) or, more typically, in a bidentate manner [two types of binding: mainly through two nitrile N atoms (Albada et al., 2001; Potočňák et al., 2002; Zhang et al., 2004), but also through one amide and one nitrile N atom (Mohamadou et al., 2003), or even in a tridentate manner (Batten et al., 2000; Kožíšek et al., 2007). The asymmetric unit of the title compound, (I), [Cu(N(CN)₂)₂(NH₃)₂]_n, contains one-half of the molecule with the Cu^II atom situated at the centre of symmetry and is octahedrally coordinated by two ammino and two bidentate dca ligands, forming a CuN6 coordination environment (Fig.1). Two terminal N atoms of two dca units and two ammino ligands forming an approximate square plane with N—Cu—N bite angles of 89.72 (5) and 90.28 (5)°. Coordinaton polyhedron is completed in axial position by the central amide N atoms of two additional dca ligands with the Cu–N elongated distance of 2.548 (1) Å as a result of the Jahn–Teller effect. The amino H atoms are involved in intermolecular hydrogen bonding with the free terminal N atoms of neighbouring dicyanamide ligands, yielding a three-dimensional network (Fig.2).

Related literature

For bonding modes of the dicyanamide ligand, see: Burčák et al. (2004); Yang et al. (2004); van Albada et al. (2001); Potočňák et al. (2002); Zhang et al. (2004); Mohamadou et al. (2003); Batten et al. (2000); Kožíšek et al. (2007). For magnetic properties of [M(dicyanamide)₂] compounds, see: Batten & Murray (2003); Kurmoo & Kepert (1998).

S2. Experimental

A solution of Cu(SO₄)₂.5H₂O (2.0 mmol) in water (3 ml) was added to a solution of K[N(CN)₂] (4.0 mmol) in water (10 ml)and mixed with a solution of ammine (4.0 mmol) in water (10 ml). After standing for a few days, blue crystals of (I) were isolated (yield: ca 10%).

S3. Refinement

The ammine H atoms were located in a difference Fourier map and refined with a fixed isotropic displacement parameter.

Computing details

Data collection: CrysAlis CCD (Oxford Diffraction, 2010); cell refinement: CrysAlis CCD (Oxford Diffraction, 2010); data reduction: CrysAlis RED (Oxford Diffraction, 2010); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 1998); software used to prepare material for publication: enCIFer (Allen et al., 2004).

Figures

	Fig. 1. Part of the polymeric structure of (I), with the displacement ellipsoids drawn at the 50% probability level.
	Fig. 2. A packing diagram for (I) showing the hydrogen-bonding network as green dashed lines.

Poly[diamminedi-µ₃-dicyanamido-copper(II)]

Crystal data

[Cu(C2N3)2(NH3)2]	F(000) = 230
Mr = 229.72	Dx = 1.682 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 15460 reflections
a = 7.1310 (2) Å	θ = 3.7–29.3°
b = 9.6301 (2) Å	µ = 2.38 mm^−1
c = 7.2162 (2) Å	T = 298 K
β = 113.782 (3)°	Block, dark blue
V = 453.47 (2) Å^3	0.52 × 0.32 × 0.17 mm
Z = 2

Data collection

Oxford Diffraction Gemini R CCD diffractometer	1126 independent reflections
Radiation source: fine-focus sealed tube	1019 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.016
Detector resolution: 10.4340 pixels mm^-1	θmax = 28.3°, θmin = 3.7°
ω and ϕ scans	h = −9→9
Absorption correction: analytical [CrysAlis RED (Oxford Diffraction, 2010), based on expressions derived by Clark & Reid (1995)]	k = −12→12
Tmin = 0.410, Tmax = 0.682	l = −9→9
19836 measured reflections

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.017	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.052	H atoms treated by a mixture of independent and constrained refinement
S = 1.07	w = 1/[σ^2(Fo^2) + (0.0314P)^2 + 0.113P] where P = (Fo^2 + 2Fc^2)/3
1126 reflections	(Δ/σ)max < 0.001
74 parameters	Δρmax = 0.21 e Å^−3
0 restraints	Δρmin = −0.25 e Å^−3

Special details

Experimental. face-indexed (CrysAlis RED; Oxford Diffraction, 2010)

Absorption correction: CrysAlis RED, Oxford Diffraction Ltd., Version 1.171.32.8 (release 30-07-2007 CrysAlis171 .NET) (compiled Jul 30 2007,18:35:48) Analytical numeric absorption correction using a multifaceted crystal model based on expressions derived by R.C. Clark & J.S. Reid. (Clark, R. C. & Reid, J. S. (1995). Acta Cryst. A51, 887-897)

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
C1	0.12500 (18)	0.20615 (12)	0.40737 (17)	0.0314 (2)
C2	0.2567 (2)	−0.00704 (11)	0.5168 (2)	0.0313 (3)
N1	−0.26849 (18)	0.41648 (13)	0.45514 (19)	0.0362 (2)
H1	−0.351 (3)	0.472 (2)	0.371 (4)	0.054 (6)*
H2	−0.283 (3)	0.417 (2)	0.572 (3)	0.053 (5)*
H3	−0.281 (3)	0.338 (3)	0.410 (3)	0.062 (6)*
N2	0.09027 (19)	0.32110 (12)	0.42058 (18)	0.0416 (3)
N3	0.15107 (18)	0.07772 (11)	0.36879 (16)	0.0389 (3)
N4	0.3460 (2)	−0.09051 (13)	0.63406 (19)	0.0462 (3)
Cu1	0.0000	0.5000	0.5000	0.02839 (10)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0349 (5)	0.0285 (6)	0.0293 (5)	0.0008 (4)	0.0114 (4)	−0.0034 (4)
C2	0.0340 (6)	0.0271 (6)	0.0332 (6)	−0.0019 (4)	0.0140 (5)	−0.0056 (4)
N1	0.0405 (6)	0.0299 (5)	0.0365 (6)	−0.0005 (4)	0.0138 (5)	−0.0001 (5)
N2	0.0518 (7)	0.0276 (5)	0.0431 (6)	0.0054 (5)	0.0168 (5)	−0.0042 (4)
N3	0.0520 (6)	0.0267 (5)	0.0313 (5)	0.0077 (4)	0.0097 (5)	−0.0046 (4)
N4	0.0520 (7)	0.0353 (6)	0.0459 (6)	0.0033 (5)	0.0140 (5)	0.0045 (5)
Cu1	0.03572 (14)	0.01832 (13)	0.03050 (14)	0.00135 (6)	0.01271 (10)	−0.00132 (6)

Geometric parameters (Å, º)

C1—N2	1.1466 (17)	N1—H2	0.89 (2)
C1—N3	1.2975 (16)	N1—H3	0.81 (2)
C2—N4	1.1546 (18)	N2—Cu1	2.0021 (11)
C2—N3	1.3135 (17)	Cu1—N1^i	1.9793 (12)
N1—Cu1	1.9793 (12)	Cu1—N2^i	2.0021 (11)
N1—H1	0.84 (2)
N2—C1—N3	172.98 (14)	C1—N2—Cu1	163.67 (11)
N4—C2—N3	173.97 (14)	C1—N3—C2	120.18 (11)
Cu1—N1—H1	102.1 (15)	N1^i—Cu1—N1	180.00 (7)
Cu1—N1—H2	108.6 (12)	N1^i—Cu1—N2	89.72 (5)
H1—N1—H2	111 (2)	N1—Cu1—N2	90.28 (5)
Cu1—N1—H3	112.9 (15)	N1^i—Cu1—N2^i	90.28 (5)
H1—N1—H3	112 (2)	N1—Cu1—N2^i	89.72 (5)
H2—N1—H3	110.2 (19)	N2—Cu1—N2^i	180.0
N3—C1—N2—Cu1	124.8 (10)	C1—N2—Cu1—N1^i	130.8 (4)
N2—C1—N3—C2	−178.5 (11)	C1—N2—Cu1—N1	−49.2 (4)
N4—C2—N3—C1	179 (100)	C1—N2—Cu1—N2^i	24 (100)

Symmetry code: (i) −x, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N1—H1···N4^ii	0.84 (2)	2.43 (2)	3.2555 (18)	165.4 (19)
N1—H2···N4^iii	0.89 (2)	2.34 (2)	3.2278 (18)	175.7 (17)
N1—H3···N4^iv	0.81 (2)	2.43 (2)	3.2073 (18)	162.1 (19)

Symmetry codes: (ii) x−1, −y+1/2, z−1/2; (iii) −x, y+1/2, −z+3/2; (iv) −x, −y, −z+1.