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Acta Cryst. (2008). E64, m53    [ doi:10.1107/S1600536807063015 ]

Poly[bis([mu]2-formato-[kappa]2O:O')(quinoxaline-[kappa]N)copper(II)]

L. Sieron

Abstract top

In the polymeric title copper(II) compound, [Cu(CHO2)2(C8H6N2)]n, both formato ligands are O-bidentate anions and act as bridging ligands, creating a planar polymeric arrangement. The slightly distorted square-pyramidal coordination around CuII comprises four O atoms from two different formate anions as the base and a quinoxaline molecule in the apical position.

Comment top

The structure determination of the title compound was undertaken as a continuation of earlier studies of copper(II) complexes with formic acid (Sieroń, 2003; 2007). A fragment of the title compound structure is shown in Fig. 1.

The CuII atom has a square-pyramidal environment. The four short equatorial Cu–O bonds, that range from 1.9489 (13) to 1.9605 (11) Å, are formed by the formate anions. The long Cu–N axial bond of 2.515 (2) Å to quinoxaline molecule completes the five coordination geometry around Cu. The degree of trigonality τ = 0.092 [τ is defined by Addison et al. (1984); for the regular square-pyramidal (SQP) structure, the trigonality parameter is 0, and for the trigonal-bipyramidal (TBP) structure, it increases to 1] indicates a slightly distorted SQP coordination of the Cu atom.

The O—C distances in both formate groups are approximately equal and range from 1.238 (2) to 1.250 (2) Å, indicating the distinct delocalization of their π electrons (Borthwick, 1980). All the formate anions coordinate in a bidentate anti-anti fashion, to result in a two-dimensional framework parralel to (101) plane (Fig. 2). The quinoxaline rings engage in π-π stacking interactions, with distances between ring centroids of 3.6704 (12) Å, and these serve to connect polymeric planes into three-dimensional network.

The closest Cu···Cu distance of 5.6164 (3) Å, corresponds aproximately to half the length of the b axis. The second-shortest Cu···Cu distance is 5.7924 (4) Å, which is half the length of the diagonal of the ac plane.

Related literature top

For related literature, see: Addison et al. (1984); Borthwick (1980); Sieroń (2003, 2007).

Experimental top

The title complex was prepared by dissolving cupric formate [2 mmol, Cu(HCOO)2.2H2O] in 50 ml of water with quinoxaline (2 mmol, C8H6N2). After heating to boiling, the formic acid was added dropwise to clear the solution. The solution was filtered and allowed to cool. After few days, green crystals were obtained.

Refinement top

All H atoms were initially located in a difference Fourier synthesis, but were positioned with idealized geometry, with C–H = 0.93 Å, and Uiso(H) = 1.2Ueq(C), and refined using a riding model.

Computing details top

Data collection: CrysAlis CCD (Oxford Diffraction, 2006); cell refinement: CrysAlis RED (Oxford Diffraction, 2006); data reduction: CrysAlis RED (Oxford Diffraction, 2006); program(s) used to solve structure: SHELXTL (Sheldrick, 2003); program(s) used to refine structure: SHELXTL (Sheldrick, 2003); molecular graphics: SHELXTL (Sheldrick, 2003) and Mercury (Macrae et al., 2006); software used to prepare material for publication: PLATON (Spek, 2003).

Figures top
[Figure 1] Fig. 1. A view of a fragment of the title compound showing 50% probability displacement ellipsoids. H atoms are shown as spheres of arbitrary radius [symmetry codes: (i) -x + 3/2, y - 1/2, -z + 1/2; (ii) x - 1/2, -y + 3/2, z - 1/2].
[Figure 2] Fig. 2. The packing diagram showing two-dimensional polymeric framework parralel to (101) plane.
(I) top
Crystal data top
[Cu(CHO2)2(C8H6N2)]F000 = 572
Mr = 283.73Dx = 1.819 Mg m−3
Monoclinic, P21/nMo Kα radiation
λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 7748 reflections
a = 9.5648 (3) Åθ = 2.8–32.3º
b = 11.1913 (3) ŵ = 2.11 mm−1
c = 10.1910 (4) ÅT = 291 K
β = 108.284 (3)ºPrism, green
V = 1035.80 (6) Å30.30 × 0.30 × 0.08 mm
Z = 4
Data collection top
KUMA KM4CCD diffractometer2378 independent reflections
Monochromator: graphite2267 reflections with I > 2σ(I)
Detector resolution: 8.2356 pixels mm-1Rint = 0.017
T = 291 Kθmax = 27.5º
ω scansθmin = 3.1º
Absorption correction: multi-scan
(CrysAlis RED; Oxford Diffraction,2006)		h = −12→12
Tmin = 0.578, Tmax = 0.843k = −14→14
12535 measured reflectionsl = −13→13
Refinement top
Refinement on F2Hydrogen site location: difference Fourier map
Least-squares matrix: fullH-atom parameters constrained
R[F2 > 2σ(F2)] = 0.027  w = 1/[σ2(Fo2) + (0.0359P)2 + 0.4837P]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.070(Δ/σ)max = 0.001
S = 1.14Δρmax = 0.35 e Å−3
2378 reflectionsΔρmin = −0.60 e Å−3
155 parametersExtinction correction: shelxl, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.0054 (8)
Secondary atom site location: structure-invariant direct methods
Crystal data top
[Cu(CHO2)2(C8H6N2)]V = 1035.80 (6) Å3
Mr = 283.73Z = 4
Monoclinic, P21/nMo Kα
a = 9.5648 (3) ŵ = 2.11 mm−1
b = 11.1913 (3) ÅT = 291 K
c = 10.1910 (4) Å0.30 × 0.30 × 0.08 mm
β = 108.284 (3)º
Data collection top
KUMA KM4CCD diffractometer2378 independent reflections
Absorption correction: multi-scan
(CrysAlis RED; Oxford Diffraction,2006)		2267 reflections with I > 2σ(I)
Tmin = 0.578, Tmax = 0.843Rint = 0.017
12535 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.027155 parameters
wR(F2) = 0.070H-atom parameters constrained
S = 1.14Δρmax = 0.35 e Å−3
2378 reflectionsΔρmin = −0.60 e Å−3
Special details top

Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell e.s.d.'s are taken into account in the estimation of distances, angles and torsion angles

Refinement. Refinement on F2 for ALL reflections except those flagged by the user for potential systematic errors. Weighted R-factors wR and all goodnesses of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The observed criterion of F2 > σ(F2) is used only for calculating -R-factor-obs 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 (Å2) top
xyzUiso*/Ueq
Cu10.72396 (2)0.74628 (2)0.24693 (2)0.0231 (1)
O10.75356 (15)0.89959 (10)0.34492 (12)0.0276 (4)
O20.88757 (15)0.68234 (11)0.39838 (14)0.0349 (4)
O30.78057 (14)1.09526 (10)0.35166 (12)0.0257 (3)
O41.05990 (14)0.68686 (11)0.59961 (12)0.0275 (3)
N10.55057 (18)0.68333 (15)0.37545 (17)0.0316 (5)
N20.3759 (2)0.66292 (17)0.55363 (17)0.0376 (6)
C10.75006 (19)0.99809 (14)0.28872 (19)0.0240 (5)
C20.9877 (2)0.73484 (16)0.48872 (18)0.0243 (5)
C30.5850 (3)0.73576 (19)0.4970 (2)0.0376 (7)
C40.4972 (3)0.7260 (2)0.5847 (2)0.0411 (7)
C50.2092 (2)0.53257 (19)0.3880 (2)0.0357 (6)
C60.1703 (2)0.4739 (2)0.2637 (2)0.0404 (7)
C70.2566 (3)0.4848 (2)0.1746 (2)0.0400 (7)
C80.3807 (2)0.55395 (19)0.2109 (2)0.0340 (6)
C90.4245 (2)0.61503 (16)0.33862 (19)0.0280 (5)
C100.3373 (2)0.60485 (17)0.42837 (19)0.0292 (5)
H10.722800.999900.192700.0290*
H21.009500.813400.472500.0290*
H30.670600.781100.526200.0450*
H40.526800.766300.668700.0490*
H50.151400.524900.445900.0430*
H60.086300.426500.237900.0480*
H70.228700.444700.090400.0480*
H80.436500.560800.151200.0410*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0250 (2)0.0143 (1)0.0206 (1)0.0024 (1)−0.0063 (1)−0.0023 (1)
O10.0403 (8)0.0154 (5)0.0213 (6)−0.0021 (5)0.0015 (5)−0.0004 (4)
O20.0341 (7)0.0218 (6)0.0316 (7)0.0032 (5)−0.0142 (6)−0.0024 (5)
O30.0340 (7)0.0157 (5)0.0215 (6)−0.0028 (5)0.0002 (5)0.0003 (4)
O40.0267 (6)0.0233 (6)0.0233 (6)−0.0048 (5)−0.0052 (5)0.0009 (5)
N10.0287 (8)0.0350 (9)0.0303 (8)−0.0032 (7)0.0082 (7)0.0034 (7)
N20.0380 (10)0.0450 (10)0.0316 (9)−0.0026 (8)0.0134 (7)0.0008 (7)
C10.0300 (9)0.0186 (8)0.0187 (7)0.0009 (7)0.0008 (6)0.0002 (6)
C20.0243 (9)0.0191 (8)0.0238 (9)−0.0003 (6)−0.0007 (7)−0.0011 (6)
C30.0331 (11)0.0429 (12)0.0358 (11)−0.0087 (9)0.0094 (9)−0.0020 (8)
C40.0442 (13)0.0482 (12)0.0309 (10)−0.0072 (10)0.0119 (9)−0.0050 (9)
C50.0323 (10)0.0386 (10)0.0381 (11)−0.0022 (8)0.0140 (8)0.0059 (9)
C60.0348 (11)0.0400 (11)0.0447 (12)−0.0105 (9)0.0102 (9)0.0004 (9)
C70.0428 (12)0.0412 (11)0.0337 (11)−0.0062 (9)0.0089 (9)−0.0041 (9)
C80.0342 (10)0.0378 (10)0.0305 (9)−0.0014 (8)0.0107 (8)0.0027 (8)
C90.0274 (9)0.0270 (9)0.0278 (9)0.0025 (7)0.0063 (7)0.0073 (7)
C100.0295 (10)0.0284 (9)0.0289 (9)0.0022 (7)0.0080 (7)0.0067 (7)
Geometric parameters (Å, °) top
Cu1—O11.9605 (11)C5—C61.371 (3)
Cu1—O21.9564 (14)C5—C101.417 (3)
Cu1—O3i1.9598 (12)C6—C71.411 (3)
Cu1—O4ii1.9489 (13)C7—C81.367 (3)
Cu1—N12.5150 (18)C8—C91.412 (3)
O1—C11.238 (2)C9—C101.423 (3)
O2—C21.248 (2)C1—H10.93
O3—C11.250 (2)C2—H20.93
O4—C21.246 (2)C3—H30.93
N1—C31.316 (3)C4—H40.93
N1—C91.377 (3)C5—H50.93
N2—C41.309 (3)C6—H60.93
N2—C101.376 (3)C7—H70.93
C3—C41.410 (4)C8—H80.93
O1—Cu1—O288.07 (5)C6—C7—C8120.55 (19)
O1—Cu1—O3i172.89 (6)C7—C8—C9120.31 (19)
O1—Cu1—O4ii90.52 (5)N1—C9—C8120.08 (18)
O2—Cu1—O3i88.43 (5)N1—C9—C10120.61 (17)
O2—Cu1—O4ii178.42 (5)C8—C9—C10119.31 (18)
O3i—Cu1—O4ii93.05 (5)N2—C10—C5119.66 (18)
O1—Cu1—N189.62 (6)N2—C10—C9121.20 (18)
O2—Cu1—N188.95 (6)C5—C10—C9119.14 (17)
O3i—Cu1—N196.50 (5)O1—C1—H1118
O4ii—Cu1—N190.32 (6)O3—C1—H1118
Cu1—O1—C1124.40 (11)O2—C2—H2118
Cu1—O2—C2130.44 (12)O4—C2—H2118
Cu1iii—O3—C1121.55 (11)N1—C3—H3119
Cu1iv—O4—C2128.06 (12)C4—C3—H3119
Cu1—N1—C3110.74 (15)N2—C4—H4118
Cu1—N1—C9132.68 (13)C3—C4—H4118
C3—N1—C9116.32 (19)C6—C5—H5120
C4—N2—C10116.02 (18)C10—C5—H5120
O1—C1—O3124.71 (17)C5—C6—H6120
O2—C2—O4123.02 (17)C7—C6—H6120
N1—C3—C4122.7 (2)C6—C7—H7120
N2—C4—C3123.19 (19)C8—C7—H7120
C6—C5—C10120.07 (18)C7—C8—H8120
C5—C6—C7120.6 (2)C9—C8—H8120
Symmetry codes: (i) −x+3/2, y−1/2, −z+1/2; (ii) x−1/2, −y+3/2, z−1/2; (iii) −x+3/2, y+1/2, −z+1/2; (iv) x+1/2, −y+3/2, z+1/2.
Table 1
Selected geometric parameters (Å, °) top
Cu1—O11.9605 (11)Cu1—O4ii1.9489 (13)
Cu1—O21.9564 (14)Cu1—N12.5150 (18)
Cu1—O3i1.9598 (12)
O1—Cu1—O288.07 (5)O3i—Cu1—O4ii93.05 (5)
O1—Cu1—O3i172.89 (6)O1—Cu1—N189.62 (6)
O1—Cu1—O4ii90.52 (5)O2—Cu1—N188.95 (6)
O2—Cu1—O3i88.43 (5)O3i—Cu1—N196.50 (5)
O2—Cu1—O4ii178.42 (5)O4ii—Cu1—N190.32 (6)
Symmetry codes: (i) −x+3/2, y−1/2, −z+1/2; (ii) x−1/2, −y+3/2, z−1/2.
Acknowledgements top

(no acknowledgements)

references
References top

Addison, A. W., Rao, T. N., Reedijk, J., van Rijn, J. & Verschoor, G. C. (1984). J. Chem. Soc. Dalton Trans. pp. 1349–1356.

Borthwick, P. W. (1980). Acta Cryst. B36, 628–632.

Macrae, C. F., Edgington, P. R., McCabe, P., Pidcock, E., Shields, G. P., Taylor, R., Towler, M. & van de Streek, J. (2006). J. Appl. Cryst. 39, 453–457.

Oxford Diffraction (2006). CrysAlis CCD and CrysAlis RED. Versions 1.171. Oxford Diffraction Ltd, Abingdon, Oxfordshire, England.

Sheldrick, G. M. (2003). SHELXTL. Version 6.14. Bruker AXS Inc., Madison, Wisconsin, USA.

Sieroń, L. (2003). Acta Cryst. E59, m803–m805.

Sieroń, L. (2007). Acta Cryst. C63, m199–m200.

Spek, A. L. (2003). J. Appl. Cryst. 36, 7–13.