metal-organic compounds\(\def\hfill{\hskip 5em}\def\hfil{\hskip 3em}\def\eqno#1{\hfil {#1}}\)

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ISSN: 2056-9890

catena-Poly[[bis­­(1-ethyl-1H-imidazole-κN3)copper(II)]-μ-oxalato-κ4O1,O2:O1′,O2′]

aOrdered Matter Science Research Center, College of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189, People's Republic of China
*Correspondence e-mail: xqchem@yahoo.com.cn

(Received 3 October 2011; accepted 18 October 2011; online 22 October 2011)

The title compound, [Cu(C2O4)(C5H8N2)2]n, is composed of one-dimensional linear chains running parallel to the a axis. In the chain, trans-[Cu(imidazole)2]2+ units are sequentially bridged by bis-bidentate oxalate ligands, resulting in an octa­hedral CuO4N2 donor set. The Cu⋯Cu separation through the oxalate bridge is 5.620 (5) Å. Both the Cu atoms and the C—C bond of the oxalate bridge are bis­ected by inversion centres.

Related literature

For general background on ferroelectric organic compounds with framework structures, see: Fu et al. (2009[Fu, D.-W., Ge, J.-Z., Dai, J., Ye, H.-Y. & Qu, Z.-R. (2009). Inorg. Chem. Commun. 12, 994-997.]); Ye et al. (2006[Ye, Q., Song, Y.-M., Wang, G.-X., Chen, K. & Fu, D.-W. (2006). J. Am. Chem. Soc. 128, 6554-6555.]); Zhang et al. (2008[Zhang, W., Xiong, R.-G. & Huang, S.-P. D. (2008). J. Am. Chem. Soc. 130, 10468-10469.], 2010[Zhang, W., Ye, H.-Y., Cai, H.-L., Ge, J.-Z. & Xiong, R.-G. (2010). J. Am. Chem. Soc. 132, 7300-7302.]).

[Scheme 1]

Experimental

Crystal data
  • [Cu(C2O4)(C5H8N2)2]

  • Mr = 343.83

  • Monoclinic, P 21 /n

  • a = 5.6200 (11) Å

  • b = 8.8577 (18) Å

  • c = 14.481 (3) Å

  • β = 96.55 (3)°

  • V = 716.2 (2) Å3

  • Z = 2

  • Mo Kα radiation

  • μ = 1.55 mm−1

  • T = 293 K

  • 0.30 × 0.25 × 0.20 mm

Data collection
  • Rigaku SCXmini diffractometer

  • Absorption correction: multi-scan (CrystalClear; Rigaku, 2005[Rigaku (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.]) Tmin = 0.635, Tmax = 0.734

  • 7300 measured reflections

  • 1653 independent reflections

  • 1267 reflections with I > 2σ(I)

  • Rint = 0.062

Refinement
  • R[F2 > 2σ(F2)] = 0.040

  • wR(F2) = 0.092

  • S = 1.05

  • 1653 reflections

  • 98 parameters

  • H-atom parameters constrained

  • Δρmax = 0.48 e Å−3

  • Δρmin = −0.33 e Å−3

Data collection: CrystalClear (Rigaku, 2005[Rigaku (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.]); cell refinement: CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); molecular graphics: SHELXTL (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]); software used to prepare material for publication: SHELXL97.

Supporting information


Comment top

As part of our ongoing study of potential ferroelectric materials we have determined the structure of the present copper complex and examined its dielectric behaviour with temperature. This is the usual method for detecting these materials (Fu et al., 2009; Ye et al., 2006; Zhang et al., 2008; Zhang et al., 2010). Unfortunately, the dielectric constant for the title compound, Cu[C5H8N]2C2O4, (I) does not show any behavior indicating the onset of a ferroelectric phase change over the range 80 K to 298 K (m.p.319–329).

The Cu atoms are located on crystallographic inversion centers, and are coordinated to four oxygen atoms of two bridging oxalato ligands, also bisected by inversion centres, and two endocyclic nitrogen atoms from two crystallograhically related imidazole molecules, resulting in octahedral MO4N2 donor sets. Fig. 2 suggests the way in which oxalato-bridged chains build up. The Cu — Cu intrachain separation is 5.620 (5) Å.

Related literature top

For general background on ferroelectric organic frameworks, see: Fu et al. (2009); Ye et al. (2006); Zhang et al. (2008, 2010).

Experimental top

A mixture of 1-ethyl imidazole (1.9 g, 20 mmol), cupric oxalate (1.5 g, 10 mmol) in water was stirred for several days at ambient temperature; blue block crystals were obtained on standing.

Refinement top

All H atoms were placed in geometrically idealized positions and constrained to ride on their parent atoms with C—H = 0.93–0.96 Å, and with Uĩso(H) = 1.2 Uĩso(C) or 1.5 Uĩso(C) for ethy H atoms..

Computing details top

Data collection: CrystalClear (Rigaku, 2005); cell refinement: CrystalClear (Rigaku, 2005); data reduction: CrystalClear (Rigaku, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Ellipsoid plot of (I), ( 50% probability level). Symmetry codes A: -x, 1-y, 1-z. B: 1-x, 1-y, 1-z. C: -1+x, y, z.
[Figure 2] Fig. 2. Packing diagram of the title compound showing the way in which chains are built up.
catena-Poly[[bis(1-ethyl-1Himidazole-κN3)copper(II)]- µ-oxalato-κ4O1,O2:O1',O2'] top
Crystal data top
[Cu(C2O4)(C5H8N2)2]F(000) = 354
Mr = 343.83Dx = 1.594 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 1653 reflections
a = 5.6200 (11) Åθ = 2.3–27.5°
b = 8.8577 (18) ŵ = 1.55 mm1
c = 14.481 (3) ÅT = 293 K
β = 96.55 (3)°Block, blue
V = 716.2 (2) Å30.30 × 0.25 × 0.20 mm
Z = 2
Data collection top
Rigaku SCXmini
diffractometer
1267 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tubeRint = 0.062
Graphite monochromatorθmax = 27.5°, θmin = 3.7°
ω scansh = 77
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)
k = 1111
Tmin = 0.635, Tmax = 0.734l = 1818
7300 measured reflections2 standard reflections every 150 reflections
1653 independent reflections intensity decay: none
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.040Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.092H-atom parameters constrained
S = 1.05 w = 1/[σ2(Fo2) + (0.0361P)2 + 0.3394P]
where P = (Fo2 + 2Fc2)/3
1653 reflections(Δ/σ)max < 0.001
98 parametersΔρmax = 0.48 e Å3
0 restraintsΔρmin = 0.33 e Å3
Crystal data top
[Cu(C2O4)(C5H8N2)2]V = 716.2 (2) Å3
Mr = 343.83Z = 2
Monoclinic, P21/nMo Kα radiation
a = 5.6200 (11) ŵ = 1.55 mm1
b = 8.8577 (18) ÅT = 293 K
c = 14.481 (3) Å0.30 × 0.25 × 0.20 mm
β = 96.55 (3)°
Data collection top
Rigaku SCXmini
diffractometer
1267 reflections with I > 2σ(I)
Absorption correction: multi-scan
(CrystalClear; Rigaku, 2005)
Rint = 0.062
Tmin = 0.635, Tmax = 0.7342 standard reflections every 150 reflections
7300 measured reflections intensity decay: none
1653 independent reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0400 restraints
wR(F2) = 0.092H-atom parameters constrained
S = 1.05Δρmax = 0.48 e Å3
1653 reflectionsΔρmin = 0.33 e Å3
98 parameters
Special details top

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 (Å2) top
xyzUiso*/Ueq
Cu10.00000.50000.50000.02341 (16)
C10.0677 (5)0.4366 (4)0.3025 (2)0.0326 (7)
H10.14520.34630.31940.039*
C20.1151 (5)0.6469 (4)0.3090 (2)0.0365 (7)
H20.19000.73040.33180.044*
C30.0853 (6)0.6229 (4)0.2184 (2)0.0397 (8)
H30.13370.68610.16850.048*
C40.1083 (6)0.4132 (4)0.1331 (2)0.0439 (8)
H4A0.02270.41360.08330.053*
H4B0.14770.30880.14820.053*
C50.3213 (7)0.4885 (4)0.0999 (3)0.0534 (9)
H5A0.28010.58990.08090.080*
H5B0.37010.43330.04820.080*
H5C0.45050.49060.14940.080*
C60.4839 (4)0.4123 (3)0.49195 (17)0.0210 (5)
N10.0177 (4)0.5292 (3)0.36168 (15)0.0282 (6)
N20.0296 (4)0.4876 (3)0.21516 (16)0.0339 (6)
O10.3372 (3)0.6619 (2)0.52150 (13)0.0291 (5)
O20.2754 (3)0.3599 (2)0.49398 (12)0.0259 (4)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cu10.0188 (2)0.0301 (3)0.0218 (2)0.0016 (2)0.00409 (16)0.0002 (2)
C10.0357 (16)0.0345 (16)0.0279 (16)0.0039 (14)0.0056 (13)0.0016 (13)
C20.0367 (16)0.0403 (18)0.0333 (16)0.0065 (14)0.0067 (13)0.0027 (14)
C30.0414 (17)0.0478 (19)0.0291 (16)0.0012 (16)0.0010 (13)0.0095 (15)
C40.050 (2)0.056 (2)0.0266 (16)0.0079 (17)0.0082 (14)0.0087 (15)
C50.063 (2)0.050 (2)0.052 (2)0.0054 (19)0.0277 (19)0.0000 (18)
C60.0211 (12)0.0244 (14)0.0172 (12)0.0034 (12)0.0008 (10)0.0010 (11)
N10.0265 (12)0.0336 (15)0.0248 (12)0.0027 (10)0.0048 (10)0.0015 (10)
N20.0358 (13)0.0422 (15)0.0238 (12)0.0023 (12)0.0042 (10)0.0010 (11)
O10.0235 (9)0.0270 (11)0.0374 (11)0.0020 (8)0.0069 (8)0.0030 (9)
O20.0197 (9)0.0269 (10)0.0316 (10)0.0014 (8)0.0054 (8)0.0003 (9)
Geometric parameters (Å, º) top
Cu1—O21.9935 (18)C3—H30.9300
Cu1—O2i1.9935 (18)C4—N21.470 (4)
Cu1—N12.011 (2)C4—C51.497 (4)
Cu1—N1i2.011 (2)C4—H4A0.9700
Cu1—O1i2.3684 (18)C4—H4B0.9700
Cu1—O12.3684 (19)C5—H5A0.9600
C1—N11.316 (4)C5—H5B0.9600
C1—N21.337 (4)C5—H5C0.9600
C1—H10.9300C6—O1ii1.235 (3)
C2—C31.359 (4)C6—O21.264 (3)
C2—N11.368 (4)C6—C6ii1.579 (5)
C2—H20.9300O1—C6ii1.235 (3)
C3—N21.365 (4)
O2—Cu1—O2i180.000 (1)N2—C4—C5112.7 (3)
O2—Cu1—N189.27 (8)N2—C4—H4A109.1
O2i—Cu1—N190.73 (8)C5—C4—H4A109.1
O2—Cu1—N1i90.73 (8)N2—C4—H4B109.1
O2i—Cu1—N1i89.27 (8)C5—C4—H4B109.1
N1—Cu1—N1i180.000 (1)H4A—C4—H4B107.8
O2—Cu1—O1i103.35 (7)C4—C5—H5A109.5
O2i—Cu1—O1i76.65 (7)C4—C5—H5B109.5
N1—Cu1—O1i89.94 (8)H5A—C5—H5B109.5
N1i—Cu1—O1i90.06 (8)C4—C5—H5C109.5
O2—Cu1—O176.65 (7)H5A—C5—H5C109.5
O2i—Cu1—O1103.35 (7)H5B—C5—H5C109.5
N1—Cu1—O190.06 (8)O1ii—C6—O2125.6 (2)
N1i—Cu1—O189.94 (8)O1ii—C6—C6ii117.7 (3)
O1i—Cu1—O1180.00 (7)O2—C6—C6ii116.7 (3)
N1—C1—N2112.0 (3)C1—N1—C2105.3 (2)
N1—C1—H1124.0C1—N1—Cu1126.0 (2)
N2—C1—H1124.0C2—N1—Cu1128.6 (2)
C3—C2—N1109.5 (3)C1—N2—C3106.8 (2)
C3—C2—H2125.2C1—N2—C4125.6 (3)
N1—C2—H2125.2C3—N2—C4127.5 (3)
C2—C3—N2106.3 (3)C6ii—O1—Cu1108.12 (16)
C2—C3—H3126.8C6—O2—Cu1119.93 (16)
N2—C3—H3126.8
Symmetry codes: (i) x, y+1, z+1; (ii) x+1, y+1, z+1.

Experimental details

Crystal data
Chemical formula[Cu(C2O4)(C5H8N2)2]
Mr343.83
Crystal system, space groupMonoclinic, P21/n
Temperature (K)293
a, b, c (Å)5.6200 (11), 8.8577 (18), 14.481 (3)
β (°) 96.55 (3)
V3)716.2 (2)
Z2
Radiation typeMo Kα
µ (mm1)1.55
Crystal size (mm)0.30 × 0.25 × 0.20
Data collection
DiffractometerRigaku SCXmini
diffractometer
Absorption correctionMulti-scan
(CrystalClear; Rigaku, 2005)
Tmin, Tmax0.635, 0.734
No. of measured, independent and
observed [I > 2σ(I)] reflections
7300, 1653, 1267
Rint0.062
(sin θ/λ)max1)0.649
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.040, 0.092, 1.05
No. of reflections1653
No. of parameters98
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)0.48, 0.33

Computer programs: CrystalClear (Rigaku, 2005), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), SHELXTL (Sheldrick, 2008).

 

Acknowledgements

This work was supported by Southeast University.

References

First citationFu, D.-W., Ge, J.-Z., Dai, J., Ye, H.-Y. & Qu, Z.-R. (2009). Inorg. Chem. Commun. 12, 994–997.  Web of Science CSD CrossRef CAS Google Scholar
First citationRigaku (2005). CrystalClear. Rigaku Corporation, Tokyo, Japan.  Google Scholar
First citationSheldrick, G. M. (2008). Acta Cryst. A64, 112–122.  Web of Science CrossRef CAS IUCr Journals Google Scholar
First citationYe, Q., Song, Y.-M., Wang, G.-X., Chen, K. & Fu, D.-W. (2006). J. Am. Chem. Soc. 128, 6554–6555.  Web of Science CSD CrossRef PubMed CAS Google Scholar
First citationZhang, W., Xiong, R.-G. & Huang, S.-P. D. (2008). J. Am. Chem. Soc. 130, 10468–10469.  Web of Science CSD CrossRef PubMed CAS Google Scholar
First citationZhang, W., Ye, H.-Y., Cai, H.-L., Ge, J.-Z. & Xiong, R.-G. (2010). J. Am. Chem. Soc. 132, 7300–7302.  Web of Science CSD CrossRef CAS PubMed Google Scholar

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ISSN: 2056-9890
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