Poly[diimidazole-μ(4)-oxalato-μ(2)-oxalato-dicopper(II)].

The title compound, [Cu(2)(C(2)O(4))(2)(C(3)H(4)N(2))(2)](n), was obtained as an unexpected product under hydro-thermal conditions. The Cu(II) atom is in a Jahn-Teller-distorted octa-hedral environment formed by one imidazole N atom and five O atoms from three oxalate anions. The two independent oxalate anions are situated on centres of inversion and coordinate to the Cu(II) atom in two different modes, viz. bidentate and monodentate. The bidentate anions bridge two Cu(II) atoms, whereas the monodentate anions bridge four Cu(II) atoms, leading to a layered arrangement parallel to (100). These layers are further linked into a final three-dimensional network structure via inter-molecular N-H⋯O hydrogen bonds. The title compound is isotypic with the Zn analogue.

Related literature

For background to oxalates, see: Ghosh et al. (2004 ▶); Ye & Lin (2010 ▶). For the isotypic Zn analogue, see: Lu et al. (2005 ▶).

Experimental

Crystal data

[Cu2(C2O4)2(C3H4N2)2]

M = 439.28

Monoclinic,

a = 8.3367 (4) Å

b = 9.3131 (5) Å

c = 8.4838 (5) Å

β = 92.352 (3)°

V = 658.13 (6) Å3

Z = 2

Mo Kα radiation

μ = 3.29 mm−1

T = 296 K

0.28 × 0.18 × 0.06 mm

Data collection

Bruker APEXII CCD diffractometer

Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T min = 0.497, T max = 0.821

10313 measured reflections

1511 independent reflections

1362 reflections with I > 2σ(I)

R int = 0.028

Refinement

R[F 2 > 2σ(F 2)] = 0.022

wR(F 2) = 0.062

S = 1.09

1511 reflections

109 parameters

H-atom parameters constrained

Δρmax = 0.49 e Å−3

Δρmin = −0.42 e Å−3

Data collection: APEX2 (Bruker, 2006 ▶); cell refinement: SAINT (Bruker, 2006 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg, 2006 ▶); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536811015777/wm2473sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536811015777/wm2473Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

[Cu2(C2O4)2(C3H4N2)2]	F(000) = 436
Mr = 439.28	Dx = 2.217 Mg m−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 4365 reflections
a = 8.3367 (4) Å	θ = 2.5–27.6°
b = 9.3131 (5) Å	µ = 3.29 mm−1
c = 8.4838 (5) Å	T = 296 K
β = 92.352 (3)°	Block, green
V = 658.13 (6) Å3	0.28 × 0.18 × 0.06 mm
Z = 2

Bruker APEXII CCD diffractometer	1511 independent reflections
Radiation source: fine-focus sealed tube	1362 reflections with I > 2σ(I)
graphite	Rint = 0.028
ω scans	θmax = 27.6°, θmin = 2.5°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −10→9
Tmin = 0.497, Tmax = 0.821	k = −12→12
10313 measured reflections	l = −11→10

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)] = 0.022	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.062	H-atom parameters constrained
S = 1.09	w = 1/[σ2(Fo2) + (0.0335P)2 + 0.3353P] where P = (Fo2 + 2Fc2)/3
1511 reflections	(Δ/σ)max = 0.001
109 parameters	Δρmax = 0.49 e Å−3
0 restraints	Δρmin = −0.42 e Å−3

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.

	x	y	z	Uiso*/Ueq
Cu1	−0.87721 (3)	0.23821 (2)	−0.10302 (3)	0.02435 (10)
O1	−0.80090 (16)	0.04677 (14)	−0.02324 (17)	0.0263 (3)
O2	−0.90639 (16)	−0.15701 (14)	0.06412 (17)	0.0265 (3)
O3	−0.97708 (18)	0.41685 (14)	−0.18398 (16)	0.0277 (3)
O4	−0.91189 (18)	0.37282 (15)	0.12789 (17)	0.0296 (3)
N1	−0.6552 (2)	0.30160 (19)	−0.1281 (2)	0.0294 (4)
N2	−0.3925 (2)	0.2996 (3)	−0.1154 (3)	0.0450 (5)
H2A	−0.2956	0.2704	−0.0975	0.054*
C1	−0.9154 (2)	−0.03131 (19)	0.0114 (2)	0.0214 (4)
C2	−1.0193 (2)	0.51365 (19)	−0.0895 (2)	0.0225 (4)
C3	−0.5993 (3)	0.4276 (3)	−0.1902 (3)	0.0411 (5)
H3A	−0.6631	0.5019	−0.2305	0.049*
C4	−0.4374 (3)	0.4264 (3)	−0.1836 (3)	0.0483 (6)
H4A	−0.3699	0.4981	−0.2186	0.058*
C5	−0.5252 (3)	0.2292 (2)	−0.0814 (3)	0.0400 (6)
H5A	−0.5266	0.1404	−0.0313	0.048*

	U11	U22	U33	U12	U13	U23
Cu1	0.02007 (15)	0.01856 (14)	0.03460 (17)	0.00096 (8)	0.00343 (10)	0.00411 (9)
O1	0.0212 (7)	0.0228 (6)	0.0351 (8)	−0.0002 (5)	0.0017 (6)	0.0042 (6)
O2	0.0215 (7)	0.0203 (6)	0.0377 (8)	0.0020 (5)	0.0023 (6)	0.0040 (5)
O3	0.0356 (8)	0.0206 (6)	0.0269 (7)	0.0042 (5)	0.0015 (6)	0.0004 (5)
O4	0.0369 (8)	0.0235 (7)	0.0284 (7)	0.0072 (6)	0.0001 (6)	0.0016 (5)
N1	0.0244 (8)	0.0261 (8)	0.0379 (10)	−0.0009 (7)	0.0034 (7)	0.0014 (7)
N2	0.0216 (10)	0.0462 (12)	0.0670 (15)	0.0008 (8)	0.0001 (9)	0.0017 (10)
C1	0.0204 (9)	0.0217 (8)	0.0222 (9)	0.0022 (7)	0.0013 (7)	−0.0013 (7)
C2	0.0224 (9)	0.0214 (8)	0.0238 (10)	−0.0019 (7)	0.0008 (7)	0.0019 (7)
C3	0.0339 (12)	0.0401 (12)	0.0490 (14)	−0.0052 (10)	−0.0025 (10)	0.0143 (10)
C4	0.0334 (12)	0.0551 (15)	0.0561 (16)	−0.0138 (11)	−0.0001 (11)	0.0164 (13)
C5	0.0272 (12)	0.0303 (11)	0.0624 (16)	0.0021 (8)	0.0015 (11)	0.0043 (10)

Cu1—N1	1.9624 (18)	N1—C3	1.375 (3)
Cu1—O3	1.9713 (13)	N2—C5	1.328 (3)
Cu1—O2i	1.9960 (14)	N2—C4	1.361 (3)
Cu1—O1	2.0016 (13)	N2—H2A	0.8600
Cu1—O4	2.3536 (14)	C1—C1i	1.532 (4)
Cu1—O4ii	2.512 (1)	C2—O4iii	1.240 (2)
O1—C1	1.245 (2)	C2—C2iii	1.560 (4)
O2—C1	1.254 (2)	C3—C4	1.348 (3)
O2—Cu1i	1.9960 (14)	C3—H3A	0.9300
O3—C2	1.266 (2)	C4—H4A	0.9300
O4—C2iii	1.240 (2)	C5—H5A	0.9300
N1—C5	1.323 (3)
N1—Cu1—O3	95.45 (7)	C3—N1—Cu1	129.37 (16)
N1—Cu1—O2i	174.07 (6)	C5—N2—C4	107.7 (2)
O3—Cu1—O2i	90.33 (6)	C5—N2—H2A	126.2
N1—Cu1—O1	90.95 (6)	C4—N2—H2A	126.2
O3—Cu1—O1	173.43 (6)	O1—C1—O2	126.46 (17)
O2i—Cu1—O1	83.31 (5)	O1—C1—C1i	117.3 (2)
N1—Cu1—O4	94.51 (7)	O2—C1—C1i	116.2 (2)
O3—Cu1—O4	77.05 (5)	O4iii—C2—O3	125.35 (17)
O2i—Cu1—O4	85.50 (6)	O4iii—C2—C2iii	118.0 (2)
O1—Cu1—O4	103.96 (5)	O3—C2—C2iii	116.7 (2)
O1—Cu1—O4ii	87.92 (5)	C4—C3—N1	109.4 (2)
O4—Cu1—O4ii	164.20 (6)	C4—C3—H3A	125.3
O3—Cu1—O4ii	89.98 (5)	N1—C3—H3A	125.3
N1—Cu1—O4ii	95.69 (6)	C3—C4—N2	106.4 (2)
C1—O1—Cu1	111.35 (12)	C3—C4—H4A	126.8
C1—O2—Cu1i	111.80 (12)	N2—C4—H4A	126.8
C2—O3—Cu1	120.32 (12)	N1—C5—N2	111.3 (2)
C2iii—O4—Cu1	107.87 (12)	N1—C5—H5A	124.4
C5—N1—C3	105.23 (19)	N2—C5—H5A	124.4
C5—N1—Cu1	125.38 (16)
N1—Cu1—O1—C1	178.87 (13)	O2i—Cu1—N1—C3	−170.1 (6)
O3—Cu1—O1—C1	−14.0 (6)	O1—Cu1—N1—C3	175.6 (2)
O2i—Cu1—O1—C1	0.34 (13)	O4—Cu1—N1—C3	−80.3 (2)
O4—Cu1—O1—C1	83.99 (13)	Cu1—O1—C1—O2	179.88 (16)
N1—Cu1—O3—C2	−96.29 (15)	Cu1—O1—C1—C1i	−0.4 (3)
O2i—Cu1—O3—C2	82.40 (15)	Cu1i—O2—C1—O1	179.67 (16)
O1—Cu1—O3—C2	96.7 (5)	Cu1i—O2—C1—C1i	0.0 (2)
O4—Cu1—O3—C2	−2.90 (14)	Cu1—O3—C2—O4iii	−177.21 (15)
N1—Cu1—O4—C2iii	97.23 (13)	Cu1—O3—C2—C2iii	2.8 (3)
O3—Cu1—O4—C2iii	2.66 (13)	C5—N1—C3—C4	1.7 (3)
O2i—Cu1—O4—C2iii	−88.72 (13)	Cu1—N1—C3—C4	179.68 (18)
O1—Cu1—O4—C2iii	−170.67 (12)	N1—C3—C4—N2	−0.6 (3)
O3—Cu1—N1—C5	174.7 (2)	C5—N2—C4—C3	−0.7 (3)
O2i—Cu1—N1—C5	7.6 (8)	C3—N1—C5—N2	−2.1 (3)
O1—Cu1—N1—C5	−6.7 (2)	Cu1—N1—C5—N2	179.75 (17)
O4—Cu1—N1—C5	97.3 (2)	C4—N2—C5—N1	1.8 (3)
O3—Cu1—N1—C3	−2.9 (2)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2A···O2iv	0.86	2.00	2.841 (2)	167

Table 1

Selected bond lengths (Å)

Cu1—N1	1.9624 (18)
Cu1—O3	1.9713 (13)
Cu1—O2i	1.9960 (14)
Cu1—O1	2.0016 (13)
Cu1—O4	2.3536 (14)
Cu1—O4ii	2.512 (1)

Symmetry codes: (i) ; (ii) .

Table 2

Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H2A⋯O2iii	0.86	2.00	2.841 (2)	167

Symmetry code: (iii) .