Poly[[(N,N-dimethyl­formamide-κO)(μ₃-pyrazine-2,3-dicarboxyl­ato-κ⁴N¹,O²:O³:O³)copper(II)] monohydrate]

In the title compound, {[Cu(C₆H₂N₂O₄)(C₃H₇NO)]·H₂O}_n, the Cu(II) atom is coordinated by an N,O-bidentate pyrazine-2,3-dicarboxyl­ate (pzdc) dianion, two O atoms from two other pzdc anions and one O atom from the dimethlyformamide ligand, forming a distorted square-pyramidal CuNO₄ geometry. The polymeric character of the structure is established by the formation of layers parallel to (100) via bridging pzdc ligands. O—H...O hydrogen bonding between water mol­ecules and uncoordinated carboxyl­ate O atoms leads to additional stabilization of the structure.

Key indicators

• Single-crystal X-ray study
• T = 298 K
• Mean [sigma](C-C) = 0.006 Å
• R factor = 0.051
• wR factor = 0.115
• Data-to-parameter ratio = 12.7

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT230_ALERT_2_B Hirshfeld Test Diff for    O5     --  C7      ..       7.52 su

Alert level C
PLAT220_ALERT_2_C Large Non-Solvent    C     Ueq(max)/Ueq(min) ...       3.99 Ratio
PLAT222_ALERT_3_C Large Non-Solvent    H     Ueq(max)/Ueq(min) ...       3.65 Ratio
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Cu1    --  O3_d    ..       7.51 su
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for         N3
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600         21
PLAT731_ALERT_1_C Bond    Calc   0.825(15), Rep     0.82(5) ......       3.33 su-Ra
              O6   -H6B     1.555   1.555
PLAT732_ALERT_1_C Angle   Calc      114(6), Rep   113.5(19) ......       3.16 su-Ra
              H6A  -O6   -H6B     1.555   1.555   1.555
PLAT735_ALERT_1_C D-H     Calc   0.825(15), Rep     0.82(5) ......       3.33 su-Ra
              O6   -H6B     1.555   1.555
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600         17

Alert level G
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          3
PLAT380_ALERT_4_G Check Incorrectly? Oriented X(sp2)-Methyl Moiety         C8
PLAT710_ALERT_4_G Delete 1-2-3 or 2-3-4 Linear Torsion Angle ... #          2
            O3  -CU1 -O2  -C1     71.00  3.00   2.645   1.555   1.555   1.555

   0 ALERT level A = In general: serious problem
   1 ALERT level B = Potentially serious problem
   9 ALERT level C = Check and explain
   3 ALERT level G = General alerts; check

   3 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   4 ALERT type 2 Indicator that the structure model may be wrong or deficient
   3 ALERT type 3 Indicator that the structure quality may be low
   3 ALERT type 4 Improvement, methodology, query or suggestion
   0 ALERT type 5 Informative message, check

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S1. Comment

Polymeric compounds play an important role in the field of molecular magnetism. Di- and polycarboxylates are capable of bridging and providing effective magnetic exchange pathways. Pyrazine-2,3-dicarboxylic acid (H₂pzdc) has been widely applied to construct polymeric coordination compounds; their structures and magnetic properties were investigated (Li et al., 2004; Xiang et al., 2004; Hua & Liu, 2009; Lin et al., 2009; Tombul & Guven, 2009). We present here the structure of the title compound, {[Cu(pzdc)(DMF)]^.H₂O}_n, (I).

In the structure of compound (I), each Cu(II) atom is coordinated by an N atom of the pyrazine ring and a carboxylic O atom from one pzdc^2- anion, two O atoms from two other pzdc^2- anions, and O atom from DMF, forming a distorted square-pyramidal environment, as depicted in Fig. 1. The four atoms N1, O2, O5 and O3ⁱ form the basal plane, whereas the O3ⁱⁱ atom [symmetry code: (i) -x +1, y - 1/2, -z + 1; (ii) x, -y + 3/2, z -1/2] occupies the apical site with a longer Cu1—O3ⁱⁱ bond length of 2.378 (3) /%A. In the basal plane, the bond distances of Cu1—N1 and Cu1—O3ⁱ are 2.002 (3) and 1.958 (3) Å, which are shorter than those observed for the distorted square-pyramidal CuN₂O₃ coordination in a related structure of a Cu(II)pzdc derivative (Hua & Liu, 2009). The plane defined by carboxylic group O1—C1—C2—C3 is nearly coplanar to the pyrazine ring with the dihedral angle of 3.7 (7)°, while another carboxylate plane defined by the C2—C3—C6—O4 is approximately perpendicular to the pyrazine ring [dihedral angel of 92.9 (5)°]. This conformation was also observed in a series of other transition metal complexes formed with H₂pzdc (Li et al., 2004; Xiang et al., 2004; Konar et al., 2004; Hua et al., 2009). Extensive hydrogen bonding interactions help to stabilize the structure. The carboxylate O atoms take part in a O—H···O hydrogen bonding and are acceptor atoms with O atoms of water molecules as donator atoms (Table 1).

Related literature

For related structures with the pyrazine-2,3-dicarboxylate (pzdc) dianion, see: Hua & Liu (2009); Konar et al. (2004); Li et al. (2004); Lin et al. (2009); Tombul & Guven (2009); Wang et al. (2008); Xiang et al. (2004); Xu et al. (2008).

S2. Experimental

Mixed DMF and aqueous solution (15 ml) of CuCl₂^.2H₂O (0.5 mmol) and 2,3-pyrazinedicarboxylic acid ((H₂pzdc, 0.25 mmol) were slowly added into a methanolic (5 ml) solution of triethylene diamine (TED, 0.5 mmol); the resulting mixture was stirred for 5 minutes and allowed to stand at room temperature for about four days until blue single crystals were obtained.

S3. Refinement

H atoms of the water molecules were located in a difference Fourier map and were refined isotropically, with O—H and H—H distance restraints of 0.84 (1) Å and 1.37 (2) Å, respectively. The remaining H atoms were positioned geometrically (C—H = 0.93 Å) and allowed to ride on their parent atoms. The U_iso(H) values were set at 1.2U_eq(C) and 1.5U_eq(O).

Computing details

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); 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: SHELXTL (Sheldrick, 2008).

Figures

	Fig. 1. The coordination of the Cu(II) atom in the structure of compound (I), showing atom labels and 50% probability displacement ellipsoids for the non-H atoms.
	Fig. 2. The polymeric structure of compound (I); water molecules and DMF have been omitted for clarity.

Poly[[(N,N-dimethylformamide-κO)(µ₃-pyrazine-2,3- dicarboxylato-κ⁴N¹,O²:O³:O³)copper(II)] monohydrate]

Crystal data

[Cu(C6H2N2O4)(C3H7NO)]·H2O	F(000) = 652
Mr = 320.75	Dx = 1.682 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 1111 reflections
a = 10.1656 (5) Å	θ = 2.5–22.4°
b = 13.6310 (8) Å	µ = 1.75 mm^−1
c = 9.1461 (2) Å	T = 298 K
β = 91.430 (2)°	Prism, blue
V = 1266.96 (10) Å^3	0.39 × 0.10 × 0.06 mm
Z = 4

Data collection

Bruker APEX area-detector diffractometer	2283 independent reflections
Radiation source: fine-focus sealed tube	1600 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.058
phi and ω scans	θmax = 25.3°, θmin = 2.0°
Absorption correction: integration (SADABS; Bruker, 2002)	h = −8→12
Tmin = 0.549, Tmax = 0.902	k = −16→16
6222 measured reflections	l = −10→10

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)] = 0.051	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.115	H atoms treated by a mixture of independent and constrained refinement
S = 0.98	w = 1/[σ^2(Fo^2) + (0.0482P)^2] where P = (Fo^2 + 2Fc^2)/3
2283 reflections	(Δ/σ)max < 0.001
180 parameters	Δρmax = 0.48 e Å^−3
3 restraints	Δρmin = −0.34 e Å^−3

Special details

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
Cu1	0.59999 (5)	0.58784 (3)	0.07521 (6)	0.0402 (2)
O1	0.5775 (3)	0.8747 (2)	0.1085 (4)	0.0526 (10)
O2	0.6295 (3)	0.7254 (2)	0.0382 (4)	0.0463 (9)
O3	0.4380 (3)	0.9489 (2)	0.3914 (3)	0.0386 (8)
O4	0.2821 (3)	0.9362 (2)	0.2189 (4)	0.0511 (9)
O5	0.7494 (3)	0.5510 (2)	−0.0435 (4)	0.0503 (9)
O6	0.2218 (5)	0.1287 (3)	0.1467 (7)	0.121 (2)
N1	0.4710 (3)	0.6417 (2)	0.2162 (4)	0.0298 (8)
N2	0.3001 (3)	0.7442 (2)	0.3914 (4)	0.0402 (9)
N3	0.9066 (4)	0.5894 (4)	−0.2048 (5)	0.0655 (13)
C1	0.5654 (4)	0.7859 (3)	0.1145 (5)	0.0331 (10)
C2	0.4684 (4)	0.7404 (3)	0.2158 (4)	0.0279 (9)
C3	0.3821 (4)	0.7913 (3)	0.3018 (5)	0.0316 (10)
C4	0.3064 (4)	0.6467 (3)	0.3912 (5)	0.0420 (12)
H4	0.2516	0.6118	0.4523	0.050*
C5	0.3912 (4)	0.5951 (3)	0.3039 (5)	0.0381 (11)
H5	0.3920	0.5269	0.3071	0.046*
C6	0.3670 (4)	0.9018 (3)	0.3005 (5)	0.0352 (10)
C7	0.8054 (5)	0.6097 (4)	−0.1238 (6)	0.0554 (14)
H7	0.7732	0.6735	−0.1271	0.066*
C8	0.9664 (6)	0.6630 (5)	−0.2983 (8)	0.112 (3)
H8A	0.9216	0.7244	−0.2874	0.168*
H8B	0.9593	0.6421	−0.3985	0.168*
H8C	1.0575	0.6707	−0.2706	0.168*
C9	0.9607 (6)	0.4924 (5)	−0.2062 (7)	0.092 (2)
H9A	1.0486	0.4937	−0.1655	0.137*
H9B	0.9624	0.4688	−0.3051	0.137*
H9C	0.9073	0.4496	−0.1491	0.137*
H6A	0.277 (5)	0.148 (4)	0.089 (6)	0.110*
H6B	0.219 (6)	0.0685 (9)	0.155 (7)	0.110*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cu1	0.0472 (4)	0.0182 (3)	0.0560 (4)	0.0032 (2)	0.0188 (3)	0.0026 (3)
O1	0.075 (2)	0.0191 (15)	0.065 (3)	−0.0083 (15)	0.029 (2)	−0.0011 (16)
O2	0.0559 (19)	0.0221 (15)	0.062 (2)	−0.0013 (14)	0.0282 (17)	0.0013 (16)
O3	0.0467 (17)	0.0189 (14)	0.050 (2)	−0.0034 (13)	0.0072 (16)	−0.0062 (15)
O4	0.060 (2)	0.0361 (18)	0.057 (2)	0.0112 (16)	−0.0027 (19)	−0.0003 (17)
O5	0.047 (2)	0.0345 (17)	0.070 (3)	0.0050 (15)	0.0268 (18)	0.0034 (17)
O6	0.102 (4)	0.071 (3)	0.192 (6)	0.010 (3)	0.078 (4)	0.054 (4)
N1	0.0353 (19)	0.0157 (17)	0.039 (2)	−0.0021 (14)	0.0026 (17)	0.0003 (16)
N2	0.049 (2)	0.029 (2)	0.043 (2)	−0.0043 (17)	0.0103 (19)	−0.0032 (18)
N3	0.041 (2)	0.083 (3)	0.074 (4)	0.010 (2)	0.021 (2)	0.004 (3)
C1	0.040 (2)	0.025 (2)	0.034 (3)	−0.0004 (19)	0.008 (2)	−0.002 (2)
C2	0.036 (2)	0.019 (2)	0.029 (3)	−0.0042 (17)	−0.0021 (19)	−0.0008 (18)
C3	0.038 (2)	0.025 (2)	0.032 (3)	−0.0013 (18)	−0.001 (2)	−0.0019 (19)
C4	0.052 (3)	0.030 (2)	0.045 (3)	−0.010 (2)	0.011 (2)	0.002 (2)
C5	0.050 (3)	0.021 (2)	0.044 (3)	−0.004 (2)	0.007 (2)	0.000 (2)
C6	0.039 (2)	0.026 (2)	0.041 (3)	0.004 (2)	0.014 (2)	0.004 (2)
C7	0.043 (3)	0.053 (3)	0.070 (4)	0.009 (2)	0.005 (3)	−0.007 (3)
C8	0.072 (4)	0.144 (7)	0.121 (7)	0.014 (4)	0.049 (4)	0.053 (5)
C9	0.062 (4)	0.098 (5)	0.116 (6)	0.011 (4)	0.030 (4)	−0.050 (4)

Geometric parameters (Å, º)

Cu1—O2	1.930 (3)	N2—C3	1.346 (5)
Cu1—O5	1.954 (3)	N3—C7	1.313 (6)
Cu1—O3^i	1.958 (3)	N3—C9	1.432 (6)
Cu1—N1	2.002 (3)	N3—C8	1.460 (7)
Cu1—O3^ii	2.378 (3)	C1—C2	1.504 (5)
O1—C1	1.218 (5)	C2—C3	1.380 (5)
O2—C1	1.271 (5)	C3—C6	1.515 (5)
O3—C6	1.263 (5)	C4—C5	1.381 (6)
O3—Cu1^iii	1.958 (3)	C4—H4	0.9300
O3—Cu1^iv	2.378 (3)	C5—H5	0.9300
O4—C6	1.220 (5)	C7—H7	0.9300
O5—C7	1.235 (6)	C8—H8A	0.9600
O6—H6A	0.82 (5)	C8—H8B	0.9600
O6—H6B	0.82 (5)	C8—H8C	0.9600
N1—C5	1.318 (5)	C9—H9A	0.9600
N1—C2	1.344 (4)	C9—H9B	0.9600
N2—C4	1.331 (5)	C9—H9C	0.9600
O2—Cu1—O5	91.48 (13)	C3—C2—C1	125.4 (4)
O2—Cu1—O3^i	177.39 (13)	N2—C3—C2	121.3 (4)
O5—Cu1—O3^i	89.82 (13)	N2—C3—C6	114.5 (4)
O2—Cu1—N1	82.17 (12)	C2—C3—C6	124.2 (4)
O5—Cu1—N1	169.37 (13)	N2—C4—C5	122.6 (4)
O3^i—Cu1—N1	96.87 (12)	N2—C4—H4	118.7
O2—Cu1—O3^ii	100.87 (12)	C5—C4—H4	118.7
O5—Cu1—O3^ii	94.99 (12)	N1—C5—C4	120.6 (4)
O3^i—Cu1—O3^ii	76.75 (12)	N1—C5—H5	119.7
N1—Cu1—O3^ii	94.57 (12)	C4—C5—H5	119.7
C1—O2—Cu1	116.7 (3)	O4—C6—O3	126.2 (4)
C6—O3—Cu1^iii	118.9 (3)	O4—C6—C3	117.2 (4)
C6—O3—Cu1^iv	137.1 (3)	O3—C6—C3	116.4 (4)
Cu1^iii—O3—Cu1^iv	103.25 (12)	O5—C7—N3	125.4 (5)
C7—O5—Cu1	122.7 (3)	O5—C7—H7	117.3
H6A—O6—H6B	113.5 (19)	N3—C7—H7	117.3
C5—N1—C2	118.1 (4)	N3—C8—H8A	109.5
C5—N1—Cu1	129.7 (3)	N3—C8—H8B	109.5
C2—N1—Cu1	112.2 (3)	H8A—C8—H8B	109.5
C4—N2—C3	116.4 (4)	N3—C8—H8C	109.5
C7—N3—C9	120.4 (5)	H8A—C8—H8C	109.5
C7—N3—C8	121.9 (5)	H8B—C8—H8C	109.5
C9—N3—C8	117.6 (5)	N3—C9—H9A	109.5
O1—C1—O2	124.5 (4)	N3—C9—H9B	109.5
O1—C1—C2	120.4 (4)	H9A—C9—H9B	109.5
O2—C1—C2	115.1 (3)	N3—C9—H9C	109.5
N1—C2—C3	121.0 (4)	H9A—C9—H9C	109.5
N1—C2—C1	113.7 (3)	H9B—C9—H9C	109.5
O5—Cu1—O2—C1	−169.1 (3)	O1—C1—C2—C3	3.7 (7)
O3^i—Cu1—O2—C1	71 (3)	O2—C1—C2—C3	−175.6 (4)
N1—Cu1—O2—C1	2.3 (3)	C4—N2—C3—C2	−0.4 (6)
O3^ii—Cu1—O2—C1	95.5 (3)	C4—N2—C3—C6	177.3 (4)
O2—Cu1—O5—C7	−11.7 (4)	N1—C2—C3—N2	1.5 (6)
O3^i—Cu1—O5—C7	166.0 (4)	C1—C2—C3—N2	−178.8 (4)
N1—Cu1—O5—C7	−64.7 (9)	N1—C2—C3—C6	−176.0 (4)
O3^ii—Cu1—O5—C7	89.4 (4)	C1—C2—C3—C6	3.7 (7)
O2—Cu1—N1—C5	179.2 (4)	C3—N2—C4—C5	−0.5 (6)
O5—Cu1—N1—C5	−127.0 (7)	C2—N1—C5—C4	0.8 (6)
O3^i—Cu1—N1—C5	1.7 (4)	Cu1—N1—C5—C4	−178.4 (3)
O3^ii—Cu1—N1—C5	78.9 (4)	N2—C4—C5—N1	0.3 (7)
O2—Cu1—N1—C2	0.1 (3)	Cu1^iii—O3—C6—O4	7.2 (6)
O5—Cu1—N1—C2	53.8 (8)	Cu1^iv—O3—C6—O4	175.4 (3)
O3^i—Cu1—N1—C2	−177.5 (3)	Cu1^iii—O3—C6—C3	−167.7 (3)
O3^ii—Cu1—N1—C2	−100.3 (3)	Cu1^iv—O3—C6—C3	0.5 (6)
Cu1—O2—C1—O1	176.6 (4)	N2—C3—C6—O4	−84.7 (5)
Cu1—O2—C1—C2	−4.1 (5)	C2—C3—C6—O4	92.9 (5)
C5—N1—C2—C3	−1.6 (6)	N2—C3—C6—O3	90.7 (4)
Cu1—N1—C2—C3	177.6 (3)	C2—C3—C6—O3	−91.7 (5)
C5—N1—C2—C1	178.7 (4)	Cu1—O5—C7—N3	179.4 (4)
Cu1—N1—C2—C1	−2.1 (4)	C9—N3—C7—O5	0.6 (9)
O1—C1—C2—N1	−176.6 (4)	C8—N3—C7—O5	179.3 (6)
O2—C1—C2—N1	4.1 (5)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O6—H6B···O4^v	0.82 (5)	2.00 (3)	2.771 (5)	156 (7)
O6—H6A···O1^vi	0.82 (5)	2.38 (3)	3.138 (6)	153 (5)
O6—H6A···O2^vi	0.82 (5)	2.30 (3)	3.037 (5)	149 (5)

Symmetry codes: (v) x, y−1, z; (vi) −x+1, −y+1, −z.