catena-Poly[[di-aqua-bis-(4-formyl-benzoato-κO (1))copper(II)]-μ-pyrazine-κ(2) N:N'].

In the title polymeric compound, [Cu(C8H5O3)2(C4H4N2)(H2O)2] n , the Cu(II) atom is located on a twofold rotation axis and has a slightly distorted octa-hedral coordination sphere. In the equatorial plane, it is coordinated by two carboxyl-ate O atoms of two symmetry-related monodentate formyl-benzoate anions and by two N atoms of the bridging pyrazine ligand, which is bis-ected by the twofold rotation axis. The axial positions are occupied by two O atoms of the coordinating water mol-ecules. In the formyl-benzoate anion, the carboxyl-ate group is twisted away from the attached benzene ring by 6.2 (2)°, while the benzene and pyrazine rings are oriented at a dihedral angle of 68.91 (8)°. The pyrazine ligands bridge the Cu(II) cations, forming polymeric chains running along the b-axis direction. Strong intra-molecular O-H⋯O hydrogen bonds link the water mol-ecules to the carboxyl-ate O atoms. In the crystal, O-Hwater⋯Owater hydrogen bonds link adjacent chains into layers parallel to the bc plane. The layers are linked via C-Hpyrazine⋯Oform-yl hydrogen bonds, forming a three-dimensional network. There are also weak C-H⋯π inter-actions present.

Related literature

For structural functions and coordination relationships of aryl­carboxyl­ate ions in transition metal complexes of benzoic acid derivatives, see: Nadzhafov et al. (1981 ▶); Shnulin et al. (1981 ▶). For applications of transition metal complexes with biochemical mol­ecules in biological systems, see: Antolini et al. (1982 ▶). Some benzoic acid derivatives, such as 4-amino­benzoic acid, have been extensively reported in coordination chemistry, as bifunctional organic ligands, due to the variety of their coordination modes, see: Chen & Chen (2002 ▶); Amiraslanov et al. (1979 ▶); Hauptmann et al. (2000 ▶). For a related structure involving 4-formyl­benzoate, see: Hökelek et al. (2009 ▶). For bond-length data, see: Allen et al. (1987 ▶).

Experimental

Crystal data

[Cu(C8H5O3)2(C4H4N2)(H2O)2]

M = 477.90

Monoclinic,

a = 21.7514 (4) Å

b = 6.8794 (2) Å

c = 12.9048 (3) Å

β = 93.621 (3)°

V = 1927.17 (8) Å3

Z = 4

Mo Kα radiation

μ = 1.19 mm−1

T = 294 K

0.42 × 0.22 × 0.13 mm

Data collection

Bruker SMART BREEZE CCD diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2012 ▶) T min = 0.738, T max = 0.857

14917 measured reflections

2398 independent reflections

2231 reflections with I > 2σ(I)

R int = 0.029

Refinement

R[F 2 > 2σ(F 2)] = 0.028

wR(F 2) = 0.089

S = 1.14

2398 reflections

150 parameters

2 restraints

H atoms treated by a mixture of independent and constrained refinement

Δρmax = 0.47 e Å−3

Δρmin = −0.30 e Å−3

Data collection: APEX2 (Bruker, 2012 ▶); cell refinement: SAINT (Bruker, 2012 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▶); software used to prepare material for publication: WinGX (Farrugia, 2012 ▶) and PLATON (Spek, 2009 ▶).

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536813032297/su2669sup1.cif

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813032297/su2669Isup2.hkl

Additional supporting information: crystallographic information; 3D view; checkCIF report

[Cu(C8H5O3)2(C4H4N2)(H2O)2]	F(000) = 980
Mr = 477.90	Dx = 1.647 Mg m−3
Monoclinic, C2/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -C 2yc	Cell parameters from 9971 reflections
a = 21.7514 (4) Å	θ = 2.4–28.4°
b = 6.8794 (2) Å	µ = 1.19 mm−1
c = 12.9048 (3) Å	T = 294 K
β = 93.621 (3)°	Block, blue
V = 1927.17 (8) Å3	0.42 × 0.22 × 0.13 mm
Z = 4

Bruker SMART BREEZE CCD diffractometer	2398 independent reflections
Radiation source: fine-focus sealed tube	2231 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.029
φ and ω scans	θmax = 28.4°, θmin = 1.9°
Absorption correction: multi-scan (SADABS; Bruker, 2012)	h = −28→27
Tmin = 0.738, Tmax = 0.857	k = −8→9
14917 measured reflections	l = −17→17

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)] = 0.028	Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.089	H atoms treated by a mixture of independent and constrained refinement
S = 1.14	w = 1/[σ2(Fo2) + (0.0478P)2 + 1.6638P] where P = (Fo2 + 2Fc2)/3
2398 reflections	(Δ/σ)max = 0.001
150 parameters	Δρmax = 0.47 e Å−3
2 restraints	Δρmin = −0.30 e Å−3

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 esds are taken into account in the estimation of distances, angles and torsion angles

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 > 2sigma(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	0.50000	0.56167 (4)	0.25000	0.0226 (1)
O1	0.58159 (6)	0.55545 (17)	0.19469 (11)	0.0283 (3)
O2	0.63771 (7)	0.6755 (3)	0.33131 (11)	0.0478 (5)
O3	0.90018 (8)	0.6186 (4)	0.03875 (15)	0.0643 (7)
O4	0.54054 (7)	0.5818 (3)	0.43338 (12)	0.0429 (5)
N1	0.50000	0.8590 (3)	0.25000	0.0222 (5)
N2	0.50000	1.2632 (3)	0.25000	0.0228 (5)
C1	0.63185 (7)	0.6123 (2)	0.24173 (13)	0.0255 (4)
C2	0.68848 (7)	0.5984 (2)	0.18010 (13)	0.0233 (4)
C3	0.68624 (8)	0.5098 (3)	0.08295 (13)	0.0278 (4)
C4	0.73941 (8)	0.4934 (3)	0.02948 (13)	0.0311 (5)
C5	0.79501 (8)	0.5656 (3)	0.07299 (15)	0.0298 (5)
C6	0.79729 (8)	0.6554 (3)	0.16972 (14)	0.0322 (5)
C7	0.74435 (8)	0.6718 (3)	0.22284 (13)	0.0286 (5)
C8	0.85122 (10)	0.5472 (3)	0.01458 (19)	0.0433 (7)
C9	0.52244 (8)	0.9602 (2)	0.17228 (13)	0.0263 (5)
C10	0.52268 (8)	1.1618 (2)	0.17257 (13)	0.0265 (5)
H3	0.64910	0.46150	0.05390	0.0330*
H4	0.73790	0.43420	−0.03540	0.0370*
H6	0.83440	0.70420	0.19860	0.0390*
H7	0.74590	0.73200	0.28750	0.0340*
H8	0.84820	0.47380	−0.04600	0.0520*
H9	0.53820	0.89410	0.11700	0.0310*
H10	0.53900	1.22800	0.11770	0.0320*
H41	0.5464 (15)	0.485 (3)	0.465 (2)	0.065 (10)*
H42	0.5738 (10)	0.609 (5)	0.414 (2)	0.064 (9)*

	U11	U22	U33	U12	U13	U23
Cu1	0.0165 (2)	0.0139 (2)	0.0382 (2)	0.0000	0.0076 (1)	0.0000
O1	0.0170 (5)	0.0258 (6)	0.0428 (7)	−0.0016 (4)	0.0076 (5)	−0.0036 (5)
O2	0.0327 (7)	0.0712 (11)	0.0413 (8)	−0.0153 (7)	0.0155 (6)	−0.0173 (7)
O3	0.0307 (8)	0.0990 (15)	0.0650 (11)	−0.0003 (9)	0.0176 (7)	0.0074 (11)
O4	0.0330 (8)	0.0558 (10)	0.0408 (8)	−0.0057 (7)	0.0086 (6)	0.0119 (7)
N1	0.0214 (8)	0.0149 (9)	0.0308 (9)	0.0000	0.0065 (7)	0.0000
N2	0.0206 (8)	0.0160 (8)	0.0322 (9)	0.0000	0.0055 (7)	0.0000
C1	0.0211 (7)	0.0212 (7)	0.0350 (8)	−0.0011 (6)	0.0079 (6)	0.0000 (6)
C2	0.0186 (7)	0.0219 (7)	0.0298 (8)	0.0006 (6)	0.0046 (6)	0.0021 (6)
C3	0.0215 (7)	0.0302 (8)	0.0316 (8)	−0.0002 (6)	0.0002 (6)	−0.0008 (7)
C4	0.0312 (9)	0.0340 (9)	0.0284 (8)	0.0045 (7)	0.0045 (7)	−0.0018 (7)
C5	0.0236 (8)	0.0307 (9)	0.0359 (9)	0.0038 (6)	0.0093 (7)	0.0044 (7)
C6	0.0204 (7)	0.0372 (10)	0.0391 (9)	−0.0049 (7)	0.0032 (6)	0.0000 (8)
C7	0.0245 (8)	0.0312 (9)	0.0305 (8)	−0.0054 (7)	0.0044 (6)	−0.0046 (7)
C8	0.0317 (10)	0.0525 (14)	0.0475 (11)	0.0065 (8)	0.0170 (9)	0.0027 (9)
C9	0.0301 (8)	0.0206 (8)	0.0293 (8)	0.0001 (6)	0.0114 (6)	−0.0016 (6)
C10	0.0298 (8)	0.0200 (8)	0.0308 (8)	0.0006 (6)	0.0111 (6)	0.0029 (6)

Cu1—O1	1.9547 (13)	C2—C3	1.392 (2)
Cu1—O4	2.4766 (15)	C2—C7	1.397 (2)
Cu1—N1	2.046 (2)	C3—C4	1.388 (2)
Cu1—N2i	2.053 (2)	C4—C5	1.392 (3)
Cu1—O1ii	1.9547 (13)	C5—C6	1.391 (3)
Cu1—O4ii	2.4766 (15)	C5—C8	1.482 (3)
O1—C1	1.278 (2)	C6—C7	1.381 (2)
O2—C1	1.234 (2)	C9—C10	1.3869 (19)
O3—C8	1.196 (3)	C3—H3	0.9300
O4—H42	0.80 (2)	C4—H4	0.9300
O4—H41	0.79 (2)	C6—H6	0.9300
N1—C9ii	1.3382 (19)	C7—H7	0.9300
N1—C9	1.3382 (19)	C8—H8	0.9300
N2—C10	1.3382 (19)	C9—H9	0.9300
N2—C10ii	1.3382 (19)	C10—H10	0.9300
C1—C2	1.511 (2)
O1—Cu1—O4	94.21 (5)	C3—C2—C7	119.60 (15)
O1—Cu1—N1	91.25 (4)	C1—C2—C7	119.15 (14)
O1—Cu1—N2i	88.75 (4)	C1—C2—C3	121.23 (14)
O1—Cu1—O1ii	177.49 (5)	C2—C3—C4	120.02 (16)
O1—Cu1—O4ii	85.93 (5)	C3—C4—C5	120.01 (16)
O4—Cu1—N1	86.80 (5)	C4—C5—C6	120.08 (16)
O4—Cu1—N2i	93.21 (5)	C4—C5—C8	119.21 (18)
O1ii—Cu1—O4	85.93 (5)	C6—C5—C8	120.71 (17)
O4—Cu1—O4ii	173.59 (7)	C5—C6—C7	119.87 (17)
N1—Cu1—N2i	180.00	C2—C7—C6	120.41 (16)
O1ii—Cu1—N1	91.25 (4)	O3—C8—C5	125.6 (2)
O4ii—Cu1—N1	86.80 (5)	N1—C9—C10	121.31 (16)
O1ii—Cu1—N2i	88.75 (4)	N2—C10—C9	121.45 (16)
O4ii—Cu1—N2i	93.21 (5)	C2—C3—H3	120.00
O1ii—Cu1—O4ii	94.21 (5)	C4—C3—H3	120.00
Cu1—O1—C1	126.09 (12)	C3—C4—H4	120.00
Cu1—O4—H41	119.0 (18)	C5—C4—H4	120.00
Cu1—O4—H42	89.4 (18)	C5—C6—H6	120.00
H41—O4—H42	104 (3)	C7—C6—H6	120.00
C9—N1—C9ii	117.30 (18)	C2—C7—H7	120.00
Cu1—N1—C9	121.35 (10)	C6—C7—H7	120.00
Cu1—N1—C9ii	121.35 (10)	O3—C8—H8	117.00
Cu1iii—N2—C10	121.42 (10)	C5—C8—H8	117.00
C10—N2—C10ii	117.16 (18)	N1—C9—H9	119.00
Cu1iii—N2—C10ii	121.42 (10)	C10—C9—H9	119.00
O1—C1—O2	125.98 (16)	N2—C10—H10	119.00
O2—C1—C2	118.42 (15)	C9—C10—H10	119.00
O1—C1—C2	115.60 (14)
O4—Cu1—O1—C1	−20.13 (13)	O1—C1—C2—C7	174.99 (15)
N1—Cu1—O1—C1	66.75 (12)	O2—C1—C2—C3	173.20 (18)
N2i—Cu1—O1—C1	−113.26 (12)	O2—C1—C2—C7	−5.2 (2)
O4ii—Cu1—O1—C1	153.44 (13)	C1—C2—C3—C4	−177.90 (16)
O1—Cu1—N1—C9	39.77 (10)	C7—C2—C3—C4	0.5 (3)
O1—Cu1—N1—C9ii	−140.23 (10)	C1—C2—C7—C6	177.88 (16)
O4—Cu1—N1—C9	133.92 (9)	C3—C2—C7—C6	−0.6 (3)
O4—Cu1—N1—C9ii	−46.08 (9)	C2—C3—C4—C5	0.0 (3)
O1ii—Cu1—N1—C9	−140.23 (10)	C3—C4—C5—C6	−0.4 (3)
O4ii—Cu1—N1—C9	−46.08 (9)	C3—C4—C5—C8	−179.83 (19)
Cu1—O1—C1—O2	2.3 (2)	C4—C5—C6—C7	0.4 (3)
Cu1—O1—C1—C2	−177.93 (9)	C8—C5—C6—C7	179.77 (19)
Cu1—N1—C9—C10	−179.70 (12)	C4—C5—C8—O3	172.6 (2)
C9ii—N1—C9—C10	0.3 (2)	C6—C5—C8—O3	−6.8 (4)
Cu1iii—N2—C10—C9	−179.70 (12)	C5—C6—C7—C2	0.1 (3)
C10ii—N2—C10—C9	0.3 (2)	N1—C9—C10—N2	−0.6 (2)
O1—C1—C2—C3	−6.6 (2)

D—H···A	D—H	H···A	D···A	D—H···A
O4—H42···O2	0.80 (2)	1.86 (2)	2.640 (2)	163 (3)
O4—H41···O4iv	0.79 (2)	2.41 (3)	2.778 (2)	110 (3)
C9—H9···O3v	0.93	2.49	3.335 (3)	152
C7—H7···Cgvi	0.93	2.66	3.433 (2)	141

Table 1

Hydrogen-bond geometry (Å, °)

Cg is the centroid of the C2–C7 ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O4—H42⋯O2	0.80 (2)	1.86 (2)	2.640 (2)	163 (3)
O4—H41⋯O4i	0.79 (2)	2.41 (3)	2.778 (2)	110 (3)
C9—H9⋯O3ii	0.93	2.49	3.335 (3)	152
C7—H7⋯Cg iii	0.93	2.66	3.433 (2)	141

Symmetry codes: (i) ; (ii) ; (iii) .