Poly[[diaqua­bis(μ3-maleato-κ4O1:O1′,O4:O4′)dicopper(II)] trihydrate]

Farnum, G.A.; LaDuca, R.L.

doi:10.1107/S1600536808023131

metal-organic compounds

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ISSN: 2056-9890

Volume 64| Part 8| August 2008| Page m1074

doi:10.1107/S1600536808023131

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Poly[[diaquabis(μ₃-maleato-κ⁴O¹:O^1′,O⁴:O^4′)dicopper(II)] trihydrate]

Gregory A. Farnum ^a and Robert L. LaDuca ^a ^*

^aLyman Briggs College, Department of Chemistry, Michigan State University, East Lansing, MI 48825, USA
^*Correspondence e-mail: laduca@msu.edu

(Received 21 July 2008; accepted 22 July 2008; online 26 July 2008)

In the title compound, {[Cu₂(C₄H₂O₄)₂(H₂O)₂]·3H₂O}_n, Cu^II ions with square-pyramidal coordination are bridged by exotridentate maleate dianions into [Cu₂(maleate)₂(H₂O)₂]_n layers coincident with the bc crystal plane. The interlamellar regions contain hydrogen-bonded cyclic water hexamers which facilitate layer stacking into a pseudo-three-dimensional crystal structure. The water hexamers themselves are formed by the operation of crystallographic inversion centers on sets of three crystallographically distinct water molecules of hydration.

Related literature

For recent dpa coordination polymers, see: Brown et al. (2008 ). For the preparation of dpa, see: Zapf et al. (1998 ). For the determination of the τ factor for five-coordinate geometries, see: Addison et al. (1984 ).

Experimental

Crystal data

[Cu₂(C₄H₂O₄)₂(H₂O)₂]·3H₂O
M_r = 445.27
Monoclinic, P 2₁ /c
a = 8.8835 (14) Å
b = 8.7700 (14) Å
c = 18.814 (3) Å
β = 97.994 (3)°
V = 1451.5 (4) Å³
Z = 4
Mo Kα radiation
μ = 3.00 mm⁻¹
T = 173 (2) K
0.30 × 0.28 × 0.05 mm

Data collection

Bruker APEXII diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ) T_min = 0.470, T_max = 0.860
9585 measured reflections
2643 independent reflections
2331 reflections with I > 2σ(I)
R_int = 0.026

Refinement

R[F² > 2σ(F²)] = 0.023
wR(F²) = 0.055
S = 1.03
2643 reflections
238 parameters
15 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.31 e Å⁻³
Δρ_min = −0.31 e Å⁻³

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1W—H1WA⋯O5	0.878 (16)	2.034 (17)	2.910 (3)	175 (3)
O1W—H1WB⋯O2W	0.864 (16)	2.034 (18)	2.863 (3)	161 (3)
O2W—H2WA⋯O7	0.861 (16)	1.967 (17)	2.827 (3)	177 (3)
O2W—H2WB⋯O3W	0.851 (16)	2.014 (18)	2.854 (3)	169 (3)
O3W—H3WA⋯O2ⁱ	0.871 (16)	1.995 (19)	2.847 (2)	166 (3)
O3W—H3WB⋯O1Wⁱ	0.857 (16)	2.17 (2)	2.928 (3)	148 (2)
O9—H9A⋯O1Wⁱⁱ	0.853 (16)	1.987 (18)	2.831 (3)	170 (3)
O9—H9B⋯O10ⁱⁱⁱ	0.851 (16)	2.023 (19)	2.855 (3)	165 (2)
O10—H10A⋯O2W^iv	0.867 (16)	1.943 (17)	2.797 (3)	168 (3)
O10—H10B⋯O3W	0.846 (16)	2.059 (18)	2.879 (3)	163 (2)
Symmetry codes: (i) -x+1, -y+1, -z; (ii) -x+2, -y+1, -z; (iii) x+1, y+1, z; (iv) -x+1, -y, -z.

Data collection: COSMO (Bruker, 2006 ); cell refinement: APEX2 (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalMaker (Palmer, 2007 ); software used to prepare material for publication: SHELXL97.

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808023131/sj2520sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808023131/sj2520Isup2.hkl

checkCIF report

Comment top

Recently our group has been investigating metal dicarboxylate coordination polymers with 4,4'-dipyridylamine (dpa) co-ligands (Brown et al., 2008). In an attempt to prepare a copper maleate/dpa dual-ligand coordination polymer, blue plates of the title compound were obtained. The asymmetric unit (Fig. 1) of the title compound contains two Cu^II ions, two maleate ligands and two aqua ligands along with three water molecules of crystallization. Each crystallographically distinct Cu^II ion manifests square pyramidal [CuO₅] coordination with τ factors (Addison et al., 1984) of 0.045 and 0.025 for Cu1 and Cu2, respectively.

Each Cu1 atom is connected to two Cu2 atoms by a exotridentate maleate ligand. In turn, each Cu2 atom is connected to two Cu1 atoms by a crystallographically distinct exotridentate maleate ligand. In this manner [Cu₂(maleate)₂(H₂O)₂]_n layers are constructed, coincident with the bc crystal planes (Fig. 2). The Cu atoms describe a (4,4) grid with Cu···Cu distances around the grid perimeter of 4.925 (1), 4.874 (1), 4.902 (1) and 4.835 (1) Å. The through-space Cu···Cu distances across the two different types of grid spaces measure 6.338 (1) and 6.261 (1) Å, and 5.390 and 7.094 Å.

Adjacent [Cu₂(maleate)₂(H₂O)₂]_n layers stack in an ABAB pattern to construct the three-dimensional crystal structure (Fig. 3) by means of O—H···O hydrogen bonding patterns between bound and unligated water molecules of crystallization. The unligated water molecules situated between the [Cu₂(maleate)₂(H₂O)₂]_n layers aggregate into pseudo co-planar cyclic hexamers by action of the crystallographic inversion centers on sets of three crystallographically distinct water molecules of hydration (Fig. 4).

Related literature top

For related literature, see: Addison et al. (1984); Brown et al. (2008); Zapf et al. (1998).

Experimental top

Copper nitrate trihydrate and maleic acid were obtained commercially. 4,4'-dipyridylamine (dpa) was prepared via a published procedure (Zapf et al., 1998). Copper nitrate trihydrate (17 mg, 0.07 mmol) and maleic acid (9 mg, 0.08 mmol) were dissolved in 1.5 ml water in a glass vial. A 0.75 ml aliquot of a 1:1 water:ethanol mixture was then added, followed by 1.5 ml of an ethanolic solution of dpa (32 mg, 0.19 mmol). Blue plates of the title compound deposited after standing at 25 °C for one week.

Computing details top

Data collection: COSMO (Bruker, 2006); cell refinement: APEX2 (Bruker, 2006); data reduction: SAINT (Bruker, 2006); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: CrystalMaker (Palmer, 2007); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures top

	Fig. 1. Asymmetric unit of the title compound, showing 50% probability ellipsoids and atom numbering scheme. Hydrogen atoms have been omitted. Color codes: blue Cu, red O within maleate moieties, orange O within water molecules, black C.
	Fig. 2. A single coordination polymer layer in the title compound, viewed down the c crystal direction.
	Fig. 3. Packing diagram illustrating the ABAB layer stacking pattern, which forms the 3-D crystal structure of the title compound through hydrogen bonding between ligated and unligated water molecules.
	Fig. 4. A single pseudo-planar cyclic water molecule hexamer in the title compound.

Poly[[diaquabis(µ₃-maleato-κ⁴O¹:O^1',O⁴:O^4')dicopper(II)] trihydrate] top

Crystal data top

[Cu₂(C₄H₂O₄)(H₂O)₂]·3H₂O	F(000) = 896
M_r = 445.27	D_x = 2.038 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
a = 8.8835 (14) Å	Cell parameters from 9585 reflections
b = 8.7700 (14) Å	θ = 2.2–25.3°
c = 18.814 (3) Å	µ = 3.00 mm⁻¹
β = 97.994 (3)°	T = 173 K
V = 1451.5 (4) Å³	Plate, blue
Z = 4	0.30 × 0.28 × 0.05 mm

Data collection top

Bruker APEXII diffractometer	2643 independent reflections
Radiation source: fine-focus sealed tube	2331 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.026
ω/ψ scans	θ_max = 25.3°, θ_min = 2.2°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −7→10
T_min = 0.471, T_max = 0.860	k = −10→10
9585 measured reflections	l = −22→21

Refinement top

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)] = 0.023	Hydrogen site location: inferred from neighbouring sites
wR(F²) = 0.055	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	w = 1/[σ²(F_o²) + (0.0212P)² + 1.6998P] where P = (F_o² + 2F_c²)/3
2643 reflections	(Δ/σ)_max = 0.001
238 parameters	Δρ_max = 0.31 e Å⁻³
15 restraints	Δρ_min = −0.31 e Å⁻³

Crystal data top

[Cu₂(C₄H₂O₄)(H₂O)₂]·3H₂O	V = 1451.5 (4) Å³
M_r = 445.27	Z = 4
Monoclinic, P2₁/c	Mo Kα radiation
a = 8.8835 (14) Å	µ = 3.00 mm⁻¹
b = 8.7700 (14) Å	T = 173 K
c = 18.814 (3) Å	0.30 × 0.28 × 0.05 mm
β = 97.994 (3)°

Data collection top

Bruker APEXII diffractometer	2643 independent reflections
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	2331 reflections with I > 2σ(I)
T_min = 0.471, T_max = 0.860	R_int = 0.026
9585 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.023	15 restraints
wR(F²) = 0.055	H atoms treated by a mixture of independent and constrained refinement
S = 1.03	Δρ_max = 0.31 e Å⁻³
2643 reflections	Δρ_min = −0.31 e Å⁻³
238 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

	x	y	z	U_iso*/U_eq
Cu1	1.01597 (3)	0.64409 (3)	0.197428 (15)	0.01156 (9)
Cu2	0.45106 (3)	0.07186 (3)	0.195099 (15)	0.01174 (9)
O1	0.72160 (19)	0.60380 (19)	0.25258 (8)	0.0151 (4)
O1W	0.8228 (2)	0.4259 (2)	0.00615 (10)	0.0233 (4)
H1WA	0.886 (3)	0.433 (3)	0.0464 (12)	0.028*
H1WB	0.746 (2)	0.374 (3)	0.0165 (14)	0.028*
O2	0.80468 (19)	0.6770 (2)	0.15230 (9)	0.0156 (4)
O2W	0.5879 (2)	0.2061 (2)	0.01524 (10)	0.0225 (4)
H2WA	0.605 (3)	0.157 (3)	0.0552 (11)	0.027*
H2WB	0.495 (2)	0.233 (3)	0.0091 (14)	0.027*
O3	0.4171 (2)	0.27085 (19)	0.14892 (9)	0.0164 (4)
O3W	0.2668 (2)	0.2526 (2)	−0.00371 (10)	0.0236 (4)
H3WA	0.238 (3)	0.258 (3)	−0.0498 (9)	0.028*
H3WB	0.242 (3)	0.338 (2)	0.0134 (13)	0.028*
O4	0.5053 (2)	0.38423 (19)	0.25143 (9)	0.0150 (4)
O5	1.0151 (2)	0.44986 (19)	0.14409 (9)	0.0152 (4)
O6	0.9918 (2)	0.32879 (19)	0.24548 (9)	0.0148 (4)
O7	0.63415 (19)	0.0476 (2)	0.14736 (9)	0.0152 (4)
O8	0.78378 (19)	0.09818 (19)	0.24870 (9)	0.0151 (4)
O9	1.0870 (2)	0.7605 (2)	0.10332 (9)	0.0191 (4)
H9A	1.103 (3)	0.701 (3)	0.0691 (12)	0.023*
H9B	1.149 (3)	0.835 (2)	0.1052 (14)	0.023*
O10	0.3104 (2)	−0.0132 (2)	0.08656 (9)	0.0162 (4)
H10A	0.355 (3)	−0.071 (2)	0.0582 (13)	0.019*
H10B	0.280 (3)	0.066 (2)	0.0636 (13)	0.019*
C1	0.6980 (3)	0.6406 (3)	0.18741 (13)	0.0132 (5)
C2	0.5430 (3)	0.6438 (3)	0.14606 (13)	0.0129 (5)
H2	0.5162	0.7317	0.1176	0.016*
C3	0.4383 (3)	0.5354 (3)	0.14503 (13)	0.0140 (5)
H3	0.3437	0.5533	0.1160	0.017*
C4	0.4550 (3)	0.3888 (3)	0.18500 (13)	0.0143 (5)
C5	1.0001 (3)	0.3283 (3)	0.17929 (13)	0.0131 (5)
C6	0.9934 (3)	0.1841 (3)	0.13696 (13)	0.0135 (5)
H6	1.0682	0.1703	0.1060	0.016*
C7	0.8919 (3)	0.0730 (3)	0.13873 (13)	0.0142 (5)
H7	0.9019	−0.0140	0.1097	0.017*
C8	0.7639 (3)	0.0732 (3)	0.18235 (13)	0.0133 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cu1	0.01167 (17)	0.01221 (16)	0.01043 (16)	−0.00015 (13)	0.00021 (12)	−0.00049 (12)
Cu2	0.01275 (18)	0.01194 (16)	0.01041 (16)	−0.00027 (13)	0.00118 (12)	−0.00011 (12)
O1	0.0139 (10)	0.0193 (9)	0.0121 (9)	−0.0001 (8)	0.0017 (7)	0.0033 (7)
O1W	0.0287 (12)	0.0259 (11)	0.0142 (10)	−0.0018 (9)	−0.0006 (8)	0.0005 (9)
O2	0.0113 (9)	0.0225 (10)	0.0129 (9)	−0.0018 (8)	0.0013 (7)	0.0026 (7)
O2W	0.0208 (11)	0.0305 (11)	0.0160 (10)	0.0059 (9)	0.0017 (8)	0.0050 (9)
O3	0.0251 (11)	0.0108 (9)	0.0127 (9)	−0.0018 (8)	0.0007 (7)	−0.0023 (7)
O3W	0.0308 (12)	0.0228 (10)	0.0156 (10)	0.0031 (9)	−0.0026 (9)	−0.0006 (8)
O4	0.0192 (10)	0.0127 (9)	0.0125 (9)	−0.0007 (8)	0.0004 (7)	0.0007 (7)
O5	0.0186 (10)	0.0116 (9)	0.0148 (9)	−0.0017 (8)	−0.0002 (7)	0.0018 (7)
O6	0.0191 (10)	0.0121 (9)	0.0133 (9)	−0.0004 (7)	0.0024 (7)	0.0009 (7)
O7	0.0086 (9)	0.0219 (10)	0.0143 (9)	−0.0009 (8)	−0.0008 (7)	0.0002 (8)
O8	0.0127 (10)	0.0190 (9)	0.0136 (9)	−0.0008 (8)	0.0013 (7)	−0.0008 (7)
O9	0.0230 (11)	0.0158 (10)	0.0203 (10)	−0.0052 (8)	0.0096 (8)	−0.0013 (8)
O10	0.0181 (10)	0.0148 (10)	0.0160 (10)	0.0018 (8)	0.0031 (8)	−0.0004 (8)
C1	0.0158 (14)	0.0088 (12)	0.0149 (13)	0.0013 (11)	0.0019 (11)	−0.0024 (10)
C2	0.0149 (14)	0.0131 (13)	0.0108 (12)	0.0026 (11)	0.0018 (10)	0.0013 (10)
C3	0.0141 (14)	0.0157 (13)	0.0114 (12)	0.0058 (11)	−0.0005 (10)	−0.0007 (10)
C4	0.0089 (13)	0.0168 (13)	0.0180 (14)	0.0003 (11)	0.0050 (10)	0.0002 (11)
C5	0.0075 (13)	0.0148 (13)	0.0162 (14)	0.0011 (10)	−0.0013 (10)	−0.0003 (11)
C6	0.0124 (13)	0.0133 (13)	0.0156 (13)	0.0034 (11)	0.0046 (10)	0.0009 (10)
C7	0.0159 (14)	0.0122 (12)	0.0144 (13)	0.0045 (11)	0.0021 (10)	−0.0002 (10)
C8	0.0167 (14)	0.0074 (12)	0.0157 (13)	0.0017 (11)	0.0018 (11)	0.0012 (10)

Geometric parameters (Å, º) top

Cu1—O6ⁱ	1.9501 (17)	O4—Cu2ⁱⁱⁱ	1.9395 (17)
Cu1—O8ⁱ	1.9628 (17)	O5—C5	1.272 (3)
Cu1—O2	1.9708 (17)	O6—C5	1.258 (3)
Cu1—O5	1.9765 (17)	O6—Cu1^iv	1.9501 (17)
Cu1—O9	2.2101 (17)	O7—C8	1.265 (3)
Cu2—O4ⁱⁱ	1.9395 (17)	O8—C8	1.255 (3)
Cu2—O3	1.9541 (17)	O8—Cu1^iv	1.9627 (17)
Cu2—O1ⁱⁱ	1.9544 (17)	O9—H9A	0.853 (16)
Cu2—O7	1.9757 (17)	O9—H9B	0.851 (16)
Cu2—O10	2.3618 (18)	O10—H10A	0.867 (16)
O1—C1	1.257 (3)	O10—H10B	0.846 (16)
O1—Cu2ⁱⁱⁱ	1.9544 (17)	C1—C2	1.485 (3)
O1W—H1WA	0.878 (16)	C2—C3	1.328 (4)
O1W—H1WB	0.864 (16)	C2—H2	0.9500
O2—C1	1.269 (3)	C3—C4	1.487 (3)
O2W—H2WA	0.861 (16)	C3—H3	0.9500
O2W—H2WB	0.851 (16)	C5—C6	1.492 (3)
O3—C4	1.257 (3)	C6—C7	1.331 (4)
O3W—H3WA	0.871 (16)	C6—H6	0.9500
O3W—H3WB	0.857 (16)	C7—C8	1.492 (3)
O4—C4	1.268 (3)	C7—H7	0.9500

O6ⁱ—Cu1—O8ⁱ	89.13 (7)	Cu1—O9—H9A	114.8 (18)
O6ⁱ—Cu1—O2	90.64 (7)	Cu1—O9—H9B	125.1 (18)
O8ⁱ—Cu1—O2	173.22 (7)	H9A—O9—H9B	109 (2)
O6ⁱ—Cu1—O5	176.01 (7)	Cu2—O10—H10A	118.9 (19)
O8ⁱ—Cu1—O5	91.41 (7)	Cu2—O10—H10B	105.9 (18)
O2—Cu1—O5	88.35 (7)	H10A—O10—H10B	108 (2)
O6ⁱ—Cu1—O9	95.37 (7)	O1—C1—O2	122.5 (2)
O8ⁱ—Cu1—O9	99.75 (7)	O1—C1—C2	122.2 (2)
O2—Cu1—O9	87.02 (7)	O2—C1—C2	115.3 (2)
O5—Cu1—O9	88.44 (7)	C3—C2—C1	126.2 (2)
O4ⁱⁱ—Cu2—O3	174.68 (7)	C3—C2—H2	116.9
O4ⁱⁱ—Cu2—O1ⁱⁱ	88.55 (7)	C1—C2—H2	116.9
O3—Cu2—O1ⁱⁱ	90.71 (7)	C2—C3—C4	126.3 (2)
O4ⁱⁱ—Cu2—O7	91.53 (7)	C2—C3—H3	116.9
O3—Cu2—O7	88.85 (7)	C4—C3—H3	116.9
O1ⁱⁱ—Cu2—O7	176.09 (7)	O3—C4—O4	122.5 (2)
O4ⁱⁱ—Cu2—O10	102.95 (7)	O3—C4—C3	116.0 (2)
O3—Cu2—O10	82.37 (7)	O4—C4—C3	121.5 (2)
O1ⁱⁱ—Cu2—O10	97.06 (7)	O6—C5—O5	122.5 (2)
O7—Cu2—O10	86.73 (7)	O6—C5—C6	121.9 (2)
C1—O1—Cu2ⁱⁱⁱ	119.48 (16)	O5—C5—C6	115.6 (2)
H1WA—O1W—H1WB	106 (2)	C7—C6—C5	125.7 (2)
C1—O2—Cu1	118.31 (16)	C7—C6—H6	117.1
H2WA—O2W—H2WB	108 (2)	C5—C6—H6	117.1
C4—O3—Cu2	118.78 (16)	C6—C7—C8	125.7 (2)
H3WA—O3W—H3WB	106 (2)	C6—C7—H7	117.1
C4—O4—Cu2ⁱⁱⁱ	120.15 (16)	C8—C7—H7	117.1
C5—O5—Cu1	116.82 (16)	O8—C8—O7	122.7 (2)
C5—O6—Cu1^iv	123.65 (16)	O8—C8—C7	122.3 (2)
C8—O7—Cu2	119.51 (16)	O7—C8—C7	115.0 (2)
C8—O8—Cu1^iv	122.77 (16)

O6ⁱ—Cu1—O2—C1	−78.93 (18)	O2—C1—C2—C3	132.4 (3)
O8ⁱ—Cu1—O2—C1	9.1 (7)	C1—C2—C3—C4	−0.1 (4)
O5—Cu1—O2—C1	97.21 (18)	Cu2—O3—C4—O4	−4.7 (3)
O9—Cu1—O2—C1	−174.27 (18)	Cu2—O3—C4—C3	174.94 (16)
O4ⁱⁱ—Cu2—O3—C4	−6.9 (9)	Cu2ⁱⁱⁱ—O4—C4—O3	−175.98 (18)
O1ⁱⁱ—Cu2—O3—C4	75.07 (18)	Cu2ⁱⁱⁱ—O4—C4—C3	4.4 (3)
O7—Cu2—O3—C4	−101.05 (18)	C2—C3—C4—O3	−130.6 (3)
O10—Cu2—O3—C4	172.09 (19)	C2—C3—C4—O4	49.0 (4)
O6ⁱ—Cu1—O5—C5	−27.4 (11)	Cu1^iv—O6—C5—O5	−175.24 (17)
O8ⁱ—Cu1—O5—C5	70.43 (17)	Cu1^iv—O6—C5—C6	4.5 (3)
O2—Cu1—O5—C5	−102.78 (17)	Cu1—O5—C5—O6	−2.6 (3)
O9—Cu1—O5—C5	170.15 (18)	Cu1—O5—C5—C6	177.60 (16)
O4ⁱⁱ—Cu2—O7—C8	−74.33 (18)	O6—C5—C6—C7	47.7 (4)
O3—Cu2—O7—C8	100.36 (18)	O5—C5—C6—C7	−132.5 (3)
O1ⁱⁱ—Cu2—O7—C8	16.7 (11)	C5—C6—C7—C8	1.2 (4)
O10—Cu2—O7—C8	−177.22 (18)	Cu1^iv—O8—C8—O7	−178.04 (17)
Cu2ⁱⁱⁱ—O1—C1—O2	173.13 (17)	Cu1^iv—O8—C8—C7	1.3 (3)
Cu2ⁱⁱⁱ—O1—C1—C2	−7.1 (3)	Cu2—O7—C8—O8	7.6 (3)
Cu1—O2—C1—O1	9.6 (3)	Cu2—O7—C8—C7	−171.73 (15)
Cu1—O2—C1—C2	−170.14 (16)	C6—C7—C8—O8	−52.5 (4)
O1—C1—C2—C3	−47.3 (4)	C6—C7—C8—O7	126.8 (3)

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

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1WA···O5	0.88 (2)	2.03 (2)	2.910 (3)	175 (3)
O1W—H1WB···O2W	0.86 (2)	2.03 (2)	2.863 (3)	161 (3)
O2W—H2WA···O7	0.86 (2)	1.97 (2)	2.827 (3)	177 (3)
O2W—H2WB···O3W	0.85 (2)	2.01 (2)	2.854 (3)	169 (3)
O3W—H3WA···O2^v	0.87 (2)	2.00 (2)	2.847 (2)	166 (3)
O3W—H3WB···O1W^v	0.86 (2)	2.17 (2)	2.928 (3)	148 (2)
O9—H9A···O1W^vi	0.85 (2)	1.99 (2)	2.831 (3)	170 (3)
O9—H9B···O10^vii	0.85 (2)	2.02 (2)	2.855 (3)	165 (2)
O10—H10A···O2W^viii	0.87 (2)	1.94 (2)	2.797 (3)	168 (3)
O10—H10B···O3W	0.85 (2)	2.06 (2)	2.879 (3)	163 (2)

Symmetry codes: (v) −x+1, −y+1, −z; (vi) −x+2, −y+1, −z; (vii) x+1, y+1, z; (viii) −x+1, −y, −z.

Experimental details

Crystal data
Chemical formula	[Cu₂(C₄H₂O₄)(H₂O)₂]·3H₂O
M_r	445.27
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	173
a, b, c (Å)	8.8835 (14), 8.7700 (14), 18.814 (3)
β (°)	97.994 (3)
V (Å³)	1451.5 (4)
Z	4
Radiation type	Mo Kα
µ (mm⁻¹)	3.00
Crystal size (mm)	0.30 × 0.28 × 0.05

Data collection
Diffractometer	Bruker APEXII diffractometer
Absorption correction	Multi-scan (SADABS; Sheldrick, 1996)
T_min, T_max	0.471, 0.860
No. of measured, independent and observed [I > 2σ(I)] reflections	9585, 2643, 2331
R_int	0.026
(sin θ/λ)_max (Å⁻¹)	0.602

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.023, 0.055, 1.03
No. of reflections	2643
No. of parameters	238
No. of restraints	15
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	0.31, −0.31

Computer programs: COSMO (Bruker, 2006), APEX2 (Bruker, 2006), SAINT (Bruker, 2006), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), CrystalMaker (Palmer, 2007).

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1WA···O5	0.878 (16)	2.034 (17)	2.910 (3)	175 (3)
O1W—H1WB···O2W	0.864 (16)	2.034 (18)	2.863 (3)	161 (3)
O2W—H2WA···O7	0.861 (16)	1.967 (17)	2.827 (3)	177 (3)
O2W—H2WB···O3W	0.851 (16)	2.014 (18)	2.854 (3)	169 (3)
O3W—H3WA···O2ⁱ	0.871 (16)	1.995 (19)	2.847 (2)	166 (3)
O3W—H3WB···O1Wⁱ	0.857 (16)	2.17 (2)	2.928 (3)	148 (2)
O9—H9A···O1Wⁱⁱ	0.853 (16)	1.987 (18)	2.831 (3)	170 (3)
O9—H9B···O10ⁱⁱⁱ	0.851 (16)	2.023 (19)	2.855 (3)	165 (2)
O10—H10A···O2W^iv	0.867 (16)	1.943 (17)	2.797 (3)	168 (3)
O10—H10B···O3W	0.846 (16)	2.059 (18)	2.879 (3)	163 (2)

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

Acknowledgements

The authors gratefully acknowledge the American Chemical Society Petroleum Research Fund and Michigan State University for funding this work.

References

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