catena-Poly[[[tetra­quazinc(II)]-μ-2,5-dihydroxy­benzene-1,4-diacetato-κ²O¹:O⁴] dihydrate]

The title compound, {[Zn(C₁₀H₈O₆)(H₂O)₄]·2H₂O}_n, is a one-dimensional coordination polymer with 2,5-dihydroxy­benzene-1,4-diacetate acting as bridging ligand. The zigzag chains, extending parallel to [011], are further packed into a three-dimensional network by hydrogen bonds.

Key indicators

• Single-crystal X-ray study
• T = 113 K
• Mean [sigma](C-C) = 0.004 Å
• R factor = 0.032
• wR factor = 0.117
• Data-to-parameter ratio = 14.7

checkCIF/PLATON results

No syntax errors found



Alert level B
PLAT417_ALERT_2_B Short Inter D-H..H-D       H4B    ..  H6A     ..       2.04 Ang.

Alert level C
            Value of measurement temperature given =   113.000
            Value of melting point given =     0.000
PLAT042_ALERT_1_C Calc. and Rep. MoietyFormula Strings Differ ....          ?
PLAT731_ALERT_1_C Bond    Calc     0.86(3), Rep   0.855(10) ......       3.00 su-Ra
              O5   -H5B     1.555   1.555
PLAT731_ALERT_1_C Bond    Calc     0.84(3), Rep   0.836(10) ......       3.00 su-Ra
              O6   -H6A     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.86(3), Rep   0.855(10) ......       3.00 su-Ra
              O5   -H5B     1.555   1.555
PLAT735_ALERT_1_C D-H     Calc     0.84(3), Rep   0.836(10) ......       3.00 su-Ra
              O6   -H6A     1.555   1.555

Alert level G
PLAT860_ALERT_3_G Note: Number of Least-Squares Restraints .......          9

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

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

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S1. Comment

Rigid carboxylato ligands, such as benzene-carboxylic acid, pyridine-carboxylic acid, etc. have been widely utilized to synthesize coordination polymers because they can link metal ions via one carboxyl group or via the aroma rings, leading plentiful varieties of structures (Cano et al., 1997; Sun et al., 2001; Zhao, et al., 2004). In contrast, flexible aroma-carboxylic acid and their complexes are less studied comparing to the rigid ones. (Ren et al., 2008)

In this contribution, a flexible ligand, 2,5-dihydroxy-p-benzenediacetic acid (H₂dba), was selected to construct coordination polymer, and the title complex was obtained under solvothermal conditions.

The Zn(II) ion in the title compound is coordinated by two oxygen atoms from dba anions in the apical sites and four water molecules in the equatorial plane (Fig. 1). The Zn(II) ions are linked through dba dianion forming one-dimensional chain (Fig. 2). Furthermore, the chains are packed into three-dimensional supermolecular moiety by O—H···O H-bonds (Fig. 3).

Related literature

For related structures, see Ren et al. (2008); Cano et al. (1997); Sun et al. (2001); Zhao et al. (2004).

S2. Experimental

A mixture of Zn(Ac)₂2H₂O (0.5 mmol, 109.8 mg), H₂dba (0.5 mmol, 133.0 mg), 10 ml THF and 10 ml water was put into a 25 ml acid digestion bomb and heated at 80°C for three days. After cooling to room temperature, the title compound (56% yield based on Zn(II) salt) was obtained. Elemental analysis (%) for the title compound C₁₀H₂₀ZnO₁₂: found: C, 29.94; H, 4.96; N, 0. Calc.: C, 30.20; H, 5.07; N, 0.

S3. Refinement

The carboxyl H and aromatic H were placed in calculated positions and refined in riding mode with U_iso(H) = 1.2U_eq(C). Water H atoms were located in a difference Fourier map and refined as riding in as-found relative positions with U_iso(H) = 1.5U_eq(O).

Computing details

Data collection: CrystalStructure (Rigaku/MSC, 2005); cell refinement: CrystalStructure (Rigaku/MSC, 2005); data reduction: CrystalStructure (Rigaku/MSC, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: CrystalStructure (Rigaku/MSC, 2005).

Figures

	Fig. 1. The molecular structure of the title compound with 30% probability displacement ellipsoids. Symmetry code: A - x, -y + 2 - z.
	Fig. 2. One-dimensional chain structure of the title compound. H atoms and lattice water molecules are omitted for clarity. Symmetry code: (A) x, y, z; (B) - x, -y + 2 - z; (C) 1 - x, 1 - y, -z.
	Fig. 3. The packing diagram of the title compound.

catena-Poly[[[tetraquazinc(II)]-µ-2,5-dihydroxybenzene-1,4-diacetato- κ²O¹:O⁴] dihydrate]

Crystal data

[Zn(C10H8O6)(H2O)4]·2H2O	F(000) = 412
Mr = 397.63	Dx = 1.835 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P2ybc	Cell parameters from 1803 reflections
a = 11.122 (2) Å	θ = 2.9–28.6°
b = 7.5176 (15) Å	µ = 1.77 mm^−1
c = 8.6417 (17) Å	T = 113 K
β = 95.12 (3)°	Prism, colorless
V = 719.7 (2) Å^3	0.32 × 0.24 × 0.10 mm
Z = 2

Data collection

Rigaku Saturn diffractometer	1833 independent reflections
Radiation source: rotating anode	1405 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.041
ω scans	θmax = 28.6°, θmin = 1.8°
Absorption correction: multi-scan (CrystalStructure; Rigaku/MSC, 2005)	h = −14→14
Tmin = 0.601, Tmax = 0.843	k = −10→10
6863 measured reflections	l = −10→11

Refinement

Refinement on F^2	9 restraints
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.032	w = 1/[σ^2(Fo^2) + (0.0565P)^2 + 0.7652P] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.117	(Δ/σ)max < 0.001
S = 1.17	Δρmax = 0.60 e Å^−3
1833 reflections	Δρmin = −0.66 e Å^−3
125 parameters

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
Zn1	0.5000	0.5000	0.5000	0.00908 (16)
O1	0.33235 (19)	0.5544 (3)	0.5773 (2)	0.0106 (4)
O2	0.30469 (19)	0.8254 (3)	0.4764 (3)	0.0142 (5)
O3	0.17185 (19)	1.0259 (3)	0.7503 (3)	0.0124 (5)
H3	0.1832	1.1332	0.7746	0.019*
O4	0.4629 (2)	0.2263 (3)	0.5260 (3)	0.0121 (4)
H4A	0.5325 (13)	0.207 (5)	0.494 (4)	0.018*
H4B	0.4037 (18)	0.197 (5)	0.460 (3)	0.018*
O5	0.4263 (2)	0.5039 (3)	0.2703 (3)	0.0138 (4)
H5A	0.3500 (11)	0.517 (4)	0.268 (4)	0.021*
H5B	0.449 (3)	0.426 (4)	0.207 (4)	0.021*
C1	0.2689 (3)	0.6913 (4)	0.5470 (3)	0.0103 (6)
C2	0.1445 (3)	0.6927 (4)	0.6029 (4)	0.0107 (6)
H2A	0.1014	0.5838	0.5647	0.013*
H2B	0.1525	0.6879	0.7178	0.013*
C3	0.0690 (2)	0.8511 (4)	0.5524 (3)	0.0090 (6)
C4	−0.0186 (3)	0.8388 (4)	0.4269 (3)	0.0103 (6)
H4	−0.0321	0.7277	0.3758	0.012*
C5	0.0863 (2)	1.0146 (4)	0.6249 (3)	0.0095 (5)
O6	0.2650 (2)	0.3550 (3)	0.8178 (3)	0.0133 (4)
H6A	0.246 (3)	0.426 (4)	0.886 (3)	0.020*
H6B	0.286 (3)	0.395 (4)	0.733 (2)	0.020*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.0073 (2)	0.0100 (3)	0.0101 (3)	0.00122 (18)	0.00169 (16)	0.00064 (19)
O1	0.0082 (10)	0.0111 (10)	0.0125 (10)	0.0037 (8)	0.0015 (8)	0.0024 (8)
O2	0.0097 (10)	0.0127 (10)	0.0204 (12)	0.0011 (8)	0.0035 (9)	0.0034 (9)
O3	0.0108 (10)	0.0131 (11)	0.0125 (11)	−0.0002 (8)	−0.0035 (8)	−0.0011 (8)
O4	0.0086 (9)	0.0104 (10)	0.0177 (11)	0.0004 (8)	0.0032 (8)	0.0010 (8)
O5	0.0111 (10)	0.0182 (11)	0.0117 (11)	0.0018 (9)	−0.0007 (8)	−0.0026 (9)
C1	0.0089 (13)	0.0116 (14)	0.0104 (14)	0.0005 (11)	−0.0001 (11)	−0.0042 (11)
C2	0.0080 (13)	0.0126 (14)	0.0117 (14)	0.0043 (10)	0.0023 (11)	0.0046 (11)
C3	0.0049 (12)	0.0095 (13)	0.0132 (14)	0.0020 (10)	0.0043 (10)	0.0031 (11)
C4	0.0079 (12)	0.0156 (14)	0.0080 (14)	0.0006 (11)	0.0039 (10)	−0.0018 (11)
C5	0.0048 (11)	0.0159 (14)	0.0082 (13)	0.0023 (11)	0.0027 (9)	0.0011 (11)
O6	0.0159 (11)	0.0119 (11)	0.0123 (11)	−0.0003 (8)	0.0028 (9)	0.0001 (8)

Geometric parameters (Å, º)

Zn1—O1	2.077 (2)	O5—H5B	0.855 (10)
Zn1—O1^i	2.077 (2)	C1—C2	1.506 (4)
Zn1—O5^i	2.080 (2)	C2—C3	1.500 (4)
Zn1—O5	2.080 (2)	C2—H2A	0.9900
Zn1—O4	2.115 (2)	C2—H2B	0.9900
Zn1—O4^i	2.115 (2)	C3—C5	1.384 (4)
O1—C1	1.262 (3)	C3—C4	1.395 (4)
O2—C1	1.261 (4)	C4—C5^ii	1.387 (4)
O3—C5	1.379 (3)	C4—H4	0.9500
O3—H3	0.8400	C5—C4^ii	1.387 (4)
O4—H4A	0.857 (10)	O6—H6A	0.836 (10)
O4—H4B	0.859 (10)	O6—H6B	0.843 (10)
O5—H5A	0.853 (10)
O1—Zn1—O1^i	180.0	Zn1—O5—H5B	119 (2)
O1—Zn1—O5^i	89.12 (9)	H5A—O5—H5B	114.9 (18)
O1^i—Zn1—O5^i	90.88 (9)	O2—C1—O1	123.9 (3)
O1—Zn1—O5	90.88 (9)	O2—C1—C2	119.2 (3)
O1^i—Zn1—O5	89.12 (9)	O1—C1—C2	116.8 (3)
O5^i—Zn1—O5	180.0	C3—C2—C1	114.8 (2)
O1—Zn1—O4	88.16 (8)	C3—C2—H2A	108.6
O1^i—Zn1—O4	91.84 (8)	C1—C2—H2A	108.6
O5^i—Zn1—O4	87.08 (8)	C3—C2—H2B	108.6
O5—Zn1—O4	92.92 (9)	C1—C2—H2B	108.6
O1—Zn1—O4^i	91.84 (8)	H2A—C2—H2B	107.6
O1^i—Zn1—O4^i	88.16 (8)	C5—C3—C4	118.1 (3)
O5^i—Zn1—O4^i	92.92 (9)	C5—C3—C2	121.4 (3)
O5—Zn1—O4^i	87.08 (8)	C4—C3—C2	120.5 (3)
O4—Zn1—O4^i	180.0	C5^ii—C4—C3	121.3 (3)
C1—O1—Zn1	126.52 (19)	C5^ii—C4—H4	119.4
C5—O3—H3	109.5	C3—C4—H4	119.4
Zn1—O4—H4A	86 (3)	O3—C5—C3	117.9 (3)
Zn1—O4—H4B	109 (3)	O3—C5—C4^ii	121.4 (3)
H4A—O4—H4B	113.9 (17)	C3—C5—C4^ii	120.7 (3)
Zn1—O5—H5A	109 (3)	H6A—O6—H6B	119.8 (19)
O5^i—Zn1—O1—C1	118.5 (2)	C1—C2—C3—C5	−77.9 (4)
O5—Zn1—O1—C1	−61.5 (2)	C1—C2—C3—C4	100.0 (3)
O4—Zn1—O1—C1	−154.4 (2)	C5—C3—C4—C5^ii	0.2 (5)
O4^i—Zn1—O1—C1	25.6 (2)	C2—C3—C4—C5^ii	−177.7 (3)
Zn1—O1—C1—O2	−7.4 (4)	C4—C3—C5—O3	179.1 (3)
Zn1—O1—C1—C2	173.89 (19)	C2—C3—C5—O3	−2.9 (4)
O2—C1—C2—C3	6.2 (4)	C4—C3—C5—C4^ii	−0.2 (5)
O1—C1—C2—C3	−175.0 (3)	C2—C3—C5—C4^ii	177.7 (3)

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

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O3—H3···O6^iii	0.84	1.92	2.725 (3)	160
O4—H4A···O2^i	0.86 (1)	1.82 (2)	2.616 (3)	153 (3)
O4—H4A···O1^i	0.86 (1)	2.45 (3)	3.011 (3)	123 (3)
O4—H4B···O6^iv	0.86 (1)	1.93 (1)	2.783 (3)	176 (3)
O5—H5A···O3^v	0.85 (1)	2.00 (2)	2.828 (3)	164 (3)
O5—H5B···O4^iv	0.86 (1)	1.96 (2)	2.787 (3)	164 (3)
O6—H6A···O2^vi	0.84 (1)	2.11 (3)	2.781 (3)	137 (3)
O6—H6B···O1	0.84 (1)	1.91 (2)	2.721 (3)	162 (3)

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