Diaqua­bis(3-carboxy­pyridine-2-carboxyl­ato-κ²N,O²)zinc(II)

The centrosymmetric title compound, [Zn(C₁₄H₈N₂O₈)₂(H₂O)₂], shows a distorted octa­hedral coordination. The four donor atoms of the two coplanar 3-carboxy­pyridine-2-carboxyl­ate or (2,3-pydcH)⁻ anions form a square-planar arrangement around the Zn^II centre. This crystal structure has an infinite three-dimensional framework. The stabilizing inter­actions existing in the crystal structure are inter­molecular O—H...O and very strong intra­molecular O—H...O hydrogen bonds. H atoms of coordinated water mol­ecules participate in hydrogen-bonded chains described by C₂²(12) and C₁¹(8) graph-set descriptors.

Key indicators

• Single-crystal X-ray study
• T = 150 K
• Mean [sigma](C-C) = 0.002 Å
• R factor = 0.025
• wR factor = 0.069
• Data-to-parameter ratio = 13.8

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT062_ALERT_4_C Rescale T(min) & T(max) by .....................       0.94
PLAT125_ALERT_4_C No _symmetry_space_group_name_Hall Given .......          ?
PLAT232_ALERT_2_C Hirshfeld Test Diff (M-X)  Zn1    -   N1      ..       5.08 su
PLAT369_ALERT_2_C Long   C(sp2)-C(sp2) Bond  C1     -   C6     ...       1.54 Ang.
PLAT369_ALERT_2_C Long   C(sp2)-C(sp2) Bond  C2     -   C7     ...       1.53 Ang.
PLAT480_ALERT_4_C Long H...A H-Bond Reported H5B    ..  O4      ..       2.64 Ang.

Alert level G
ABSTM02_ALERT_3_G  When printed, the submitted absorption T values will be
            replaced by the scaled T values. Since the ratio of scaled T's
            is identical to the ratio of reported T values, the scaling
            does not imply a change to the absorption corrections used in
            the study.
            Ratio of Tmax expected/reported      0.939
            Tmax scaled      0.552 Tmin scaled      0.530
PLAT794_ALERT_5_G Check Predicted Bond Valency for Zn1         (2)       2.09

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

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 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
   3 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

The lattice consists of [Zn(2,3-pydcH)₂(H₂O)₂] complexes resulted by a doubly monoprotonated (2,3-pydcH)^- as a bidentate ligand. The presence of this bidentate ligand leads to a neutral complex and does not allow the 2,9-dimethyl-1,10-phenanthroline Lewis base to crystallize in the produced network. The asymmetric unit of compound, [Zn(2,3-pydcH)₂(H₂O)₂] is presented in Figure 1. The metal center is hexacoordinated by two (2,3-pydcH)^- bidentate ligand and two water molecules. The geometry around Zn^II center is distorted octahedral. The four donor atoms of the two (2,3-pydcH)^- anions form a square planar arrangement around Zn^II center. The rings are almost coplanar (RMS deviation 0.0057 Å). In construction of this crystal which has an infinite three dimensional framework based on [100], [001] and [010] vectors, the hydrogen bonding intermolecular interactions play the essential role. The stabilizing interactions existing in the crystal lattice are intermolecular O–H···O and very strong intramolecular O–H···O type hydrogen bonds.

Hydrogen atoms of coordinated water molecules participate in hydrogen bonded chains described by C²₂(12) and C¹₁(8) graph set descriptors. Thus, the three-dimensional supramolecule structure for [Zn(2,3-pydcH)₂(H₂O)₂] is confirmed.

Related literature

Several complexes of zinc with pyridine-2,6-dicarboxylic acid have been reported (Aghajani et al., 2006, and references therein). There is also a report of a similar copper compound with pyridine-2,3-dicarboxylic acid in the literature (Xiang et al., 2006).

S2. Experimental

To a 10 ml of a stirring aqueous solution of 2,9-dimethyl-1,10-phenathroline (0.104 g, 0.5 mmol) and pyridine-2,3-dicarboxylic acid (0.0836 g, 0.5 mmol), was added a 0.5 molar equivalent of ZnSO₄ . 7H₂O (0.0727 g, 0.25 mmol) at room temperature. A neutral zinc(II) complex, [Zn(2,3-pydcH)₂(H₂O)₂], was isolated at pH 3.0 as a colorless crystals. Slow evaporation of the solvent during 10 days resulted in product complexes. Recrystallization of resultants for several times leads to X-ray quality crystals.

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SMART; data reduction: SAINT-Plus (Bruker, 1998); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1997); software used to prepare material for publication: SHELXTL.

Figures

	Fig. 1. The asymmetric unit of (I), with displacement ellipsoids drawn at the 50% probability level. The intramolecular hydrogen bonds are shown by dashed lines.
	Fig. 2. Packing diagram of (I) with H-bonds with dashed lines. H atoms not involved in H-bonds omitter for clarity.

Diaquabis(3-carboxypyridine-2-carboxylato-κ²N,O²)zinc(II)

Crystal data

[Zn(C14H8N2O8)(H2O)2]	F(000) = 440
Mr = 433.63	Dx = 1.913 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
a = 9.304 (3) Å	Cell parameters from 5661 reflections
b = 7.909 (3) Å	θ = 2.8–27.5°
c = 10.276 (4) Å	µ = 1.70 mm^−1
β = 95.317 (6)°	T = 150 K
V = 752.9 (5) Å^3	Block, colourless
Z = 2	0.38 × 0.38 × 0.35 mm

Data collection

Bruker SMART diffractometer	1706 independent reflections
Radiation source: fine-focus sealed tube	1575 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.023
Detector resolution: 100 pixels mm^-1	θmax = 27.5°, θmin = 2.8°
ω scans	h = −11→11
Absorption correction: multi-scan (SADABS; Sheldrick, 1998)	k = −10→10
Tmin = 0.565, Tmax = 0.588	l = −13→13
8225 measured reflections

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)] = 0.025	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.069	H-atom parameters constrained
S = 1.12	w = 1/[σ^2(Fo^2) + (0.0383P)^2 + 0.3534P] where P = (Fo^2 + 2Fc^2)/3
1706 reflections	(Δ/σ)max = 0.001
124 parameters	Δρmax = 0.40 e Å^−3
0 restraints	Δρmin = −0.40 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
Zn1	0.5000	0.5000	1.0000	0.01651 (11)
N1	0.66631 (13)	0.66168 (17)	0.96316 (12)	0.0159 (3)
C1	0.77906 (16)	0.59130 (19)	0.90988 (14)	0.0147 (3)
C2	0.89688 (16)	0.6908 (2)	0.88011 (14)	0.0156 (3)
C3	0.88952 (17)	0.8644 (2)	0.90586 (15)	0.0189 (3)
H3	0.9665	0.9356	0.8855	0.023*
C4	0.77323 (18)	0.9340 (2)	0.96005 (16)	0.0206 (3)
H4	0.7688	1.0519	0.9771	0.025*
C5	0.66301 (17)	0.8268 (2)	0.98885 (15)	0.0187 (3)
H5	0.5828	0.8721	1.0280	0.022*
C6	0.75688 (16)	0.39930 (19)	0.89076 (14)	0.0158 (3)
C7	1.03467 (16)	0.6349 (2)	0.82239 (15)	0.0179 (3)
O1	0.63949 (11)	0.33806 (14)	0.91765 (11)	0.0181 (2)
O2	0.85601 (12)	0.31061 (14)	0.85009 (11)	0.0203 (2)
O3	1.13066 (12)	0.74039 (15)	0.81237 (12)	0.0218 (3)
O4	1.05136 (14)	0.48120 (15)	0.78668 (14)	0.0261 (3)
H4A	0.9861	0.4162	0.8134	0.031*
O5	0.60695 (12)	0.44082 (15)	1.19303 (11)	0.0201 (2)
H5A	0.6325	0.5429	1.2381	0.024*
H5B	0.6920	0.3741	1.1955	0.024*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Zn1	0.01293 (15)	0.01436 (16)	0.02298 (16)	−0.00098 (8)	0.00569 (10)	−0.00054 (9)
N1	0.0137 (6)	0.0160 (6)	0.0182 (6)	0.0004 (5)	0.0023 (5)	0.0006 (5)
C1	0.0146 (7)	0.0143 (8)	0.0150 (7)	0.0005 (5)	0.0007 (5)	0.0006 (5)
C2	0.0137 (7)	0.0184 (8)	0.0148 (7)	0.0000 (6)	0.0017 (5)	0.0008 (6)
C3	0.0172 (7)	0.0186 (8)	0.0208 (7)	−0.0038 (6)	0.0022 (6)	0.0011 (6)
C4	0.0224 (8)	0.0144 (8)	0.0251 (8)	−0.0011 (6)	0.0027 (6)	−0.0009 (6)
C5	0.0173 (7)	0.0169 (8)	0.0224 (7)	0.0019 (6)	0.0045 (6)	−0.0002 (6)
C6	0.0163 (7)	0.0151 (8)	0.0159 (7)	−0.0005 (6)	0.0017 (6)	0.0010 (5)
C7	0.0149 (7)	0.0211 (8)	0.0179 (7)	0.0003 (6)	0.0021 (6)	0.0031 (6)
O1	0.0151 (5)	0.0158 (5)	0.0243 (5)	−0.0010 (4)	0.0054 (4)	−0.0009 (4)
O2	0.0171 (5)	0.0159 (5)	0.0290 (6)	0.0014 (4)	0.0073 (4)	−0.0010 (5)
O3	0.0149 (5)	0.0225 (6)	0.0286 (6)	−0.0013 (4)	0.0047 (4)	0.0033 (5)
O4	0.0192 (6)	0.0209 (6)	0.0405 (8)	−0.0022 (4)	0.0140 (5)	−0.0025 (5)
O5	0.0167 (5)	0.0196 (6)	0.0243 (6)	0.0018 (4)	0.0030 (4)	−0.0011 (5)

Geometric parameters (Å, º)

Zn1—O1	2.0602 (12)	C3—C4	1.377 (2)
Zn1—O1^i	2.0602 (12)	C3—H3	0.9500
Zn1—N1^i	2.0691 (14)	C4—C5	1.384 (2)
Zn1—N1	2.0691 (14)	C4—H4	0.9500
Zn1—O5	2.1858 (13)	C5—H5	0.9500
Zn1—O5^i	2.1858 (13)	C6—O1	1.2489 (19)
N1—C5	1.334 (2)	C6—O2	1.2604 (19)
N1—C1	1.3478 (19)	C7—O3	1.2333 (19)
C1—C2	1.406 (2)	C7—O4	1.283 (2)
C1—C6	1.543 (2)	O4—H4A	0.8600
C2—C3	1.401 (2)	O5—H5A	0.9500
C2—C7	1.527 (2)	O5—H5B	0.9500
O1—Zn1—O1^i	180.0	C3—C2—C7	114.50 (13)
O1—Zn1—N1^i	101.61 (6)	C1—C2—C7	128.45 (14)
O1^i—Zn1—N1^i	78.39 (5)	C4—C3—C2	121.50 (15)
O1—Zn1—N1	78.39 (6)	C4—C3—H3	119.2
O1^i—Zn1—N1	101.61 (6)	C2—C3—H3	119.2
N1^i—Zn1—N1	180.0	C3—C4—C5	117.84 (15)
O1—Zn1—O5	89.34 (5)	C3—C4—H4	121.1
O1^i—Zn1—O5	90.66 (5)	C5—C4—H4	121.1
N1^i—Zn1—O5	89.25 (5)	N1—C5—C4	121.79 (14)
N1—Zn1—O5	90.75 (5)	N1—C5—H5	119.1
O1—Zn1—O5^i	90.66 (5)	C4—C5—H5	119.1
O1^i—Zn1—O5^i	89.34 (5)	O1—C6—O2	122.63 (14)
N1^i—Zn1—O5^i	90.75 (5)	O1—C6—C1	117.58 (13)
N1—Zn1—O5^i	89.25 (5)	O2—C6—C1	119.78 (13)
O5—Zn1—O5^i	180.0	O3—C7—O4	120.60 (15)
C5—N1—C1	121.20 (13)	O3—C7—C2	118.49 (14)
C5—N1—Zn1	122.53 (10)	O4—C7—C2	120.90 (14)
C1—N1—Zn1	116.26 (10)	C6—O1—Zn1	116.54 (10)
N1—C1—C2	120.60 (14)	C7—O4—H4A	111.6
N1—C1—C6	111.00 (12)	Zn1—O5—H5A	109.4
C2—C1—C6	128.40 (13)	Zn1—O5—H5B	116.8
C3—C2—C1	117.05 (14)	H5A—O5—H5B	106.8

Symmetry code: (i) −x+1, −y+1, −z+2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O5—H5A···O3^ii	0.95	1.88	2.8035 (19)	164
O5—H5B···O3^iii	0.95	1.89	2.8358 (18)	174
O5—H5B···O4^iii	0.95	2.64	3.226 (2)	121
O4—H4A···O2	0.86	1.55	2.4017 (17)	173

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