In the title complex, [Zn(C8H3NO6)(H2O)3]n, the two carboxylate groups of the 4-nitrophthalate dianion ligands have monodentate and 1,3-bridging modes, and Zn atoms are interconnected by three O atoms from the two carboxylate groups into a zigzag one-dimensional chain along the b-axis direction. The Zn atom shows distorted octahedral coordination as it is bonded to three O atoms from carboxylate groups of three 4-nitrophthalate ligands and to three O atoms of three non-equivalent coordinated water molecules. The one-dimensional chains are aggregated into two-dimensional layers through inter-chain hydrogen bonding. The whole three-dimensional structure is further maintained and stabilized by inter-layer hydrogen bonds.
Supporting information
CCDC reference: 672423
Zinc oxide (0.25 g, 3 mmol) was added to a stirred solution of 4-nitrophthalic
acid (0.53 g, 2.5 mmol) in boiling water (20.0 ml) over a period of 20 min.
After filtration, slow evaporation over a period of two weeks at room
temperature provided colorless block crystals of (I).
All water H atoms were found in difference Fourier maps. However, during
refinement, they were fixed at O—H distances of 0.85–0.86 Å, with
Uiso(H) = 1.2Ueq(O). The H atoms of CH groups were treated
as riding [C—H = 0.93 Å and Uiso(H) = 1.2Ueq(C)].
Data collection: SMART (Bruker, 1997); cell refinement: SAINT (Bruker, 1997); data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXTL (Bruker, 2001); program(s) used to refine structure: SHELXTL (Bruker, 2001); molecular graphics: SHELXTL (Bruker, 2001); software used to prepare material for publication: SHELXTL (Bruker, 2001).
Poly[[triaquazinc(II)]-µ
3-4-nitrophthalato-
κ3O1:
O2:
O2']
top
Crystal data top
[Zn(C8H3NO6)(H2O)3] | Z = 2 |
Mr = 328.53 | F(000) = 332 |
Triclinic, P1 | Dx = 1.999 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 7.0758 (12) Å | Cell parameters from 2118 reflections |
b = 7.2954 (12) Å | θ = 2.9–26.4° |
c = 10.8601 (18) Å | µ = 2.30 mm−1 |
α = 97.317 (2)° | T = 294 K |
β = 91.591 (3)° | Block, colorless |
γ = 100.621 (3)° | 0.16 × 0.12 × 0.10 mm |
V = 545.76 (16) Å3 | |
Data collection top
Bruker SMART CCD area-detector diffractometer | 1910 independent reflections |
Radiation source: fine-focus sealed tube | 1751 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.014 |
ϕ and ω scans | θmax = 25.0°, θmin = 1.9° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −4→8 |
Tmin = 0.721, Tmax = 0.802 | k = −8→7 |
2827 measured reflections | l = −11→12 |
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) = 0.061 | H-atom parameters constrained |
S = 1.10 | w = 1/[σ2(Fo2) + (0.0284P)2 + 0.3243P] where P = (Fo2 + 2Fc2)/3 |
1910 reflections | (Δ/σ)max = 0.001 |
172 parameters | Δρmax = 0.36 e Å−3 |
0 restraints | Δρmin = −0.30 e Å−3 |
Crystal data top
[Zn(C8H3NO6)(H2O)3] | γ = 100.621 (3)° |
Mr = 328.53 | V = 545.76 (16) Å3 |
Triclinic, P1 | Z = 2 |
a = 7.0758 (12) Å | Mo Kα radiation |
b = 7.2954 (12) Å | µ = 2.30 mm−1 |
c = 10.8601 (18) Å | T = 294 K |
α = 97.317 (2)° | 0.16 × 0.12 × 0.10 mm |
β = 91.591 (3)° | |
Data collection top
Bruker SMART CCD area-detector diffractometer | 1910 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 1751 reflections with I > 2σ(I) |
Tmin = 0.721, Tmax = 0.802 | Rint = 0.014 |
2827 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.023 | 0 restraints |
wR(F2) = 0.061 | H-atom parameters constrained |
S = 1.10 | Δρmax = 0.36 e Å−3 |
1910 reflections | Δρmin = −0.30 e Å−3 |
172 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 | Uiso*/Ueq | |
Zn1 | 0.73363 (4) | 0.72401 (3) | 0.51171 (2) | 0.01684 (10) | |
N1 | 0.8284 (3) | 1.3633 (3) | −0.08471 (19) | 0.0292 (5) | |
O1 | 0.7470 (2) | 0.9260 (2) | 0.39132 (14) | 0.0197 (4) | |
O2 | 0.4497 (2) | 0.8256 (2) | 0.30185 (16) | 0.0271 (4) | |
O3 | 0.5308 (2) | 1.2522 (2) | 0.42111 (14) | 0.0204 (4) | |
O4 | 0.6836 (3) | 1.5216 (2) | 0.36131 (15) | 0.0235 (4) | |
O5 | 0.7759 (4) | 1.5152 (3) | −0.08435 (18) | 0.0470 (6) | |
O6 | 0.9301 (3) | 1.3021 (3) | −0.16324 (16) | 0.0383 (5) | |
O7 | 1.0296 (2) | 0.7342 (2) | 0.49359 (18) | 0.0318 (4) | |
H7A | 1.1122 | 0.8268 | 0.5284 | 0.038* | |
H7B | 1.0719 | 0.6506 | 0.4468 | 0.038* | |
O8 | 0.8372 (3) | 0.9363 (2) | 0.66810 (16) | 0.0283 (4) | |
H8A | 0.7490 | 1.0004 | 0.6847 | 0.034* | |
H8B | 0.9502 | 1.0039 | 0.6676 | 0.034* | |
O9 | 0.7582 (2) | 0.5117 (2) | 0.63649 (15) | 0.0241 (4) | |
H9A | 0.6722 | 0.4140 | 0.6416 | 0.029* | |
H9B | 0.8134 | 0.5671 | 0.7050 | 0.029* | |
C1 | 0.6131 (3) | 0.9245 (3) | 0.3099 (2) | 0.0172 (5) | |
C2 | 0.6666 (3) | 1.0470 (3) | 0.2087 (2) | 0.0166 (5) | |
C3 | 0.6713 (3) | 1.2418 (3) | 0.2248 (2) | 0.0167 (5) | |
C4 | 0.6241 (3) | 1.3472 (3) | 0.3461 (2) | 0.0167 (5) | |
C5 | 0.7201 (4) | 1.3433 (3) | 0.1261 (2) | 0.0216 (5) | |
H5 | 0.7197 | 1.4717 | 0.1345 | 0.026* | |
C6 | 0.7685 (3) | 1.2523 (3) | 0.0164 (2) | 0.0229 (5) | |
C7 | 0.7698 (4) | 1.0605 (3) | −0.0016 (2) | 0.0248 (5) | |
H7 | 0.8057 | 1.0023 | −0.0762 | 0.030* | |
C8 | 0.7155 (4) | 0.9586 (3) | 0.0955 (2) | 0.0232 (5) | |
H8 | 0.7117 | 0.8294 | 0.0850 | 0.028* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Zn1 | 0.01931 (16) | 0.01425 (15) | 0.01705 (15) | 0.00319 (11) | 0.00132 (10) | 0.00231 (10) |
N1 | 0.0372 (13) | 0.0280 (12) | 0.0187 (11) | −0.0038 (10) | −0.0023 (10) | 0.0046 (9) |
O1 | 0.0234 (9) | 0.0154 (8) | 0.0202 (8) | 0.0021 (7) | −0.0033 (7) | 0.0053 (6) |
O2 | 0.0244 (9) | 0.0227 (9) | 0.0330 (10) | −0.0022 (8) | −0.0033 (8) | 0.0099 (7) |
O3 | 0.0242 (9) | 0.0183 (8) | 0.0217 (8) | 0.0072 (7) | 0.0085 (7) | 0.0075 (7) |
O4 | 0.0361 (10) | 0.0131 (8) | 0.0199 (8) | 0.0023 (7) | 0.0043 (7) | −0.0004 (6) |
O5 | 0.0817 (17) | 0.0315 (11) | 0.0307 (11) | 0.0114 (11) | 0.0080 (11) | 0.0131 (9) |
O6 | 0.0373 (11) | 0.0519 (13) | 0.0224 (10) | −0.0009 (10) | 0.0090 (9) | 0.0050 (9) |
O7 | 0.0193 (9) | 0.0231 (9) | 0.0503 (12) | 0.0023 (7) | 0.0018 (8) | −0.0028 (8) |
O8 | 0.0276 (9) | 0.0249 (9) | 0.0298 (9) | 0.0024 (8) | −0.0022 (8) | −0.0025 (7) |
O9 | 0.0272 (9) | 0.0196 (9) | 0.0242 (9) | −0.0009 (7) | −0.0038 (7) | 0.0070 (7) |
C1 | 0.0215 (12) | 0.0116 (11) | 0.0189 (11) | 0.0055 (9) | 0.0010 (9) | 0.0000 (9) |
C2 | 0.0153 (11) | 0.0160 (11) | 0.0180 (11) | 0.0016 (9) | −0.0027 (9) | 0.0025 (9) |
C3 | 0.0197 (11) | 0.0146 (11) | 0.0154 (11) | 0.0030 (9) | −0.0009 (9) | 0.0018 (9) |
C4 | 0.0165 (11) | 0.0178 (12) | 0.0165 (11) | 0.0057 (9) | −0.0012 (9) | 0.0019 (9) |
C5 | 0.0272 (13) | 0.0148 (11) | 0.0216 (12) | 0.0010 (10) | −0.0011 (10) | 0.0029 (9) |
C6 | 0.0265 (13) | 0.0246 (13) | 0.0160 (11) | −0.0006 (10) | −0.0003 (10) | 0.0050 (10) |
C7 | 0.0291 (13) | 0.0268 (13) | 0.0172 (12) | 0.0046 (11) | 0.0031 (10) | −0.0014 (10) |
C8 | 0.0310 (13) | 0.0161 (12) | 0.0225 (12) | 0.0062 (10) | 0.0015 (10) | 0.0001 (10) |
Geometric parameters (Å, º) top
Zn1—O3i | 2.0561 (16) | O8—H8A | 0.8563 |
Zn1—O4ii | 2.0335 (16) | O8—H8B | 0.8594 |
Zn1—O1 | 2.0822 (15) | O9—H9A | 0.8561 |
Zn1—O7 | 2.0976 (18) | O9—H9B | 0.8480 |
Zn1—O8 | 2.1595 (16) | C1—C2 | 1.516 (3) |
Zn1—O9 | 2.2104 (16) | C2—C8 | 1.397 (3) |
N1—O6 | 1.225 (3) | C2—C3 | 1.404 (3) |
N1—O5 | 1.232 (3) | C3—C5 | 1.394 (3) |
N1—C6 | 1.472 (3) | C3—C4 | 1.516 (3) |
O1—C1 | 1.276 (3) | C5—C6 | 1.372 (3) |
O2—C1 | 1.240 (3) | C5—H5 | 0.9300 |
O3—C4 | 1.259 (3) | C6—C7 | 1.390 (3) |
O4—C4 | 1.252 (3) | C7—C8 | 1.389 (4) |
O7—H7A | 0.8474 | C7—H7 | 0.9300 |
O7—H7B | 0.8466 | C8—H8 | 0.9300 |
| | | |
O4ii—Zn1—O3i | 106.52 (7) | Zn1—O9—H9A | 124.8 |
O4ii—Zn1—O1 | 88.65 (6) | Zn1—O9—H9B | 108.9 |
O3i—Zn1—O1 | 97.36 (6) | H9A—O9—H9B | 115.4 |
O4ii—Zn1—O7 | 88.42 (7) | O2—C1—O1 | 126.5 (2) |
O3i—Zn1—O7 | 164.03 (7) | O2—C1—C2 | 117.6 (2) |
O1—Zn1—O7 | 88.41 (7) | O1—C1—C2 | 115.74 (19) |
O4ii—Zn1—O8 | 170.33 (7) | C8—C2—C3 | 119.7 (2) |
O3i—Zn1—O8 | 83.02 (7) | C8—C2—C1 | 117.2 (2) |
O1—Zn1—O8 | 91.70 (7) | C3—C2—C1 | 123.2 (2) |
O7—Zn1—O8 | 81.93 (7) | C5—C3—C2 | 119.3 (2) |
O4ii—Zn1—O9 | 91.12 (6) | C5—C3—C4 | 118.3 (2) |
O3i—Zn1—O9 | 89.54 (6) | C2—C3—C4 | 122.3 (2) |
O1—Zn1—O9 | 172.87 (6) | O4—C4—O3 | 126.6 (2) |
O7—Zn1—O9 | 84.46 (7) | O4—C4—C3 | 115.9 (2) |
O8—Zn1—O9 | 87.34 (7) | O3—C4—C3 | 117.5 (2) |
O6—N1—O5 | 123.4 (2) | C6—C5—C3 | 119.5 (2) |
O6—N1—C6 | 118.7 (2) | C6—C5—H5 | 120.2 |
O5—N1—C6 | 117.9 (2) | C3—C5—H5 | 120.2 |
C1—O1—Zn1 | 122.83 (14) | C5—C6—C7 | 122.6 (2) |
C4—O3—Zn1i | 127.99 (14) | C5—C6—N1 | 118.7 (2) |
C4—O4—Zn1iii | 134.46 (15) | C7—C6—N1 | 118.6 (2) |
Zn1—O7—H7A | 121.4 | C8—C7—C6 | 117.8 (2) |
Zn1—O7—H7B | 121.7 | C8—C7—H7 | 121.1 |
H7A—O7—H7B | 116.7 | C6—C7—H7 | 121.1 |
Zn1—O8—H8A | 108.2 | C7—C8—C2 | 121.0 (2) |
Zn1—O8—H8B | 119.1 | C7—C8—H8 | 119.5 |
H8A—O8—H8B | 113.8 | C2—C8—H8 | 119.5 |
Symmetry codes: (i) −x+1, −y+2, −z+1; (ii) x, y−1, z; (iii) x, y+1, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O9—H9B···O5iv | 0.85 | 2.38 | 3.027 (3) | 134 |
O8—H8A···O2i | 0.86 | 2.06 | 2.904 (3) | 170 |
O9—H9A···O2v | 0.86 | 1.98 | 2.794 (2) | 158 |
O7—H7A···O1vi | 0.85 | 1.97 | 2.804 (2) | 166 |
O7—H7B···O9vii | 0.85 | 1.99 | 2.817 (2) | 164 |
O8—H8B···O1vi | 0.86 | 2.24 | 3.043 (2) | 156 |
Symmetry codes: (i) −x+1, −y+2, −z+1; (iv) x, y−1, z+1; (v) −x+1, −y+1, −z+1; (vi) −x+2, −y+2, −z+1; (vii) −x+2, −y+1, −z+1. |
Experimental details
Crystal data |
Chemical formula | [Zn(C8H3NO6)(H2O)3] |
Mr | 328.53 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 294 |
a, b, c (Å) | 7.0758 (12), 7.2954 (12), 10.8601 (18) |
α, β, γ (°) | 97.317 (2), 91.591 (3), 100.621 (3) |
V (Å3) | 545.76 (16) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 2.30 |
Crystal size (mm) | 0.16 × 0.12 × 0.10 |
|
Data collection |
Diffractometer | Bruker SMART CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.721, 0.802 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2827, 1910, 1751 |
Rint | 0.014 |
(sin θ/λ)max (Å−1) | 0.595 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.023, 0.061, 1.10 |
No. of reflections | 1910 |
No. of parameters | 172 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.36, −0.30 |
Selected geometric parameters (Å, º) topZn1—O3i | 2.0561 (16) | Zn1—O9 | 2.2104 (16) |
Zn1—O4ii | 2.0335 (16) | O1—C1 | 1.276 (3) |
Zn1—O1 | 2.0822 (15) | O2—C1 | 1.240 (3) |
Zn1—O7 | 2.0976 (18) | O3—C4 | 1.259 (3) |
Zn1—O8 | 2.1595 (16) | O4—C4 | 1.252 (3) |
| | | |
O4ii—Zn1—O3i | 106.52 (7) | O7—Zn1—O8 | 81.93 (7) |
O4ii—Zn1—O1 | 88.65 (6) | O4ii—Zn1—O9 | 91.12 (6) |
O3i—Zn1—O1 | 97.36 (6) | O3i—Zn1—O9 | 89.54 (6) |
O4ii—Zn1—O7 | 88.42 (7) | O1—Zn1—O9 | 172.87 (6) |
O3i—Zn1—O7 | 164.03 (7) | O7—Zn1—O9 | 84.46 (7) |
O1—Zn1—O7 | 88.41 (7) | O8—Zn1—O9 | 87.34 (7) |
O4ii—Zn1—O8 | 170.33 (7) | O2—C1—O1 | 126.5 (2) |
O3i—Zn1—O8 | 83.02 (7) | O4—C4—O3 | 126.6 (2) |
O1—Zn1—O8 | 91.70 (7) | | |
Symmetry codes: (i) −x+1, −y+2, −z+1; (ii) x, y−1, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O9—H9B···O5iii | 0.85 | 2.38 | 3.027 (3) | 134 |
O8—H8A···O2i | 0.86 | 2.06 | 2.904 (3) | 170 |
O9—H9A···O2iv | 0.86 | 1.98 | 2.794 (2) | 158 |
O7—H7A···O1v | 0.85 | 1.97 | 2.804 (2) | 166 |
O7—H7B···O9vi | 0.85 | 1.99 | 2.817 (2) | 164 |
O8—H8B···O1v | 0.86 | 2.24 | 3.043 (2) | 156 |
Symmetry codes: (i) −x+1, −y+2, −z+1; (iii) x, y−1, z+1; (iv) −x+1, −y+1, −z+1; (v) −x+2, −y+2, −z+1; (vi) −x+2, −y+1, −z+1. |
Aromatic dicarboxylate ligands such as phthalate (phth) have been used in architecture of polymeric metal complexes because they can act in bis-monodentate, bis-bidentate and combined coordination modes to form short bridges via one carboxylate end or long bridges via the benzene ring and lead to a great variety of structures. For example, as a bis-monodentate ligand, the phthalate dianion is known to bond to metals, leading to a one-dimensional chain complex, e.g. in {[Cu(phth)(1,10-phenanthroline)(H2O)]·H2O}n (Ye, Sun et al., 2005), [Mn(phth)(pyrazine)(H2O)2]n (Ma et al., 2004) and [Zn(phth)(1-methylimidazole)2]n (Baca et al., 2004). On the other hand, in bis-bidentate and combined modes of coordination, the phthalate dianion can be found chelating through the two carboxylate O atoms, as in [Co(phth)(2,2'-biimidazole)2] (Ye, Ding et al. 2005), {[Ni(phth)(4,4'-bipyridine)(H2O)]·3H2O}n (Yang et al., 2003), [(bpy)2Zn(Phth)H(Phth)Zn(bpy)2](Hphth)(H2Phth)·2H2O (bpy is 2,2-bipyridine) (Baca et al., 2003) and {[Cu2(phth)2(imidazole)4(H2O)]·H2O}n (Fu et al., 2006). However, in spite of this wealth of possibilities, only a few complexes of metal–nitrophthalate systems have been reported to date. We have used the 4-nitrophthalate dianion as a ligand, and obtained the title novel six-coordinate 4-nitrophthalate–zinc complex, (I). We describe here the structure of this one-dimensional metal–nitrophthalate coordination polymer, in which O—H···O inter-chain bonding leads to a three-dimensional supramolecular network.
The asymmetric unit in (I) comprises one Zn atom, one complete 4-nitrophthate dianion and three nonequivalent water molecules and is shown in Fig. 1 in a symmetry-expanded view, which displays the full coordination of the Zn atom. Selected geometric parameters are given in Table 1.
The Zn atom is octahedrally coordinated by six O-atom donors (Fig. 1). The four equatorial coordination sites are occupied by two coordinated water molecules (O7 and O8) and two O atoms (O4ii and O3i) from two 4-nitrophthalate ligands. Atom O1 and the third coordinated water molecule (O9) occupy the apical sites of the octahedron. The Zn—O(water) distances range from 2.0976 (18) to 2.2104 (16) Å and the Zn—O(4-nitrophthalate) distances cover the range 2.0335 (16)–2.0822 (15) Å. The Zn—O(water) bonds are slightly longer than those in [Zn(2-nitroterephthalate)(H2O)3]·H2O (Guo & Guo, 2007), where they range from 2.051 (2) to 2.090 (2) Å. The cis O—Zn—O bond angles in (I) range from 81.93 (7) to 106.52 (7)°, and the trans O—Zn—O bond angles cover the range 164.03 (7)–172.87 (6)°. Thus, the structure of the title complex shows the Zn atom centre to be in a distorted octahedral environment with a facial disposition of water molecules.
In the present structure, monodentate, bidentate 1,3-bridging and 1,6-bridging modes via the benzene ring are present (Fig. 2). Atom O1 has a monodentate mode, and atoms O3 and O4 have both a monodentate mode and a bidentate 1,3-bridging mode of connection with two Zn atoms. The Zn atoms are interconnected by three O atoms from the two carboxylate groups of the 4-nitrophthalate dianion into a zigzag one-dimensional chain along the b-axis direction. In the chain, atoms O1 and O3 adopt a 1,6-bridging bonding mode via the benzene ring to connect with two Zn atoms. In this way, two 4-nitrophthalate dianions interconnect with Zn atoms into two different rings, viz. 14-membered and eight-membered, with the 4-nitrophthalate anions arranged alternately along the infinite one-dimensional chains (Fig. 2). This results in Zn···Zn separations within the chains of 5.686 (1) and 4.176 (6) Å. The mean planes of the O1/C1/O2 carboxylate group and the benzene ring make a dihedral angle of 80.0 (3)°, and the corresponding value for the O3/C4/O4 carboxylate group is 19.1 (3)°; the C—O bond lengths (O1—C1 and O2—C1) of the monodentate carboxylate group are 1.276 (3) and 1.240 (3) Å, respectively, and the C—O bond lengths (O3—C4 and O4—C4) of the 1,3-bridging carboxylate group are 1.259 (3) and 1.252 (3) Å, respectively. This indicates that the mesomeric effect for the 1,3-bridging carboxylate group is somewhat greater than that of the monodentate carboxylate group.
The three water molecules and the nitro group (O5/N1/O6) are engaged in distinct hydrogen-bond interactions (Table 2). In the bc plane, neighbouring chains are linked via O9—H9B···O5iii weak hydrogen-bond interactions. In this way, a complete two-dimensional layer is formed parallel to the bc plane. The noncoordinated O2 atom is involved in two hydrogen bonds, O8—H8A···O2i and O9–H9A···O2iv; these play an important role in the propagation of the one-dimensional chain structure, because they participate in the formation of two 12-membered hydrogen-bonded rings [R22(12) graph sets; Bernstein et al., 1995] (Fig. 2). This also results in the aryl rings of the 4-nitrophthalate ligands stacking in an offset fashion along the a-axis direction. In the crystallographic ab plane, O7—H7A···O1v, O7—H7B···O9vi and O8—H8B···O1v hydrogen bonds link neighbouring chains together via three different R22(8) rings and complete a two-dimensional layer parallel to the ab plane (Fig. 3). Thus, the three-dimensional connectivity of the structure is achieved.