The title complex, {[Zn(C8H3NO6)(H2O)3]·H2O}n, has a one-dimensional chain structure. The two carboxylate groups of the dianionic 2-nitroterephthalate ligand adopt mono- and bidentate chelating modes. The Zn atom shows distorted octahedral coordination, bonded to three O atoms from two carboxylate groups and 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 stabilized by inter-layer hydrogen bonds.
Supporting information
CCDC reference: 659108
The addition of anhydrous sodium carbonate (0.43 g, 4 mmol) to a stirred
solution of zinc nitrate hexahydrate (1.2 g, 4 mmol) in water (30 ml) produced
a white precipitate, which was filtered off and washed with distilled water.
The precipitate was subsequently added to a stirred solution of
2-nitroterephthalic acid (0.53 g, 2.5 mmol) in boiling water (20.0 ml) over a
period of 5 min. After filtration, slow evaporation over a period of two weeks
at room temperature provided colourless needle-like crystals of (I).
All water H atoms were found in difference Fourier maps and were fixed during
refinement at O—H distances of 0.85 Å, with Uiso(H) =
1.2Ueq(O). The noncoordinated water molecule is disordered over at
least two sites; the refined occupancy factors for atoms O10 and O10' were
0.740 (2):0.260 (2). The H atoms of the CH groups were treated as riding, with
C—-H = 0.93 Å and Uiso (H) = 1.2Ueq(C).
Data collection: SMART (Bruker, 1997); cell refinement: SMART; data reduction: SAINT (Bruker, 1997); program(s) used to solve structure: SHELXTL (Bruker, 2001); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
catena-Poly[[[triaquazinc(II)]-µ-2-nitroterephthalato-
κO1:
κ2O4:
O4'] monohydrate]
top
Crystal data top
[Zn(C8H3NO6)(H2O)3]·H2O | F(000) = 704 |
Mr = 346.55 | Dx = 1.892 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 3987 reflections |
a = 7.8862 (12) Å | θ = 2.7–26.4° |
b = 20.501 (5) Å | µ = 2.07 mm−1 |
c = 7.7119 (13) Å | T = 294 K |
β = 102.633 (16)° | Needle, colourless |
V = 1216.6 (4) Å3 | 0.20 × 0.12 × 0.08 mm |
Z = 4 | |
Data collection top
Bruker SMART CCD area-detector diffractometer | 2489 independent reflections |
Radiation source: fine-focus sealed tube | 2153 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.031 |
ϕ and ω scans | θmax = 26.4°, θmin = 2.0° |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −9→9 |
Tmin = 0.743, Tmax = 0.845 | k = −25→25 |
6933 measured reflections | l = −9→7 |
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)] = 0.034 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.081 | H-atom parameters constrained |
S = 1.12 | w = 1/[σ2(Fo2) + (0.0293P)2 + 1.2254P] where P = (Fo2 + 2Fc2)/3 |
2489 reflections | (Δ/σ)max = 0.001 |
191 parameters | Δρmax = 0.47 e Å−3 |
36 restraints | Δρmin = −0.59 e Å−3 |
Crystal data top
[Zn(C8H3NO6)(H2O)3]·H2O | V = 1216.6 (4) Å3 |
Mr = 346.55 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 7.8862 (12) Å | µ = 2.07 mm−1 |
b = 20.501 (5) Å | T = 294 K |
c = 7.7119 (13) Å | 0.20 × 0.12 × 0.08 mm |
β = 102.633 (16)° | |
Data collection top
Bruker SMART CCD area-detector diffractometer | 2489 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 2153 reflections with I > 2σ(I) |
Tmin = 0.743, Tmax = 0.845 | Rint = 0.031 |
6933 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.034 | 36 restraints |
wR(F2) = 0.081 | H-atom parameters constrained |
S = 1.12 | Δρmax = 0.47 e Å−3 |
2489 reflections | Δρmin = −0.59 e Å−3 |
191 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 | Occ. (<1) |
Zn1 | 0.22101 (4) | 0.467979 (15) | 0.28529 (4) | 0.02152 (12) | |
O1 | 0.0652 (3) | 0.39115 (10) | 0.2286 (3) | 0.0309 (5) | |
O2 | −0.1723 (3) | 0.40738 (11) | 0.3381 (4) | 0.0447 (6) | |
O3 | −0.0487 (3) | 0.05413 (10) | 0.2672 (3) | 0.0269 (5) | |
O4 | −0.3295 (3) | 0.07002 (9) | 0.1823 (3) | 0.0253 (4) | |
O5 | 0.2112 (3) | 0.32597 (11) | 0.5516 (3) | 0.0390 (6) | |
O6 | 0.3313 (4) | 0.24550 (15) | 0.4486 (5) | 0.0745 (10) | |
O7 | 0.2489 (3) | 0.47581 (10) | 0.0228 (3) | 0.0341 (5) | |
H7A | 0.1476 | 0.4708 | −0.0428 | 0.041* | |
H7B | 0.3275 | 0.4513 | −0.0016 | 0.041* | |
O8 | 0.2161 (3) | 0.47102 (9) | 0.5550 (3) | 0.0275 (5) | |
H8A | 0.2056 | 0.5100 | 0.5900 | 0.033* | |
H8B | 0.1522 | 0.4428 | 0.5903 | 0.033* | |
O9 | 0.4523 (3) | 0.41850 (11) | 0.3481 (3) | 0.0345 (5) | |
H9A | 0.5102 | 0.4196 | 0.4553 | 0.041* | |
H9B | 0.5115 | 0.4139 | 0.2692 | 0.041* | |
N1 | 0.2041 (4) | 0.27768 (13) | 0.4582 (4) | 0.0337 (6) | |
C1 | −0.0659 (4) | 0.37277 (13) | 0.2858 (4) | 0.0241 (6) | |
C2 | −0.0942 (4) | 0.29950 (13) | 0.2839 (4) | 0.0215 (6) | |
C3 | 0.0347 (4) | 0.25498 (13) | 0.3568 (4) | 0.0226 (6) | |
C4 | 0.0096 (4) | 0.18809 (13) | 0.3430 (4) | 0.0233 (6) | |
H4 | 0.0987 | 0.1597 | 0.3932 | 0.028* | |
C5 | −0.1496 (4) | 0.16416 (13) | 0.2534 (4) | 0.0197 (6) | |
C6 | −0.2820 (4) | 0.20755 (13) | 0.1810 (4) | 0.0254 (6) | |
H6 | −0.3897 | 0.1917 | 0.1220 | 0.030* | |
C7 | −0.2542 (4) | 0.27463 (14) | 0.1966 (4) | 0.0280 (7) | |
H7 | −0.3437 | 0.3031 | 0.1480 | 0.034* | |
C8 | −0.1777 (4) | 0.09209 (13) | 0.2331 (4) | 0.0216 (6) | |
O10 | 0.4654 (9) | 0.1118 (4) | 0.4247 (10) | 0.0486 (17) | 0.74 (2) |
H10A | 0.5747 | 0.1067 | 0.4381 | 0.058* | 0.74 (2) |
H10B | 0.4192 | 0.1426 | 0.3569 | 0.058* | 0.74 (2) |
O10' | 0.520 (3) | 0.0882 (11) | 0.484 (2) | 0.042 (4) | 0.26 (2) |
H11A | 0.4983 | 0.0969 | 0.3728 | 0.051* | 0.26 (2) |
H11B | 0.6271 | 0.0841 | 0.5343 | 0.051* | 0.26 (2) |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Zn1 | 0.0253 (2) | 0.01378 (17) | 0.02494 (19) | −0.00018 (14) | 0.00439 (13) | 0.00049 (13) |
O1 | 0.0386 (13) | 0.0196 (10) | 0.0370 (13) | −0.0119 (9) | 0.0137 (10) | −0.0055 (9) |
O2 | 0.0514 (16) | 0.0201 (11) | 0.0701 (18) | −0.0018 (11) | 0.0300 (14) | −0.0123 (11) |
O3 | 0.0283 (12) | 0.0169 (9) | 0.0338 (12) | 0.0037 (9) | 0.0030 (9) | −0.0011 (8) |
O4 | 0.0257 (11) | 0.0174 (9) | 0.0314 (11) | −0.0055 (9) | 0.0028 (9) | −0.0007 (8) |
O5 | 0.0504 (15) | 0.0296 (12) | 0.0315 (12) | −0.0116 (11) | −0.0030 (10) | −0.0086 (10) |
O6 | 0.0327 (15) | 0.0563 (17) | 0.123 (3) | 0.0034 (14) | −0.0091 (16) | −0.0356 (18) |
O7 | 0.0362 (13) | 0.0399 (13) | 0.0260 (11) | 0.0002 (11) | 0.0063 (9) | −0.0012 (9) |
O8 | 0.0393 (13) | 0.0169 (9) | 0.0275 (11) | −0.0028 (9) | 0.0101 (9) | −0.0021 (8) |
O9 | 0.0295 (12) | 0.0420 (13) | 0.0308 (12) | 0.0098 (10) | 0.0038 (9) | −0.0015 (10) |
N1 | 0.0288 (15) | 0.0234 (13) | 0.0449 (16) | −0.0034 (11) | −0.0009 (12) | −0.0042 (11) |
C1 | 0.0324 (17) | 0.0160 (14) | 0.0232 (15) | −0.0034 (12) | 0.0044 (12) | −0.0042 (11) |
C2 | 0.0290 (16) | 0.0144 (13) | 0.0234 (14) | −0.0018 (12) | 0.0104 (12) | −0.0036 (11) |
C3 | 0.0230 (15) | 0.0190 (13) | 0.0254 (14) | −0.0053 (11) | 0.0045 (11) | −0.0050 (11) |
C4 | 0.0266 (16) | 0.0168 (13) | 0.0258 (15) | 0.0012 (12) | 0.0040 (12) | −0.0015 (11) |
C5 | 0.0233 (15) | 0.0135 (12) | 0.0231 (14) | −0.0027 (11) | 0.0067 (11) | −0.0009 (10) |
C6 | 0.0227 (15) | 0.0162 (13) | 0.0347 (17) | −0.0023 (12) | 0.0007 (12) | −0.0030 (12) |
C7 | 0.0272 (17) | 0.0163 (14) | 0.0386 (18) | 0.0022 (12) | 0.0032 (13) | 0.0018 (12) |
C8 | 0.0271 (16) | 0.0160 (13) | 0.0218 (14) | 0.0004 (12) | 0.0053 (12) | −0.0010 (11) |
O10 | 0.046 (3) | 0.043 (3) | 0.062 (3) | 0.000 (2) | 0.023 (2) | −0.002 (2) |
O10' | 0.039 (6) | 0.051 (6) | 0.042 (6) | −0.009 (4) | 0.021 (4) | 0.000 (4) |
Geometric parameters (Å, º) top
Zn1—O3i | 2.211 (2) | N1—C3 | 1.469 (4) |
Zn1—O4i | 2.253 (2) | C1—C2 | 1.518 (4) |
Zn1—O1 | 1.987 (2) | C2—C3 | 1.390 (4) |
Zn1—O9 | 2.051 (2) | C2—C7 | 1.390 (4) |
Zn1—O8 | 2.089 (2) | C3—C4 | 1.386 (4) |
Zn1—O7 | 2.090 (2) | C4—C5 | 1.384 (4) |
O1—C1 | 1.267 (4) | C4—H4 | 0.9300 |
O2—C1 | 1.232 (4) | C5—C6 | 1.392 (4) |
O3—C8 | 1.262 (4) | C5—C8 | 1.497 (4) |
O4—C8 | 1.259 (4) | C6—C7 | 1.394 (4) |
O5—N1 | 1.218 (3) | C6—H6 | 0.9300 |
O6—N1 | 1.216 (4) | C7—H7 | 0.9300 |
O7—H7A | 0.8526 | O10—H10A | 0.8515 |
O7—H7B | 0.8504 | O10—H10B | 0.8486 |
O8—H8A | 0.8536 | O10—H11A | 0.6061 |
O8—H8B | 0.8503 | O10'—H10A | 0.7188 |
O9—H9A | 0.8530 | O10'—H11A | 0.8535 |
O9—H9B | 0.8492 | O10'—H11B | 0.8516 |
| | | |
O1—Zn1—O9 | 97.77 (9) | O2—C1—C2 | 117.6 (3) |
O1—Zn1—O8 | 95.59 (8) | O1—C1—C2 | 114.9 (3) |
O9—Zn1—O8 | 89.37 (9) | C3—C2—C7 | 117.4 (3) |
O1—Zn1—O7 | 92.22 (9) | C3—C2—C1 | 123.5 (3) |
O9—Zn1—O7 | 89.44 (9) | C7—C2—C1 | 118.9 (3) |
O1—Zn1—O3i | 105.49 (9) | C4—C3—C2 | 122.6 (3) |
O8—Zn1—O3i | 90.80 (8) | C4—C3—N1 | 116.9 (3) |
O7—Zn1—O3i | 87.24 (8) | C2—C3—N1 | 120.5 (2) |
O9—Zn1—O4i | 97.85 (8) | C5—C4—C3 | 119.2 (3) |
O8—Zn1—O4i | 87.20 (7) | C5—C4—H4 | 120.4 |
O7—Zn1—O4i | 85.32 (8) | C3—C4—H4 | 120.4 |
O3i—Zn1—O4i | 58.80 (8) | C4—C5—C6 | 119.5 (3) |
O8—Zn1—O7 | 172.19 (8) | C4—C5—C8 | 120.0 (3) |
O9—Zn1—O3i | 156.60 (9) | C6—C5—C8 | 120.5 (3) |
O1—Zn1—O4i | 164.16 (9) | C5—C6—C7 | 120.4 (3) |
C1—O1—Zn1 | 132.19 (19) | C5—C6—H6 | 119.8 |
C8—O3—Zn1ii | 91.10 (17) | C7—C6—H6 | 119.8 |
C8—O4—Zn1ii | 89.26 (17) | C2—C7—C6 | 120.9 (3) |
Zn1—O7—H7A | 106.4 | C2—C7—H7 | 119.6 |
Zn1—O7—H7B | 113.9 | C6—C7—H7 | 119.6 |
H7A—O7—H7B | 115.6 | O4—C8—O3 | 120.8 (3) |
Zn1—O8—H8A | 111.6 | O4—C8—C5 | 119.7 (3) |
Zn1—O8—H8B | 116.1 | O3—C8—C5 | 119.5 (3) |
H8A—O8—H8B | 115.6 | O4—C8—Zn1ii | 61.36 (14) |
Zn1—O9—H9A | 118.4 | C5—C8—Zn1ii | 177.2 (2) |
Zn1—O9—H9B | 119.1 | H10A—O10—H10B | 117.0 |
H9A—O9—H9B | 115.9 | H10A—O10—H11A | 56.6 |
O6—N1—O5 | 123.0 (3) | H10B—O10—H11A | 99.0 |
O6—N1—C3 | 117.5 (3) | H10A—O10'—H11A | 54.0 |
O5—N1—C3 | 119.4 (3) | H10A—O10'—H11B | 68.9 |
O2—C1—O1 | 127.5 (3) | H11A—O10'—H11B | 116.4 |
| | | |
O9—Zn1—O1—C1 | 126.0 (3) | O5—N1—C3—C2 | 35.9 (4) |
O8—Zn1—O1—C1 | 35.9 (3) | C2—C3—C4—C5 | −0.1 (4) |
O7—Zn1—O1—C1 | −144.3 (3) | N1—C3—C4—C5 | 178.0 (3) |
O3i—Zn1—O1—C1 | −56.5 (3) | C3—C4—C5—C6 | −0.8 (4) |
O4i—Zn1—O1—C1 | −63.6 (4) | C3—C4—C5—C8 | 178.5 (3) |
C8i—Zn1—O1—C1 | −59.3 (3) | C4—C5—C6—C7 | 0.7 (4) |
Zn1—O1—C1—O2 | 30.8 (5) | C8—C5—C6—C7 | −178.5 (3) |
Zn1—O1—C1—C2 | −150.8 (2) | C3—C2—C7—C6 | −1.0 (4) |
O2—C1—C2—C3 | −130.5 (3) | C1—C2—C7—C6 | 175.6 (3) |
O1—C1—C2—C3 | 51.0 (4) | C5—C6—C7—C2 | 0.2 (5) |
O2—C1—C2—C7 | 53.1 (4) | Zn1ii—O4—C8—O3 | 2.9 (3) |
O1—C1—C2—C7 | −125.4 (3) | Zn1ii—O4—C8—C5 | −177.1 (2) |
C7—C2—C3—C4 | 1.0 (4) | Zn1ii—O3—C8—O4 | −3.0 (3) |
C1—C2—C3—C4 | −175.4 (3) | Zn1ii—O3—C8—C5 | 177.0 (2) |
C7—C2—C3—N1 | −177.1 (3) | C4—C5—C8—O4 | 166.7 (3) |
C1—C2—C3—N1 | 6.5 (4) | C6—C5—C8—O4 | −14.1 (4) |
O6—N1—C3—C4 | 35.4 (4) | C4—C5—C8—O3 | −13.3 (4) |
O5—N1—C3—C4 | −142.3 (3) | C6—C5—C8—O3 | 165.9 (3) |
O6—N1—C3—C2 | −146.4 (3) | | |
Symmetry codes: (i) −x, y+1/2, −z+1/2; (ii) −x, y−1/2, −z+1/2. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O8—H8B···O3iii | 0.85 | 2.31 | 2.966 (3) | 135 |
O7—H7A···O3iv | 0.85 | 1.95 | 2.783 (3) | 164 |
O7—H7B···O10iv | 0.85 | 1.86 | 2.699 (5) | 169 |
O9—H9B···O10′iv | 0.85 | 2.22 | 2.977 (14) | 149 |
O7—H7B···O10′iv | 0.85 | 1.75 | 2.584 (11) | 167 |
O10—H10B···O6 | 0.85 | 2.38 | 2.957 (9) | 126 |
O8—H8B···O5 | 0.85 | 2.47 | 2.974 (3) | 119 |
O9—H9B···O2v | 0.85 | 2.44 | 2.987 (3) | 123 |
O10—H10A···O4v | 0.85 | 2.38 | 2.858 (5) | 116 |
O10′—H11A···O4v | 0.85 | 2.28 | 2.855 (11) | 125 |
O8—H8A···O2vi | 0.85 | 1.82 | 2.672 (3) | 177 |
O9—H9A···O4vii | 0.85 | 1.93 | 2.778 (3) | 170 |
O10′—H11B···O7viii | 0.85 | 2.50 | 2.94 (3) | 113 |
Symmetry codes: (iii) x, −y+1/2, z+1/2; (iv) x, −y+1/2, z−1/2; (v) x+1, y, z; (vi) −x, −y+1, −z+1; (vii) x+1, −y+1/2, z+1/2; (viii) −x+1, y−1/2, −z+1/2. |
Experimental details
Crystal data |
Chemical formula | [Zn(C8H3NO6)(H2O)3]·H2O |
Mr | 346.55 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 294 |
a, b, c (Å) | 7.8862 (12), 20.501 (5), 7.7119 (13) |
β (°) | 102.633 (16) |
V (Å3) | 1216.6 (4) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 2.07 |
Crystal size (mm) | 0.20 × 0.12 × 0.08 |
|
Data collection |
Diffractometer | Bruker SMART CCD area-detector diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.743, 0.845 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 6933, 2489, 2153 |
Rint | 0.031 |
(sin θ/λ)max (Å−1) | 0.625 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.034, 0.081, 1.12 |
No. of reflections | 2489 |
No. of parameters | 191 |
No. of restraints | 36 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.47, −0.59 |
Selected geometric parameters (Å, º) topZn1—O3i | 2.211 (2) | Zn1—O7 | 2.090 (2) |
Zn1—O4i | 2.253 (2) | O1—C1 | 1.267 (4) |
Zn1—O1 | 1.987 (2) | O2—C1 | 1.232 (4) |
Zn1—O9 | 2.051 (2) | O3—C8 | 1.262 (4) |
Zn1—O8 | 2.089 (2) | O4—C8 | 1.259 (4) |
| | | |
O1—Zn1—O9 | 97.77 (9) | O9—Zn1—O4i | 97.85 (8) |
O1—Zn1—O8 | 95.59 (8) | O8—Zn1—O4i | 87.20 (7) |
O9—Zn1—O8 | 89.37 (9) | O7—Zn1—O4i | 85.32 (8) |
O1—Zn1—O7 | 92.22 (9) | O3i—Zn1—O4i | 58.80 (8) |
O9—Zn1—O7 | 89.44 (9) | O8—Zn1—O7 | 172.19 (8) |
O1—Zn1—O3i | 105.49 (9) | O9—Zn1—O3i | 156.60 (9) |
O8—Zn1—O3i | 90.80 (8) | O1—Zn1—O4i | 164.16 (9) |
O7—Zn1—O3i | 87.24 (8) | O2—C1—O1 | 127.5 (3) |
Symmetry code: (i) −x, y+1/2, −z+1/2. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O8—H8B···O3ii | 0.85 | 2.31 | 2.966 (3) | 134.6 |
O7—H7A···O3iii | 0.85 | 1.95 | 2.783 (3) | 164.2 |
O7—H7B···O10iii | 0.85 | 1.86 | 2.699 (5) | 169.4 |
O9—H9B···O10'iii | 0.85 | 2.22 | 2.977 (14) | 148.7 |
O7—H7B···O10'iii | 0.85 | 1.75 | 2.584 (11) | 167.1 |
O10—H10B···O6 | 0.85 | 2.38 | 2.957 (9) | 126.2 |
O8—H8B···O5 | 0.85 | 2.47 | 2.974 (3) | 118.8 |
O9—H9B···O2iv | 0.85 | 2.44 | 2.987 (3) | 123.1 |
O10—H10A···O4iv | 0.85 | 2.38 | 2.858 (5) | 115.8 |
O10'—H11A···O4iv | 0.85 | 2.28 | 2.855 (11) | 125.3 |
O8—H8A···O2v | 0.85 | 1.82 | 2.672 (3) | 177.3 |
O9—H9A···O4vi | 0.85 | 1.93 | 2.778 (3) | 170.3 |
O10'—H11B···O7vii | 0.85 | 2.50 | 2.94 (3) | 113.1 |
Symmetry codes: (ii) x, −y+1/2, z+1/2; (iii) x, −y+1/2, z−1/2; (iv) x+1, y, z; (v) −x, −y+1, −z+1; (vi) x+1, −y+1/2, z+1/2; (vii) −x+1, y−1/2, −z+1/2. |
Metal–organic networks or coordination polymers have attracted much attention recently in the area of topology design and for their potential applications in adsorption, catalysis, luminescence, magnetism etc. (Blatov et al., 2004; James, 2003; Janiak, 2003). The use of dicarboxylate ligands as small building blocks to generate metal–organic frameworks of different dimensionalities may lead to interesting network architectures (Rodríguez-Martín et al., 2002; Guo & Zhao, 2006). In particular, aromatic dicarboxylate ligands such as terephthalate (benzene-1,4-dicarboxylate, bdc) have been used in the architecture of polymeric metal complexes because they can adopt bis-monodentate, bis-bidentate and combined modes of coordination to form short bridges via one carboxylate end, or long bridges via the aromatic ring, and this can lead to a great variety of structures. For example, as a bis-monodentate ligand, the terephthalate dianion is known to bond to metals to give one-dimensional chain complexes, e.g. in [Cu(bdc)(N-MeIm)2]n (where N-MeIm is N-methylimidazole) (Liu et al., 2005), [Zn(bdc)(H2O)2]n (Ding et al., 2003) and [[Co(bdc)(4-picoline)2(H2O)2](4-picoline)]n (Groeneman et al., 1999). On the other hand, in its bis-bidentate and combined modes of coordination, the terephthalate dianion can be found to chelate through the two carboxylate O atoms, as in [Cr(OH)(bdc)]4n[HO2C—C6H4—CO2H]3n (Millange et al., 2002), [Cu(L)(bdc)]n [L is N-(2-aminoethyl)-3-amino-1-propanol] (Mukherjee et al., 2004) and [Ni(bdc)(2,2'-bipy)(H2O)2]n (2,2'-bipy is 2,2'-bipyridine) (Go et al., 2004). However, in spite of this wealth of possibilities, only a few complexes of metal–nitroterephthalate systems have been reported to date. We have used the 2-nitroterephthalate dianion as a ligand, and have obtained the title novel six-coordinate 2-nitroterephthalato–zinc complex, (I). We describe here the structure of this one-dimensional metal–nitroterephthalate coordination polymer, with strong O—H···O interchain bonding leading to a three-dimensional supramolecular network.
The asymmetric unit in the structure of (I) comprises one Zn atom, one complete 2-nitroterephthalate dianion and four non-equivalent 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 of (I) is surrounded by an O6 donor set with octahedral geometry. The four equatorial sites are occupied by three O atoms from a monodentate carboxylate group (O1) and a bidentate carboxylate group [O3i and O4i; symmetry code: (i) -x, y + 1/2, -z + 1/2], and by one coordinated water molecule, O9. Atoms O7 and O8 from two other water molecules occupy two of the opposing apices of the octahedron. The Zn—Owater distances range from 2.051 (2) to 2.090 (2) Å and the Zn—O2-nitroterephthalate distances are in the range 1.987 (2)–2.253 (2) Å. Of these Zn—O distances, Zn—O3i and Zn—O4i are the longest. The cis O—Zn—O bond angles range from 85.32 (8) to 105.49 (9)°, except for O3i—Zn1—O4i, which is 58.80 (8)°. The trans O—Zn—O bond angles cover the range 156.60 (9)–172.19 (8)°. Thus, the coordination octahedron around the Zn atom is significantly distorted.
In the present structure, the versatility of the dianionic 2-nitroterephthalate ligand can be clearly seen. Mono- and bidentate chelating and bridging bonding modes are present. Atom O1 of the O1/C1/O2 carboxylate group has a monodentate mode, while atoms O3 and O4 of the O3/C8/O4 carboxylate group adopt a bidentate 1,2-chelating mode to the Zn atom. These adopt a bridging mode via the aromatic ring to connect two Zn atoms. The O—C—O angle for the monodentate carboxylate group (O1/C1/O2) is 127.5 (3)°, notably larger than the value of 120.8 (3)° for the chelating carboxylate group. The two C—O bond distances (O1—C1 and O2—C1) of the monodentate carboxylate group are 1.267 (4) and 1.232 (4) Å, respectively, while the two C—O bond distances (O3—C8 and O4—C8) of the chelating carboxylate group are 1.262 (4) and 1.259 (4) Å, respectively. This indicates that the mesomeric effect for the chelating carboxylate group is greater than that of the monodentate carboxylate group.
In the crystallographic c direction, perpendicular to the direction of chain propagation, neighbouring chains are linked together via O8—H8B···O3ii (part of a bifurcated hydrogen bond) and O7—H7A···O3iii hydrogen-bonded interactions (symmetry codes and geometric details in Table 2). This results in the Zn atoms stacking in a zigzag fashion along the c direction and the aryl rings of the 2-nitroterephthalate ligands stacking along the c direction, ca 3.93 Å apart. In this way, a two-dimensional layer is formed parallel to the bc plane (Fig. 2). Supramolecular connectivity within this layer is further enhanced by hydrogen bonds involving the uncoordinated water molecules (Table 2).
The three coordinated water molecules, a disordered water molecule and the nitro group (O5/N1/O6) also engage in hydrogen bonds (Table 2), which influence the conformation of the polymer. The strong hydrogen bond O8—H8A···O2v plays an important role (Brown, 1976) in the aggregation of the one-dimensional polymer through the formation of a 12-membered hydrogen-bonded R22(12) ring (Bernstein et al., 1995) between chains (Fig. 3a). Furthermore, the hydrogen bond O9—H9A···O4vi links each chain to its neighbour via an R22(8) grouping (Fig. 3a). The resulting supramolecular aggregation yields a zigzag stacking of the Zn atoms along the a direction. Also in the a direction, perpendicular to the direction of chain propagation, O9—H9B···O2iv hydrogen bonds link neighbouring chains together and complete a two-dimensional layer parallel to the crystallographic ab plane (Fig. 3b). Other hydrogen bonds, such as O8—H8B···O5, O10—H10B···O6, O10—H10A···O4iv and O10'—H11A···O4iv, involving free water molecules, further enhance the aggregation in this layer. Full details of all these hydrogen bonds, and their associated symmetry codes, are given in Table 2.