The novel title complex, {[Cu3(C8H3NO6)2(OH)2(H2O)6]·2H2O}n, has a one-dimensional polymeric double chain structure where the three Cu atoms are linked by μ2-OH and μ2-H2O groups, and these trinuclear centres are bridged by two 3-nitrophthalate ligands. The asymmetric unit contains one and a half crystallographically independent Cu atoms (one lying on a centre of inversion), both coordinated by six O atoms and exhibiting distorted octahedral coordination geometries, but with different coordination environments. Each 3-nitrophthalate ligand connects to three Cu atoms through two O atoms of one carboxylate group and one O atom of the nitro group. The remaining carboxylate group is free and is involved in intrachain hydrogen bonds, reinforcing the chain linkage.
Supporting information
CCDC reference: 718115
The addition of anhydrous sodium carbonate (0.53 g, 5 mmol) to a stirred
solution of copper nitrate hexahydrate (1.20 g, 4 mol) in water (20 ml)
produced a blue precipitate, which was filtered off and washed with distilled
water. The precipitate was subsequently added to a stirred solution of
3-nitrophthalic acid (0.53 g, 2.5 mol) in boiling water (15 ml) over a period
of 20 min. After filtration, slow evaporation over a period of two weeks at
room temperature yielded blue block-like crystals of (I).
All water H atoms were found in difference Fourier maps and were kept fixed
during refinement with O—H distances of 0.84–0.85 Å and Uiso(H)
equal to 1.2Ueq(O). H atoms of CH groups were idealized and treated
as riding, with C—H distances of 0.93 Å and Uiso(H) values of
1.2Ueq(C).
Data collection: CrystalClear (Rigaku/MSC, 2005); cell refinement: CrystalClear (Rigaku/MSC, 2005); data reduction: CrystalClear (Rigaku/MSC, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: SHELXTL (Sheldrick, 2008); software used to prepare material for publication: SHELXTL (Sheldrick, 2008).
Poly[[hexaaquadi-µ-hydroxido-bis(µ-3-nitrophthalato)tricopper(II)] dihydrate]
top
Crystal data top
[Cu3(C8H3NO6)2(OH)2(H2O)6]·2H2O | Z = 1 |
Mr = 786.99 | F(000) = 397 |
Triclinic, P1 | Dx = 2.072 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 7.2192 (14) Å | Cell parameters from 1826 reflections |
b = 8.3899 (17) Å | θ = 2.6–27.5° |
c = 11.191 (2) Å | µ = 2.61 mm−1 |
α = 74.81 (3)° | T = 133 K |
β = 84.38 (3)° | Block, blue |
γ = 74.77 (3)° | 0.16 × 0.12 × 0.08 mm |
V = 630.9 (2) Å3 | |
Data collection top
Rigaku Saturn diffractometer | 2192 independent reflections |
Radiation source: rotating anode | 1757 reflections with I > 2σ(I) |
Confocal monochromator | Rint = 0.051 |
Detector resolution: 27.482 pixels mm-1 | θmax = 25.0°, θmin = 2.6° |
ω scans | h = −7→8 |
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005) | k = −8→9 |
Tmin = 0.702, Tmax = 0.815 | l = −13→12 |
3616 measured reflections | |
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)] = 0.042 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.108 | H-atom parameters constrained |
S = 1.03 | w = 1/[σ2(Fo2) + (0.067P)2] where P = (Fo2 + 2Fc2)/3 |
2192 reflections | (Δ/σ)max < 0.001 |
196 parameters | Δρmax = 0.83 e Å−3 |
6 restraints | Δρmin = −0.69 e Å−3 |
Crystal data top
[Cu3(C8H3NO6)2(OH)2(H2O)6]·2H2O | γ = 74.77 (3)° |
Mr = 786.99 | V = 630.9 (2) Å3 |
Triclinic, P1 | Z = 1 |
a = 7.2192 (14) Å | Mo Kα radiation |
b = 8.3899 (17) Å | µ = 2.61 mm−1 |
c = 11.191 (2) Å | T = 133 K |
α = 74.81 (3)° | 0.16 × 0.12 × 0.08 mm |
β = 84.38 (3)° | |
Data collection top
Rigaku Saturn diffractometer | 2192 independent reflections |
Absorption correction: multi-scan (CrystalClear; Rigaku/MSC, 2005) | 1757 reflections with I > 2σ(I) |
Tmin = 0.702, Tmax = 0.815 | Rint = 0.051 |
3616 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.042 | 6 restraints |
wR(F2) = 0.108 | H-atom parameters constrained |
S = 1.03 | Δρmax = 0.83 e Å−3 |
2192 reflections | Δρmin = −0.69 e Å−3 |
196 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 | |
Cu1 | 0.5000 | 0.5000 | 0.5000 | 0.0093 (2) | |
Cu2 | 0.60502 (6) | 0.14889 (5) | 0.67727 (4) | 0.01014 (18) | |
O1 | 0.4137 (4) | 0.5396 (3) | 0.6626 (2) | 0.0140 (6) | |
O2 | 0.4923 (4) | 0.2840 (3) | 0.7968 (2) | 0.0133 (6) | |
O3 | 0.2545 (4) | 0.8884 (3) | 0.6656 (2) | 0.0141 (6) | |
O4 | 0.0364 (3) | 0.7545 (3) | 0.6431 (2) | 0.0136 (6) | |
N1 | −0.0760 (4) | 0.8992 (4) | 0.9138 (3) | 0.0134 (7) | |
O5 | −0.0914 (4) | 0.9901 (3) | 0.8074 (2) | 0.0186 (6) | |
O6 | −0.1828 (4) | 0.9354 (4) | 1.0003 (3) | 0.0224 (7) | |
C1 | 0.4125 (5) | 0.4405 (5) | 0.7685 (3) | 0.0122 (8) | |
C2 | 0.3040 (5) | 0.5173 (4) | 0.8683 (3) | 0.0108 (8) | |
C3 | 0.3238 (5) | 0.4248 (5) | 0.9919 (3) | 0.0124 (8) | |
H3 | 0.4059 | 0.3163 | 1.0102 | 0.015* | |
C4 | 0.2259 (5) | 0.4892 (5) | 1.0865 (3) | 0.0145 (8) | |
H4 | 0.2456 | 0.4267 | 1.1682 | 0.017* | |
C5 | 0.0972 (5) | 0.6478 (5) | 1.0605 (3) | 0.0138 (8) | |
H5A | 0.0278 | 0.6925 | 1.1239 | 0.017* | |
C6 | 0.0742 (5) | 0.7389 (4) | 0.9371 (3) | 0.0121 (8) | |
C7 | 0.1780 (5) | 0.6809 (4) | 0.8390 (3) | 0.0109 (8) | |
C8 | 0.1552 (5) | 0.7822 (4) | 0.7051 (3) | 0.0109 (8) | |
O7 | 0.2814 (3) | 0.6783 (3) | 0.4260 (2) | 0.0111 (5) | |
H7A | 0.2155 | 0.7125 | 0.4851 | 0.013* | |
H7B | 0.2210 | 0.6430 | 0.3807 | 0.013* | |
O8 | 0.3426 (3) | 0.2698 (3) | 0.5484 (2) | 0.0129 (6) | |
H8A | 0.3077 | 0.2192 | 0.5020 | 0.015* | |
O9 | 0.4909 (4) | −0.0296 (3) | 0.7909 (2) | 0.0156 (6) | |
H9A | 0.4176 | −0.0575 | 0.7500 | 0.019* | |
H9B | 0.4347 | 0.0290 | 0.8407 | 0.019* | |
O10 | 0.7143 (3) | −0.0160 (3) | 0.5746 (2) | 0.0129 (6) | |
H10A | 0.7214 | 0.0292 | 0.4970 | 0.015* | |
H10B | 0.8244 | −0.0745 | 0.6022 | 0.015* | |
O11 | 0.0155 (4) | 0.4078 (3) | 0.6559 (2) | 0.0160 (6) | |
H11A | 0.1077 | 0.3645 | 0.6117 | 0.019* | |
H11B | 0.0135 | 0.5114 | 0.6470 | 0.019* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Cu1 | 0.0098 (3) | 0.0093 (3) | 0.0082 (3) | 0.0007 (2) | 0.0008 (2) | −0.0048 (2) |
Cu2 | 0.0110 (3) | 0.0092 (3) | 0.0106 (3) | −0.00073 (18) | 0.00081 (18) | −0.00528 (18) |
O1 | 0.0163 (14) | 0.0147 (12) | 0.0091 (12) | −0.0003 (11) | 0.0006 (10) | −0.0036 (11) |
O2 | 0.0167 (13) | 0.0110 (12) | 0.0120 (12) | −0.0006 (10) | −0.0009 (10) | −0.0050 (10) |
O3 | 0.0164 (14) | 0.0142 (12) | 0.0139 (12) | −0.0047 (11) | 0.0006 (10) | −0.0066 (10) |
O4 | 0.0132 (13) | 0.0136 (12) | 0.0144 (12) | 0.0002 (10) | −0.0010 (10) | −0.0078 (10) |
N1 | 0.0116 (16) | 0.0165 (15) | 0.0167 (16) | −0.0031 (13) | 0.0038 (13) | −0.0138 (14) |
O5 | 0.0202 (15) | 0.0180 (13) | 0.0155 (14) | 0.0022 (11) | −0.0017 (11) | −0.0072 (11) |
O6 | 0.0207 (15) | 0.0249 (14) | 0.0209 (14) | −0.0003 (12) | 0.0063 (12) | −0.0124 (12) |
C1 | 0.0050 (17) | 0.0178 (17) | 0.0149 (18) | −0.0017 (14) | −0.0025 (14) | −0.0065 (15) |
C2 | 0.0099 (18) | 0.0142 (17) | 0.0109 (17) | −0.0039 (14) | −0.0012 (14) | −0.0064 (14) |
C3 | 0.0111 (18) | 0.0154 (17) | 0.0138 (18) | −0.0073 (15) | −0.0027 (14) | −0.0040 (15) |
C4 | 0.0159 (19) | 0.0206 (18) | 0.0096 (17) | −0.0070 (15) | 0.0006 (14) | −0.0057 (15) |
C5 | 0.015 (2) | 0.0185 (18) | 0.0129 (17) | −0.0076 (15) | 0.0041 (15) | −0.0114 (15) |
C6 | 0.0100 (19) | 0.0138 (17) | 0.0141 (17) | 0.0001 (14) | 0.0003 (14) | −0.0098 (15) |
C7 | 0.0098 (18) | 0.0146 (17) | 0.0116 (17) | −0.0054 (14) | 0.0007 (14) | −0.0069 (14) |
C8 | 0.0109 (11) | 0.0106 (10) | 0.0111 (10) | −0.0001 (8) | 0.0004 (8) | −0.0054 (8) |
O7 | 0.0106 (12) | 0.0130 (12) | 0.0117 (12) | −0.0021 (10) | 0.0008 (10) | −0.0080 (10) |
O8 | 0.0115 (13) | 0.0149 (12) | 0.0175 (13) | −0.0062 (10) | −0.0031 (11) | −0.0088 (11) |
O9 | 0.0194 (14) | 0.0159 (12) | 0.0138 (13) | −0.0049 (11) | 0.0009 (11) | −0.0080 (11) |
O10 | 0.0120 (13) | 0.0134 (12) | 0.0131 (12) | −0.0016 (10) | −0.0026 (10) | −0.0038 (10) |
O11 | 0.0172 (13) | 0.0157 (12) | 0.0160 (13) | −0.0006 (11) | 0.0052 (10) | −0.0111 (11) |
Geometric parameters (Å, º) top
Cu1—O7 | 1.944 (2) | C2—C3 | 1.398 (5) |
Cu1—O7i | 1.944 (2) | C2—C7 | 1.409 (5) |
Cu1—O1i | 1.948 (3) | C3—C4 | 1.366 (6) |
Cu1—O1 | 1.948 (3) | C3—H3 | 0.9300 |
Cu1—O8 | 2.408 (3) | C4—C5 | 1.386 (5) |
Cu1—O8i | 2.408 (3) | C4—H4 | 0.9300 |
Cu1—Cu2i | 3.0409 (12) | C5—C6 | 1.395 (5) |
Cu2—O7i | 1.916 (2) | C5—H5A | 0.9300 |
Cu2—O2 | 1.958 (3) | C6—C7 | 1.389 (5) |
Cu2—O10 | 1.984 (3) | C7—C8 | 1.518 (5) |
Cu2—O9 | 1.996 (3) | O7—Cu2i | 1.916 (2) |
Cu2—O8 | 2.336 (3) | O7—H7A | 0.8436 |
Cu2—O5ii | 2.603 (3) | O7—H7B | 0.8517 |
O1—C1 | 1.258 (4) | O8—H8A | 0.8431 |
O2—C1 | 1.256 (4) | O9—H9A | 0.8433 |
O3—C8 | 1.253 (4) | O9—H9B | 0.8435 |
O4—C8 | 1.256 (5) | O10—H10A | 0.8544 |
N1—O6 | 1.228 (4) | O10—H10B | 0.8549 |
N1—O5 | 1.232 (4) | O11—H11A | 0.8500 |
N1—C6 | 1.469 (4) | O11—H11B | 0.8457 |
C1—C2 | 1.489 (5) | | |
| | | |
O7—Cu1—O7i | 180.0 | O1—C1—C2 | 116.3 (3) |
O7—Cu1—O1i | 90.03 (11) | C3—C2—C7 | 119.7 (3) |
O7i—Cu1—O1i | 89.97 (11) | C3—C2—C1 | 119.7 (3) |
O7—Cu1—O1 | 89.97 (11) | C7—C2—C1 | 120.6 (3) |
O7i—Cu1—O1 | 90.03 (11) | C4—C3—C2 | 121.9 (3) |
O1i—Cu1—O1 | 180.0 | C4—C3—H3 | 119.1 |
O7—Cu1—O8 | 96.75 (10) | C2—C3—H3 | 119.1 |
O7i—Cu1—O8 | 83.25 (10) | C3—C4—C5 | 119.8 (3) |
O1i—Cu1—O8 | 91.97 (10) | C3—C4—H4 | 120.1 |
O1—Cu1—O8 | 88.03 (10) | C5—C4—H4 | 120.1 |
O7—Cu1—O8i | 83.25 (10) | C4—C5—C6 | 118.4 (4) |
O7i—Cu1—O8i | 96.75 (10) | C4—C5—H5A | 120.8 |
O1i—Cu1—O8i | 88.03 (10) | C6—C5—H5A | 120.8 |
O1—Cu1—O8i | 91.97 (10) | C7—C6—C5 | 123.3 (3) |
O8—Cu1—O8i | 180.0 | C7—C6—N1 | 120.4 (3) |
O7—Cu1—Cu2i | 37.71 (7) | C5—C6—N1 | 116.2 (3) |
O7i—Cu1—Cu2i | 142.29 (7) | C6—C7—C2 | 116.8 (3) |
O1i—Cu1—Cu2i | 75.43 (7) | C6—C7—C8 | 123.1 (3) |
O1—Cu1—Cu2i | 104.57 (7) | C2—C7—C8 | 120.1 (3) |
O8—Cu1—Cu2i | 130.90 (6) | O3—C8—O4 | 125.2 (3) |
O8i—Cu1—Cu2i | 49.10 (6) | O3—C8—C7 | 117.4 (3) |
O7i—Cu2—O2 | 94.14 (11) | O4—C8—C7 | 117.3 (3) |
O7i—Cu2—O10 | 93.43 (11) | Cu2i—O7—Cu1 | 103.95 (12) |
O2—Cu2—O10 | 172.00 (10) | Cu2i—O7—H7A | 111.3 |
O7i—Cu2—O9 | 177.67 (11) | Cu1—O7—H7A | 106.3 |
O2—Cu2—O9 | 84.26 (11) | Cu2i—O7—H7B | 108.7 |
O10—Cu2—O9 | 88.09 (11) | Cu1—O7—H7B | 111.1 |
O7i—Cu2—O8 | 85.83 (10) | H7A—O7—H7B | 114.9 |
O2—Cu2—O8 | 92.82 (10) | Cu2—O8—Cu1 | 79.72 (8) |
O10—Cu2—O8 | 90.30 (10) | Cu2—O8—H8A | 123.7 |
O9—Cu2—O8 | 95.92 (10) | Cu1—O8—H8A | 130.8 |
C1—O1—Cu1 | 132.5 (3) | Cu2—O9—H9A | 108.6 |
C1—O2—Cu2 | 124.7 (2) | Cu2—O9—H9B | 97.1 |
O6—N1—O5 | 122.9 (3) | H9A—O9—H9B | 115.1 |
O6—N1—C6 | 118.8 (3) | Cu2—O10—H10A | 114.4 |
O5—N1—C6 | 118.3 (3) | Cu2—O10—H10B | 108.3 |
O2—C1—O1 | 126.0 (4) | H10A—O10—H10B | 111.2 |
O2—C1—C2 | 117.7 (3) | H11A—O11—H11B | 108.8 |
| | | |
O7—Cu1—O1—C1 | 141.4 (3) | C5—C6—C7—C2 | 3.5 (5) |
O7i—Cu1—O1—C1 | −38.6 (3) | N1—C6—C7—C2 | −173.1 (3) |
O8—Cu1—O1—C1 | 44.6 (3) | C5—C6—C7—C8 | −178.7 (3) |
O8i—Cu1—O1—C1 | −135.4 (3) | N1—C6—C7—C8 | 4.7 (5) |
Cu2i—Cu1—O1—C1 | 176.5 (3) | C3—C2—C7—C6 | −2.1 (5) |
O7i—Cu2—O2—C1 | 41.4 (3) | C1—C2—C7—C6 | 176.4 (3) |
O9—Cu2—O2—C1 | −140.3 (3) | C3—C2—C7—C8 | −179.9 (3) |
O8—Cu2—O2—C1 | −44.6 (3) | C1—C2—C7—C8 | −1.4 (5) |
Cu2—O2—C1—O1 | −9.9 (5) | C6—C7—C8—O3 | 86.6 (4) |
Cu2—O2—C1—C2 | 169.3 (2) | C2—C7—C8—O3 | −95.7 (4) |
Cu1—O1—C1—O2 | 9.1 (6) | C6—C7—C8—O4 | −92.4 (4) |
Cu1—O1—C1—C2 | −170.1 (2) | C2—C7—C8—O4 | 85.2 (4) |
O2—C1—C2—C3 | 12.2 (5) | O1i—Cu1—O7—Cu2i | −65.68 (13) |
O1—C1—C2—C3 | −168.5 (3) | O1—Cu1—O7—Cu2i | 114.32 (13) |
O2—C1—C2—C7 | −166.3 (3) | O8—Cu1—O7—Cu2i | −157.67 (11) |
O1—C1—C2—C7 | 13.0 (5) | O8i—Cu1—O7—Cu2i | 22.33 (11) |
C7—C2—C3—C4 | −0.9 (6) | O7i—Cu2—O8—Cu1 | −18.10 (9) |
C1—C2—C3—C4 | −179.4 (3) | O2—Cu2—O8—Cu1 | 75.85 (9) |
C2—C3—C4—C5 | 2.6 (6) | O10—Cu2—O8—Cu1 | −111.52 (9) |
C3—C4—C5—C6 | −1.2 (5) | O9—Cu2—O8—Cu1 | 160.37 (9) |
C4—C5—C6—C7 | −2.0 (6) | O7—Cu1—O8—Cu2 | −162.09 (9) |
C4—C5—C6—N1 | 174.8 (3) | O7i—Cu1—O8—Cu2 | 17.91 (9) |
O6—N1—C6—C7 | 170.1 (4) | O1i—Cu1—O8—Cu2 | 107.65 (9) |
O5—N1—C6—C7 | −8.6 (5) | O1—Cu1—O8—Cu2 | −72.35 (9) |
O6—N1—C6—C5 | −6.8 (5) | Cu2i—Cu1—O8—Cu2 | 180.0 |
O5—N1—C6—C5 | 174.5 (3) | | |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x+1, y−1, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O11—H11B···O4 | 0.85 | 2.08 | 2.918 (4) | 172 |
O11—H11A···O8 | 0.85 | 1.83 | 2.665 (4) | 166 |
O10—H10B···O4ii | 0.85 | 1.80 | 2.631 (3) | 163 |
O10—H10A···O3i | 0.85 | 1.78 | 2.632 (3) | 177 |
O9—H9A···O3iii | 0.84 | 1.79 | 2.634 (4) | 178 |
O9—H9B···O2 | 0.84 | 2.21 | 2.652 (3) | 113 |
O8—H8A···O10iv | 0.84 | 2.15 | 2.951 (4) | 160 |
O7—H7B···O11v | 0.85 | 1.97 | 2.739 (4) | 150 |
O7—H7A···O4 | 0.84 | 2.14 | 2.969 (4) | 170 |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x+1, y−1, z; (iii) x, y−1, z; (iv) −x+1, −y, −z+1; (v) −x, −y+1, −z+1. |
Experimental details
Crystal data |
Chemical formula | [Cu3(C8H3NO6)2(OH)2(H2O)6]·2H2O |
Mr | 786.99 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 133 |
a, b, c (Å) | 7.2192 (14), 8.3899 (17), 11.191 (2) |
α, β, γ (°) | 74.81 (3), 84.38 (3), 74.77 (3) |
V (Å3) | 630.9 (2) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 2.61 |
Crystal size (mm) | 0.16 × 0.12 × 0.08 |
|
Data collection |
Diffractometer | Rigaku Saturn diffractometer |
Absorption correction | Multi-scan (CrystalClear; Rigaku/MSC, 2005) |
Tmin, Tmax | 0.702, 0.815 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3616, 2192, 1757 |
Rint | 0.051 |
(sin θ/λ)max (Å−1) | 0.595 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.042, 0.108, 1.03 |
No. of reflections | 2192 |
No. of parameters | 196 |
No. of restraints | 6 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.83, −0.69 |
Selected bond lengths (Å) topCu1—O7 | 1.944 (2) | Cu2—O10 | 1.984 (3) |
Cu1—O1 | 1.948 (3) | Cu2—O9 | 1.996 (3) |
Cu1—O8 | 2.408 (3) | Cu2—O8 | 2.336 (3) |
Cu2—O7i | 1.916 (2) | Cu2—O5ii | 2.603 (3) |
Cu2—O2 | 1.958 (3) | | |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x+1, y−1, z. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O11—H11B···O4 | 0.85 | 2.08 | 2.918 (4) | 172.3 |
O11—H11A···O8 | 0.85 | 1.83 | 2.665 (4) | 165.6 |
O10—H10B···O4ii | 0.85 | 1.80 | 2.631 (3) | 162.7 |
O10—H10A···O3i | 0.85 | 1.78 | 2.632 (3) | 176.6 |
O9—H9A···O3iii | 0.84 | 1.79 | 2.634 (4) | 177.9 |
O9—H9B···O2 | 0.844 | 2.207 | 2.652 (3) | 112.9 |
O8—H8A···O10iv | 0.84 | 2.15 | 2.951 (4) | 159.7 |
O7—H7B···O11v | 0.85 | 1.97 | 2.739 (4) | 150.0 |
O7—H7A···O4 | 0.84 | 2.14 | 2.969 (4) | 169.5 |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) x+1, y−1, z; (iii) x, y−1, z; (iv) −x+1, −y, −z+1; (v) −x, −y+1, −z+1. |
In constructing coordination polymers, aromatic dicarboxylic acids, such as o-phthalic, m-phthalic and p-phthalic acids, have been shown to produce a great variety of interesting structures (Zheng et al., 2002; Wang et al., 2001; Wan et al., 2003, 2002; Hong & Do, 1997; Eddaoudi et al., 2001). Among these isomeric forms of phthalate, the o-phthalate ligand, with two carboxylate groups in ortho-positions, can bind metal ions in a diversity of bonding modes and thus lead to the formation of interesting network architectures (Baca et al., 2004).
On the other hand, if an electron-withdrawing nitro group is also present in the ligand, it can not only coordinate metal ions in a variety of ways but also act as a hydrogen-bond acceptor, taking part in the formation of polymeric networks (Liu et al., 2006). Recently, a series of lanthanide and transition metal complexes with 3-nitrophthalic acid were successfully obtained; however, in most of these complexes the 3-nitrophthalic ligands are coordinated to the metal ions with two carboxylate groups (Deng, Liu et al., 2007; Deng, Wang et al., 2007; Huang et al., 2007; Song et al., 2007). In this paper, we used 3-nitrophthalic acid as a rigid ligand and synthesized the one-dimensional coordination polymer [Cu3(C8H3NO6)2(OH)2(H2O)6]n.2nH2O, in which the nitro group of the 3-nitrophthalic anion is also coordinated to the metal ion.
The title complex presents a double chain structure. There are one and a half crystallographically independent Cu atoms in the asymmetric unit, (one of them lies at an inversion centre) one complete 3-nitrophthalic anion, one hydroxyl group and three coordinated water molecules together with a free water molecule, and Fig. 1 shows the full coordination environments of the Cu atoms in a symmetry-expanded view.
In the complex, the Cu atoms are both six-coordinated, but they have two different coordination environments. Atom Cu1 lies on the inversion centre and is coordinated to an O6 donor set. Four equatorial sites are occupied by four O atoms from two monodentate carboxylate groups [O1 and O1i; symmetry code: (i) -x + 1, -y + 1, -z + 1] of two equivalent 3-nitrophthalic anions and two coordinated water molecules (O7 and O7i). The Cu1—Ocarboxylate distances are both 1.948 (3) Å and the Cu1—Owater distances are both 1.944 (2) Å. The axial sites are completed by two O atoms from two hydroxyl groups, and the Cu1—Ohydroxyl distances are both 2.408 (3) Å. For atom Cu2, the six O atoms belong to three water molecules, one carboxylate group of one 3-nitrophthalate anion, one nitro group of another 3-nitrophthalate anion and one hydroxyl group. The Cu2—Owater distances are in the range 1.916 (2)–1.996 (3) Å, the Cu2—Ocarboxylate distance is 1.958 (3) Å, the Cu2—Ohydroxyl distance is 2.603 (3) Å and the Cu2—Onitro distance is 2.603 (3) Å, which is longer than normal Cu—O bond lengths. For both cations the coordination environment is a significantly distorted octahedron.
In the present structure, there is only one type of 3-nitrophthalate anion, which adopts 1,3-bridging and monodentate modes to coordinate with Cu atoms (see scheme). Atom O5 of the nitro group adopts a monodentate mode to connect with one Cu atom, and atoms O1 and O2 of one carboxylate group adopt a 1,3-bridging mode to link two Cu atoms; the other carboxylate group of 3-nitrophthalic anion is free.
This is the first example of this type of coordination mode for the 3-nitrophthalate anion. There is a previously reported structure with a binding nitro group [K2Cu(NPA)2(H2O)4]n (H2NPA is 3-nitrophthalic acid; Shen et al., 2006), but in the latter, the 3-nitrophthalate ligand coordinates to K and Cu ions with the nitro and both carboxylate groups, while in the title complex, the 3-nitrophthalate ligand coordinates to Cu ions with only one carboxylate group and the nitro group, the other carboxylate group being free. To the best of our knowledge, this type of coordination mode for the 3-nitrophthalate ligand has not been reported in the literature
In this way, a one-dimensional polymeric double chain structure with a trinuclear centre builds up, where the cations are linked by µ2-OH and µ2-H2O groups and further bridged by two 3-nitrophthalate ligands (Fig. 2). The Cu1···Cu2 separation in the trinuclear unit is 3.041 (1) Å, which could be considered a weak interaction since it is in the range of the sum of the van der Waals radii of two Cu ions.
In the double chain, 3-nitrophthalic anions interconnect with Cu atoms, forming two different types of ring – a six-membered one containing two Cu atoms and a 19-membered one containing four Cu atoms – which are alternate along the infinite one-dimensional array. The chains are further stabilized by intra-chain hydrogen bonds involving the free carboxylate groups as acceptors and coordinated water molecules or hydroxyl groups as donors (Table 2).
Fig. 3 shows a view of the packing of the title compound. There are a number of distinct hydrogen-bond interactions involving the ligands, both intra-chain (reinforcing the chain linkage) and inter-chain (assembling these one-dimensional chains into a three-dimensional network structure). Free water molecules (O11) reside between layers and also enter into hydrogen bonding with the free carboxylate group (O3), coordinated water molecules (O7) and the hydroxyl group (O8), further stabilizing the three-dimensional supramolecular network.