Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S160053680703173X/kj2057sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S160053680703173X/kj2057Isup2.hkl |
CCDC reference: 626651
Cobalt chlorine hexahydrate (0.119 g, 0.5 mmol), and 5-aminoisophthalic acid (0.0905 g, 0.5 mmol) were dissolved in water (9 ml). The solution was placed in a 15-ml Teflon-lined, stainless-steel, Parr bomb. The bomb was heated at 433 K for 6 days. The cooled-down mixture yielded light red crystals; these were washed with water and then dried in air (yield ca 70%, based on Co).
The water H atoms were located on difference Fourier maps; their coordinates and isotropic displacement parameters were refined freely. All other H atoms were positioned geometrically and refined with a riding model, with C—H distances of 0.95 (aromatic) Å, N—H distances of 0.92 Å, and with Uiso(H) = 1.2Ueq(C & N).
In recent years, a large number of metal-organic compounds have been prepared because of the fascinating structural and topological features of these compounds and their potential applications as functional materials, such as catalysts, optical materials and molecule-based magnets (Hagrman et al., 1999; Moulton & Zaworotko, 2001; Janiak, 2003). 5-aminoisophthalic acid (AIP) (Dobson et al., 1998), a polydentate organic ligand containing an amino group and two carboxyl groups, can be used as a bridging and/or terminal ligand. In this field, studies have been focused on organic-inorganic hybrid materials containing N-donor rigid heteroaromatic ligands, such as pyrazine or 4,4' –bipyridine. However, much less work has been carried out to investigate transition metal polymers containing aminobenzoic acid ligands. Using AIP, we have hydrothermally prepared the title compound, [Co(AIP) (H2O)2]n. The title complex consists of one Co(II) cation, one 5-aminoisophthalate anion and two coordinated water molecules (Fig. 1). Each AIP ligand employs its two carboxylate groups and one amino group to coordinate to three different metal centers. Each CoII center possesses a distorted six-coordinated octahedral geometry, defined by three carboxyl oxygen atoms, one from a monodentate and two from a 1,3-bidentate AIP2- ligands, one nitrogen atom from the third 5-aminoisophthalate anion and two aqua ligands. The mean Co—O (carboxyl) bond distance is 2.092 (18) Å, which is slightly shorter than that in [Co(C8NH5O4)(H2O)]n (2.109 (2) Å) (Wu et al., 2002). This difference is probably attributed to the different coordination modes of the ligands. The most interesting feature is that the AIP ligands link cobalt centers in different ways to produces two different subrings A and B, which are both 14-membered rings located on an inversion centre, with Co—Co distances of 7.917 (3) and 7.689 (3) Å, respectively. THe difference between the rings is that the A ring is closed by bidentate carboxylate groups and the B ring by monodentate carboxylate groups. Together they form an open railroad-like framework polymer, running in the c direction. Each linear polymer is connected into a three-dimensional supramolecular network by intermolecular hydrogen bonds among aqua ligands, the oxygen atoms of carboxylate groups and amino groups (Table 2).
For related literature, see: Dobson & Gerkin (1998); Hagrman et al. (1999); Janiak (2003); Moulton & Zaworotko (2001); Wu et al. (2002).
Data collection: RAPID-AUTO (Rigaku, 2004); cell refinement: RAPID-AUTO; data reduction: RAPID-AUTO; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997a); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997a); molecular graphics: SHELXTL (Sheldrick, 1997b); software used to prepare material for publication: SHELXTL.
| Fig. 1. A view of (I), showing 30% probability displacement ellipsoids. Symmetry codes:(i)-x + 1,-y + 1,-z + 2; (ii) -x + 1,-y + 1,-z + 1. |
[Co(C8H5NO4)(H2O)2] | Z = 2 |
Mr = 274.10 | F(000) = 278 |
Triclinic, P1 | Dx = 1.969 Mg m−3 |
a = 6.4168 (4) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 8.0919 (4) Å | Cell parameters from 3976 reflections |
c = 10.1493 (7) Å | θ = 3.3–27.5° |
α = 113.184 (1)° | µ = 1.87 mm−1 |
β = 99.946 (3)° | T = 153 K |
γ = 98.995 (2)° | PRISM, green |
V = 462.28 (5) Å3 | 0.15 × 0.13 × 0.10 mm |
Rigaku R-AXIS RAPID diffractometer | 2110 independent reflections |
Radiation source: Rotating Anode | 1854 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.027 |
ω scans | θmax = 27.5°, θmin = 3.3° |
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996) | h = −8→8 |
Tmin = 0.767, Tmax = 0.835 | k = −10→10 |
4523 measured reflections | l = −13→13 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.032 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.096 | w = 1/[σ2(Fo2) + (0.0586P)2 + 0.466P] where P = (Fo2 + 2Fc2)/3 |
S = 1.01 | (Δ/σ)max = 0.001 |
2110 reflections | Δρmax = 0.55 e Å−3 |
162 parameters | Δρmin = −0.75 e Å−3 |
0 restraints | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.007 (1) |
[Co(C8H5NO4)(H2O)2] | γ = 98.995 (2)° |
Mr = 274.10 | V = 462.28 (5) Å3 |
Triclinic, P1 | Z = 2 |
a = 6.4168 (4) Å | Mo Kα radiation |
b = 8.0919 (4) Å | µ = 1.87 mm−1 |
c = 10.1493 (7) Å | T = 153 K |
α = 113.184 (1)° | 0.15 × 0.13 × 0.10 mm |
β = 99.946 (3)° |
Rigaku R-AXIS RAPID diffractometer | 2110 independent reflections |
Absorption correction: empirical (using intensity measurements) (SADABS; Sheldrick, 1996) | 1854 reflections with I > 2σ(I) |
Tmin = 0.767, Tmax = 0.835 | Rint = 0.027 |
4523 measured reflections |
R[F2 > 2σ(F2)] = 0.032 | 0 restraints |
wR(F2) = 0.096 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.01 | Δρmax = 0.55 e Å−3 |
2110 reflections | Δρmin = −0.75 e Å−3 |
162 parameters |
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. |
x | y | z | Uiso*/Ueq | ||
Co | 0.20196 (5) | 0.75115 (5) | 0.80493 (3) | 0.01298 (14) | |
O1 | 0.6666 (3) | 0.2413 (3) | 0.9957 (2) | 0.0187 (4) | |
O2 | 0.9520 (3) | 0.2510 (3) | 0.8966 (2) | 0.0244 (4) | |
O3 | 0.8351 (3) | 0.2502 (3) | 0.4037 (2) | 0.0201 (4) | |
O4 | 0.5073 (3) | 0.2130 (3) | 0.2718 (2) | 0.0187 (4) | |
O5 | 0.2461 (3) | 1.0316 (3) | 0.9070 (2) | 0.0218 (4) | |
O6 | −0.1152 (3) | 0.7068 (3) | 0.8195 (2) | 0.0213 (4) | |
N | 0.1401 (4) | 0.4592 (3) | 0.7069 (2) | 0.0165 (4) | |
H0A | 0.0745 | 0.4180 | 0.7659 | 0.020* | |
H0B | 0.0389 | 0.4155 | 0.6172 | 0.020* | |
C1 | 0.3142 (4) | 0.3725 (4) | 0.6807 (3) | 0.0166 (5) | |
C2 | 0.4366 (4) | 0.3411 (4) | 0.7907 (3) | 0.0184 (5) | |
H2 | 0.3983 | 0.3718 | 0.8823 | 0.022* | |
C3 | 0.6145 (4) | 0.2655 (4) | 0.7693 (3) | 0.0164 (5) | |
C4 | 0.6708 (4) | 0.2196 (4) | 0.6345 (3) | 0.0171 (5) | |
H4 | 0.7907 | 0.1656 | 0.6182 | 0.021* | |
C5 | 0.5498 (4) | 0.2536 (4) | 0.5241 (3) | 0.0171 (5) | |
C6 | 0.3705 (4) | 0.3267 (4) | 0.5456 (3) | 0.0169 (5) | |
H6 | 0.2857 | 0.3456 | 0.4687 | 0.020* | |
C7 | 0.7566 (4) | 0.2477 (3) | 0.8947 (3) | 0.0168 (5) | |
C8 | 0.6319 (4) | 0.2345 (4) | 0.3918 (3) | 0.0162 (5) | |
H5A | 0.150 (7) | 1.097 (6) | 0.873 (5) | 0.047 (12)* | |
H5B | 0.373 (9) | 1.097 (7) | 0.930 (6) | 0.068 (16)* | |
H6A | −0.227 (7) | 0.764 (6) | 0.792 (5) | 0.046 (11)* | |
H6B | −0.093 (8) | 0.719 (6) | 0.910 (5) | 0.051 (13)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Co | 0.0108 (2) | 0.0199 (2) | 0.0113 (2) | 0.00718 (13) | 0.00536 (13) | 0.00760 (15) |
O1 | 0.0169 (9) | 0.0289 (10) | 0.0139 (9) | 0.0070 (8) | 0.0050 (7) | 0.0119 (8) |
O2 | 0.0179 (10) | 0.0403 (12) | 0.0225 (10) | 0.0142 (9) | 0.0086 (8) | 0.0171 (10) |
O3 | 0.0170 (9) | 0.0317 (11) | 0.0153 (9) | 0.0092 (8) | 0.0066 (7) | 0.0119 (9) |
O4 | 0.0155 (9) | 0.0282 (10) | 0.0154 (9) | 0.0086 (8) | 0.0066 (7) | 0.0101 (8) |
O5 | 0.0183 (10) | 0.0240 (10) | 0.0248 (10) | 0.0088 (8) | 0.0079 (8) | 0.0100 (9) |
O6 | 0.0144 (9) | 0.0321 (11) | 0.0203 (10) | 0.0091 (8) | 0.0076 (8) | 0.0116 (9) |
N | 0.0137 (10) | 0.0207 (11) | 0.0157 (10) | 0.0061 (8) | 0.0050 (8) | 0.0075 (9) |
C1 | 0.0157 (12) | 0.0180 (12) | 0.0171 (12) | 0.0051 (10) | 0.0069 (10) | 0.0071 (11) |
C2 | 0.0170 (12) | 0.0230 (12) | 0.0175 (12) | 0.0055 (10) | 0.0076 (10) | 0.0096 (11) |
C3 | 0.0167 (12) | 0.0198 (12) | 0.0141 (12) | 0.0050 (10) | 0.0056 (10) | 0.0079 (11) |
C4 | 0.0157 (12) | 0.0179 (12) | 0.0202 (13) | 0.0071 (10) | 0.0072 (10) | 0.0087 (11) |
C5 | 0.0175 (12) | 0.0209 (12) | 0.0135 (12) | 0.0043 (10) | 0.0074 (10) | 0.0068 (11) |
C6 | 0.0172 (12) | 0.0197 (12) | 0.0148 (12) | 0.0054 (10) | 0.0045 (10) | 0.0080 (11) |
C7 | 0.0194 (13) | 0.0172 (12) | 0.0169 (12) | 0.0076 (10) | 0.0069 (10) | 0.0085 (11) |
C8 | 0.0174 (12) | 0.0186 (12) | 0.0144 (12) | 0.0064 (10) | 0.0046 (10) | 0.0081 (11) |
Co—O1i | 2.0266 (18) | O6—H6B | 0.86 (5) |
Co—O5 | 2.037 (2) | N—C1 | 1.418 (3) |
Co—O6 | 2.0516 (19) | N—H0A | 0.9200 |
Co—O3ii | 2.0848 (18) | N—H0B | 0.9200 |
Co—N | 2.109 (2) | C1—C2 | 1.382 (4) |
Co—O4ii | 2.1631 (18) | C1—C6 | 1.401 (4) |
Co—C8ii | 2.452 (3) | C2—C3 | 1.387 (4) |
O1—C7 | 1.274 (3) | C2—H2 | 0.9500 |
O1—Coi | 2.0266 (18) | C3—C4 | 1.397 (4) |
O2—C7 | 1.246 (3) | C3—C7 | 1.503 (3) |
O3—C8 | 1.270 (3) | C4—C5 | 1.394 (4) |
O3—Coii | 2.0848 (18) | C4—H4 | 0.9500 |
O4—C8 | 1.267 (3) | C5—C6 | 1.385 (4) |
O4—Coii | 2.1632 (18) | C5—C8 | 1.487 (3) |
O5—H5A | 0.98 (4) | C6—H6 | 0.9500 |
O5—H5B | 0.84 (6) | C8—Coii | 2.452 (3) |
O6—H6A | 0.97 (4) | ||
O1i—Co—O5 | 88.76 (8) | Co—N—H0A | 107.3 |
O1i—Co—O6 | 95.54 (8) | C1—N—H0B | 107.3 |
O5—Co—O6 | 91.77 (8) | Co—N—H0B | 107.3 |
O1i—Co—O3ii | 162.55 (8) | H0A—N—H0B | 106.9 |
O5—Co—O3ii | 92.15 (8) | C2—C1—C6 | 119.4 (2) |
O6—Co—O3ii | 101.84 (8) | C2—C1—N | 120.4 (2) |
O1i—Co—N | 89.82 (8) | C6—C1—N | 120.1 (2) |
O5—Co—N | 176.15 (8) | C1—C2—C3 | 121.0 (2) |
O6—Co—N | 84.80 (9) | C1—C2—H2 | 119.5 |
O3ii—Co—N | 90.27 (8) | C3—C2—H2 | 119.5 |
O1i—Co—O4ii | 100.38 (7) | C2—C3—C4 | 119.7 (2) |
O5—Co—O4ii | 90.18 (8) | C2—C3—C7 | 120.1 (2) |
O6—Co—O4ii | 163.99 (8) | C4—C3—C7 | 120.1 (2) |
O3ii—Co—O4ii | 62.20 (7) | C5—C4—C3 | 119.6 (2) |
N—Co—O4ii | 93.60 (8) | C5—C4—H4 | 120.2 |
O1i—Co—C8ii | 131.37 (8) | C3—C4—H4 | 120.2 |
O5—Co—C8ii | 92.79 (8) | C6—C5—C4 | 120.3 (2) |
O6—Co—C8ii | 132.92 (9) | C6—C5—C8 | 120.0 (2) |
O3ii—Co—C8ii | 31.18 (8) | C4—C5—C8 | 119.2 (2) |
N—Co—C8ii | 90.83 (8) | C5—C6—C1 | 120.0 (2) |
O4ii—Co—C8ii | 31.08 (8) | C5—C6—H6 | 120.0 |
C7—O1—Coi | 130.14 (17) | C1—C6—H6 | 120.0 |
C8—O3—Coii | 90.60 (15) | O2—C7—O1 | 125.6 (2) |
C8—O4—Coii | 87.15 (15) | O2—C7—C3 | 118.7 (2) |
Co—O5—H5A | 123 (3) | O1—C7—C3 | 115.7 (2) |
Co—O5—H5B | 117 (4) | O4—C8—O3 | 119.8 (2) |
H5A—O5—H5B | 106 (4) | O4—C8—C5 | 121.9 (2) |
Co—O6—H6A | 128 (3) | O3—C8—C5 | 118.2 (2) |
Co—O6—H6B | 99 (3) | O4—C8—Coii | 61.77 (13) |
H6A—O6—H6B | 114 (4) | O3—C8—Coii | 58.23 (13) |
C1—N—Co | 120.08 (17) | C5—C8—Coii | 171.81 (19) |
C1—N—H0A | 107.3 | ||
O1i—Co—N—C1 | −74.77 (19) | C2—C1—C6—C5 | −1.1 (4) |
O6—Co—N—C1 | −170.35 (19) | N—C1—C6—C5 | 175.6 (2) |
O3ii—Co—N—C1 | 87.78 (19) | Coi—O1—C7—O2 | 3.9 (4) |
O4ii—Co—N—C1 | 25.62 (19) | Coi—O1—C7—C3 | −171.81 (17) |
C8ii—Co—N—C1 | 56.61 (19) | C2—C3—C7—O2 | −152.1 (3) |
Co—N—C1—C2 | 86.4 (3) | C4—C3—C7—O2 | 22.9 (4) |
Co—N—C1—C6 | −90.3 (3) | C2—C3—C7—O1 | 23.9 (4) |
C6—C1—C2—C3 | 0.2 (4) | C4—C3—C7—O1 | −161.1 (2) |
N—C1—C2—C3 | −176.5 (2) | Coii—O4—C8—O3 | −4.7 (2) |
C1—C2—C3—C4 | −0.2 (4) | Coii—O4—C8—C5 | 171.5 (2) |
C1—C2—C3—C7 | 174.8 (2) | Coii—O3—C8—O4 | 4.8 (3) |
C2—C3—C4—C5 | 1.2 (4) | Coii—O3—C8—C5 | −171.5 (2) |
C7—C3—C4—C5 | −173.8 (2) | C6—C5—C8—O4 | −27.7 (4) |
C3—C4—C5—C6 | −2.2 (4) | C4—C5—C8—O4 | 160.3 (2) |
C3—C4—C5—C8 | 169.8 (2) | C6—C5—C8—O3 | 148.5 (3) |
C4—C5—C6—C1 | 2.1 (4) | C4—C5—C8—O3 | −23.4 (4) |
C8—C5—C6—C1 | −169.8 (2) |
Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) −x+1, −y+1, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
N—H0A···O2iii | 0.92 | 2.38 | 3.275 (3) | 165 |
N—H0B···O3iii | 0.92 | 2.09 | 2.991 (3) | 165 |
O5—H5B···O1iv | 0.84 (6) | 1.90 (6) | 2.738 (3) | 175 (5) |
O5—H5A···O2v | 0.98 (4) | 1.89 (5) | 2.802 (3) | 154 (4) |
O6—H6B···O2i | 0.86 (5) | 1.92 (5) | 2.755 (3) | 162 (4) |
O6—H6A···O4vi | 0.97 (4) | 1.87 (5) | 2.791 (3) | 158 (4) |
Symmetry codes: (i) −x+1, −y+1, −z+2; (iii) x−1, y, z; (iv) x, y+1, z; (v) x−1, y+1, z; (vi) −x, −y+1, −z+1. |
Experimental details
Crystal data | |
Chemical formula | [Co(C8H5NO4)(H2O)2] |
Mr | 274.10 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 153 |
a, b, c (Å) | 6.4168 (4), 8.0919 (4), 10.1493 (7) |
α, β, γ (°) | 113.184 (1), 99.946 (3), 98.995 (2) |
V (Å3) | 462.28 (5) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 1.87 |
Crystal size (mm) | 0.15 × 0.13 × 0.10 |
Data collection | |
Diffractometer | Rigaku R-AXIS RAPID |
Absorption correction | Empirical (using intensity measurements) (SADABS; Sheldrick, 1996) |
Tmin, Tmax | 0.767, 0.835 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 4523, 2110, 1854 |
Rint | 0.027 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.032, 0.096, 1.01 |
No. of reflections | 2110 |
No. of parameters | 162 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.55, −0.75 |
Computer programs: RAPID-AUTO (Rigaku, 2004), RAPID-AUTO, SHELXS97 (Sheldrick, 1997a), SHELXL97 (Sheldrick, 1997a), SHELXTL (Sheldrick, 1997b), SHELXTL.
Co—O1i | 2.0266 (18) | Co—O3ii | 2.0848 (18) |
Co—O5 | 2.037 (2) | Co—N | 2.109 (2) |
Co—O6 | 2.0516 (19) | Co—O4ii | 2.1631 (18) |
O1i—Co—O5 | 88.76 (8) | O5—Co—N | 176.15 (8) |
O1i—Co—O6 | 95.54 (8) | O6—Co—N | 84.80 (9) |
O5—Co—O6 | 91.77 (8) | O3ii—Co—N | 90.27 (8) |
O1i—Co—O3ii | 162.55 (8) | O1i—Co—O4ii | 100.38 (7) |
O5—Co—O3ii | 92.15 (8) | O5—Co—O4ii | 90.18 (8) |
O6—Co—O3ii | 101.84 (8) | O6—Co—O4ii | 163.99 (8) |
O1i—Co—N | 89.82 (8) | O3ii—Co—O4ii | 62.20 (7) |
Symmetry codes: (i) −x+1, −y+1, −z+2; (ii) −x+1, −y+1, −z+1. |
D—H···A | D—H | H···A | D···A | D—H···A |
N—H0A···O2iii | 0.92 | 2.38 | 3.275 (3) | 165.4 |
N—H0B···O3iii | 0.92 | 2.09 | 2.991 (3) | 164.5 |
O5—H5B···O1iv | 0.84 (6) | 1.90 (6) | 2.738 (3) | 175 (5) |
O5—H5A···O2v | 0.98 (4) | 1.89 (5) | 2.802 (3) | 154 (4) |
O6—H6B···O2i | 0.86 (5) | 1.92 (5) | 2.755 (3) | 162 (4) |
O6—H6A···O4vi | 0.97 (4) | 1.87 (5) | 2.791 (3) | 158 (4) |
Symmetry codes: (i) −x+1, −y+1, −z+2; (iii) x−1, y, z; (iv) x, y+1, z; (v) x−1, y+1, z; (vi) −x, −y+1, −z+1. |
In recent years, a large number of metal-organic compounds have been prepared because of the fascinating structural and topological features of these compounds and their potential applications as functional materials, such as catalysts, optical materials and molecule-based magnets (Hagrman et al., 1999; Moulton & Zaworotko, 2001; Janiak, 2003). 5-aminoisophthalic acid (AIP) (Dobson et al., 1998), a polydentate organic ligand containing an amino group and two carboxyl groups, can be used as a bridging and/or terminal ligand. In this field, studies have been focused on organic-inorganic hybrid materials containing N-donor rigid heteroaromatic ligands, such as pyrazine or 4,4' –bipyridine. However, much less work has been carried out to investigate transition metal polymers containing aminobenzoic acid ligands. Using AIP, we have hydrothermally prepared the title compound, [Co(AIP) (H2O)2]n. The title complex consists of one Co(II) cation, one 5-aminoisophthalate anion and two coordinated water molecules (Fig. 1). Each AIP ligand employs its two carboxylate groups and one amino group to coordinate to three different metal centers. Each CoII center possesses a distorted six-coordinated octahedral geometry, defined by three carboxyl oxygen atoms, one from a monodentate and two from a 1,3-bidentate AIP2- ligands, one nitrogen atom from the third 5-aminoisophthalate anion and two aqua ligands. The mean Co—O (carboxyl) bond distance is 2.092 (18) Å, which is slightly shorter than that in [Co(C8NH5O4)(H2O)]n (2.109 (2) Å) (Wu et al., 2002). This difference is probably attributed to the different coordination modes of the ligands. The most interesting feature is that the AIP ligands link cobalt centers in different ways to produces two different subrings A and B, which are both 14-membered rings located on an inversion centre, with Co—Co distances of 7.917 (3) and 7.689 (3) Å, respectively. THe difference between the rings is that the A ring is closed by bidentate carboxylate groups and the B ring by monodentate carboxylate groups. Together they form an open railroad-like framework polymer, running in the c direction. Each linear polymer is connected into a three-dimensional supramolecular network by intermolecular hydrogen bonds among aqua ligands, the oxygen atoms of carboxylate groups and amino groups (Table 2).