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The title compound, [Cd(C6H4NO2)2(H2O)2]n, forms a one-dimensional chain structure based on a Cd atom with approximate pentagonal bipyramidal coordination geometry and two nicotinate ligands in different coordination modes. One acts as a tridentate ligand, chelating one Cd atom through the carboxyl­ate group while simultaneously binding to a second symmetry-related Cd atom through the pyridine N atom; the other acts only as a bidentate ligand through its carboxyl­ate group. Hydro­gen bonds utilizing the coordinated water mol­ecules, uncoordinated nitro­gen and carboxyl­ate O atoms as acceptors link the chains.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104010558/ga1055sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270104010558/ga1055Isup2.hkl
Contains datablock I

CCDC reference: 248132

Comment top

There has been considerable recent interest in the design and synthesis of supramolecular complexes because of their novel structural architectures and favorable properties, which favor applications such as ion exchange, adsorption, nonlinear optics and magnetism (Noro et al., 2000; Yaghi et al., 1998). Some organic N-donors, such as bipyridine or related species, are often chosen to fabricate these various species (Hagman, Hagrman & Zubieta, 1999). The pyridinecarboxylate ligand is also an attractive choice for its multifunctional linking groups (Evans & Lin, 2002). Furthermore, the polynuclear cadmium complexes are of interest not only for their novel structures but also for their photoluminescence properties (Tong et al., 1999). There are several polymers built from the nicotinate group and CdII centers, and these reported coordination polymers exhibit different types of topology, viz. discrete structure in tetraaquabis(nicotinate-N)cadmium(II) (Zhou el al., 2003), two-dimensional structure in catena-[bis(µ2-nicotinato-N,O,O')-aqua- cadmium(II)] (Clegg et al., 1995) and catena-[tetrakis(µ2-nicotinato-N,O,O') -bis(µ2-nicotinato-N,O)tetraaquatricadmium(II)] (Chen, 2003), and three-dimensional structure in catena-[(µ3-nicotinato)(µ2-nicotinato)cadmium(II)] (Evans & Lin 2001; Lu & Kohler 2002). In this paper, we report the first example of a one-dimensional coordination polymer, [Cd(C6H4O2N)2(H2O)2]n, (I).

The structure of (I) consists of a one-dimensional zigzag chain. The seven-coordinate Cd atoms exhibit a distorted pentagonal bipyramidal geometry, involving one N-donor and four O-donors of the two nicotinate ligands (one symmetry-related) lying almost in the equatorial plane, and two coordinated water molecules at the apex sites, as shown in Figs. 1 and 2; the r.m.s. deviation of the Cd from the mean plane is 0.124 (2) Å. The bond angles around the Cd1 atom range from 51.26 (14) to 174.42 (18)°. The Cd1—O distances range from 2.255 (4) to 2.724 (5) Å, while the Cd1—N distance is 2.278 (4) Å; all are in agreement with those reported in other Cd–nicotinate complexes, e.g. [Cd(C6H4NO2)2(H2O)] (Clegg et al., 1995). Both carboxylate groups are bound asymmetrically, with one Cd—O bond considerably longer than the other. There are two crystallographically independent nicotinate ligands, having two different coordination modes in (I) (Fig. 2). One acts as a tridentate ligand towards one Cd atom through its carboxylate group while simultaneously binding to a second symmetry-related Cd atom through the pyridine N atom. The other acts as a simple bidentate ligand through its carboxylate group. The dihedral angles between the carboxylate group and the main ring plane are 10.48 (2)° in the tridentate ligand and 2.97 (2)° in the bidentate ligand, so the tridentate ligand is markedly less planar than the bidentate ligand. This is presumably a consequence of the bridging nature of the ligands, with effective coordination to the metals being of primary importance.

A number of hydrated metal nicotinate structures have been reported. Only some dinuclear lanthanide complexes (with La, Pr, Sm, Ho or Tm) have both chelating and bridging nicotinate ligands (Moore, Glick & Baker, 1972; Prout, Marín & Hutchinson, 1985), but the N atoms of the ligand were not involved in binding to the metals. To our knowledge, complex (I) constitutes the first example of two such coordination modes in one crystal.

Each bridging nicotinate ligands connects two CdII ions into a one-dimensional structure in a head-to-tail manner. The chain propagates along the a axis, but adjacent chains are antiparellel, and hence there is a center of symmetry in the structure. As shown in Table 2, all H atoms of the bound water molecules engage in hydrogen bonds to the carboxylate O or uncoordinated N atoms of the pyridine rings in adjacent asymmetric units. The O···O distances range from 2.831 (6) to 3.082 (8) Å, and the O···N distance is 2.822 (8) Å. An extensive network of intermolecular hydrogen bonds link the one-dimensional chains to complete a three-dimensional framework.

Experimental top

Cd(CH3COO)2 (0.23 g, 1.0 mmol), m-pyridinecarboxylic acid (0.124 g, 1.0 mmol) and Na2B4O7.10H2O (0.19 g, 0.5 mmol) in a molar ratio of 2:2:1 and water (10 ml) were placed in a Parr Teflon-lined stainless steel vessel (25 ml). The vessel was sealed, heated to 433 K and maintained at that temperature for 3 d. The reactant was cooled at a rate of 0.5 K min−1, leading to the formation of colourless crystals of (I) (yield 63% based on Cd).

Refinement top

C-bound H atoms were positioned geometrically and refined using a riding model [C—H = 0.93 Å and Uiso(H) = 1.2Ueq(C)]. The aqua H atoms were located from difference maps and refined isotropically [Uiso(H) = 1.5Ueq(O)]. In the final diffence map, the deepest hole is 0.94 Å from atom Cd1 and the highest peak is 1.03 Å from atom C10.

Computing details top

Data collection: SMART (Siemens, 1996); cell refinement: SMART and SAINT (Siemens,1994); data reduction: SAINT and XPREP in SHELXTL (Siemens, 1994); program(s) used to solve structure: SHELXTL; program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.

Figures top
[Figure 1] Fig. 1. A view of (I), with 30% probability displacement ellipsoids. H atoms are shown as small spheres of arbitrary radii. [Symmetry code: (A) x − 1, y, z.]
[Figure 2] Fig. 2. The one-dimensional chain structure of (I), showing the two different coordination modes of the nicotinate ligand. H atoms and water molecules have been omited for clarity. [Symmetry code: (a) x − 1, y, z; (b) x + 1, y, z; (c) x + 2, y, z.]
catena-Poly[[diaqua(nicotinato-κ2O,O')cadmium(II)]-µ-nicotinato-κ3N:O,O'] top
Crystal data top
[Cd(C6H4O2N)2(H2O)2]F(000) = 776
Mr = 392.64Dx = 1.889 Mg m3
Monoclinic, P21/nMo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ynCell parameters from 2215 reflections
a = 7.8620 (3) Åθ = 2.2–25.1°
b = 12.6448 (5) ŵ = 1.61 mm1
c = 14.0134 (2) ÅT = 293 K
β = 97.755 (2)°Prism, colorless
V = 1380.38 (8) Å30.60 × 0.22 × 0.20 mm
Z = 4
Data collection top
Siemens SMART CCD area-detector
diffractometer
2438 independent reflections
Radiation source: fine-focus sealed tube1825 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.024
ϕ and ω scansθmax = 25.1°, θmin = 2.2°
Absorption correction: empirical (using intensity measurements)
(SADABS; Sheldrick, 1996)
h = 99
Tmin = 0.796, Tmax = 1.000k = 1315
4182 measured reflectionsl = 1216
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.039Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.118H atoms treated by a mixture of independent and constrained refinement
S = 1.04 w = 1/[σ2(Fo2) + (0.0595P)2 + 3.9106P]
where P = (Fo2 + 2Fc2)/3
2438 reflections(Δ/σ)max = 0.006
202 parametersΔρmax = 0.84 e Å3
4 restraintsΔρmin = 1.17 e Å3
Crystal data top
[Cd(C6H4O2N)2(H2O)2]V = 1380.38 (8) Å3
Mr = 392.64Z = 4
Monoclinic, P21/nMo Kα radiation
a = 7.8620 (3) ŵ = 1.61 mm1
b = 12.6448 (5) ÅT = 293 K
c = 14.0134 (2) Å0.60 × 0.22 × 0.20 mm
β = 97.755 (2)°
Data collection top
Siemens SMART CCD area-detector
diffractometer
2438 independent reflections
Absorption correction: empirical (using intensity measurements)
(SADABS; Sheldrick, 1996)
1825 reflections with I > 2σ(I)
Tmin = 0.796, Tmax = 1.000Rint = 0.024
4182 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0394 restraints
wR(F2) = 0.118H atoms treated by a mixture of independent and constrained refinement
S = 1.04Δρmax = 0.84 e Å3
2438 reflectionsΔρmin = 1.17 e Å3
202 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
xyzUiso*/Ueq
Cd10.24266 (4)0.00029 (3)1.15547 (3)0.03242 (17)
O1W0.1949 (7)0.0978 (4)1.3007 (4)0.0611 (13)
H1WB0.275 (8)0.073 (7)1.325 (6)0.092*
H1WA0.152 (11)0.157 (3)1.298 (6)0.092*
O10.4714 (5)0.0205 (3)1.1528 (3)0.0467 (11)
O2W0.2717 (6)0.0845 (4)1.0061 (3)0.0528 (11)
H2WA0.184 (6)0.102 (6)0.984 (6)0.079*
H2WB0.359 (6)0.055 (6)0.981 (5)0.079*
O20.5828 (5)0.1696 (4)1.2124 (4)0.0717 (15)
O30.3052 (6)0.1592 (3)1.0797 (3)0.0576 (12)
O40.0346 (6)0.1180 (3)1.0758 (3)0.0499 (11)
N10.0108 (5)0.1011 (3)1.2121 (3)0.0323 (10)
N20.0337 (9)0.3869 (5)0.9132 (4)0.0660 (17)
C10.1438 (7)0.0808 (4)1.1879 (4)0.0318 (12)
H10.15640.02171.15000.038*
C20.2863 (6)0.1424 (4)1.2157 (4)0.0337 (12)
C30.2659 (7)0.2300 (5)1.2714 (5)0.0486 (16)
H30.35840.27471.29060.058*
C40.1081 (8)0.2505 (5)1.2981 (5)0.0580 (19)
H40.09260.30861.33670.070*
C50.0263 (7)0.1853 (5)1.2680 (4)0.0433 (14)
H50.13290.19981.28700.052*
C60.4587 (7)0.1101 (5)1.1908 (4)0.0396 (14)
C70.0092 (9)0.3008 (5)0.9647 (5)0.0508 (16)
H70.10030.25370.97810.061*
C80.1414 (8)0.2775 (5)0.9991 (4)0.0432 (14)
C90.2795 (10)0.3460 (6)0.9785 (5)0.0608 (19)
H90.38450.33220.99980.073*
C100.2559 (11)0.4362 (6)0.9249 (6)0.073 (2)
H100.34500.48420.90900.087*
C110.0980 (13)0.4523 (7)0.8960 (6)0.078 (2)
H110.08230.51390.86190.093*
C120.1608 (8)0.1785 (5)1.0551 (4)0.0400 (13)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Cd10.0208 (2)0.0360 (3)0.0406 (3)0.00258 (17)0.00469 (16)0.00322 (18)
O1W0.057 (3)0.065 (3)0.062 (3)0.002 (3)0.010 (2)0.016 (3)
O10.030 (2)0.045 (3)0.067 (3)0.0057 (18)0.014 (2)0.000 (2)
O2W0.056 (3)0.054 (3)0.048 (3)0.019 (2)0.002 (2)0.006 (2)
O20.028 (2)0.102 (4)0.086 (4)0.013 (3)0.009 (2)0.036 (3)
O30.062 (3)0.043 (3)0.072 (3)0.008 (2)0.028 (2)0.010 (2)
O40.048 (3)0.042 (2)0.058 (3)0.006 (2)0.001 (2)0.012 (2)
N10.026 (2)0.034 (3)0.037 (2)0.0012 (19)0.0057 (19)0.003 (2)
N20.094 (5)0.052 (4)0.056 (4)0.001 (4)0.029 (3)0.013 (3)
C10.029 (3)0.034 (3)0.031 (3)0.002 (2)0.001 (2)0.004 (2)
C20.021 (3)0.040 (3)0.039 (3)0.001 (2)0.000 (2)0.002 (2)
C30.035 (3)0.046 (4)0.062 (4)0.006 (3)0.001 (3)0.016 (3)
C40.037 (3)0.056 (4)0.079 (5)0.005 (3)0.002 (3)0.040 (4)
C50.028 (3)0.045 (3)0.056 (4)0.003 (3)0.002 (3)0.022 (3)
C60.020 (3)0.060 (4)0.038 (3)0.002 (3)0.002 (2)0.002 (3)
C70.067 (5)0.042 (4)0.045 (3)0.005 (3)0.011 (3)0.005 (3)
C80.056 (4)0.038 (3)0.035 (3)0.004 (3)0.005 (3)0.002 (2)
C90.070 (5)0.057 (4)0.056 (4)0.020 (4)0.011 (4)0.008 (3)
C100.085 (6)0.067 (5)0.066 (5)0.030 (5)0.008 (4)0.021 (4)
C110.115 (8)0.056 (5)0.067 (5)0.014 (5)0.029 (5)0.026 (4)
C120.051 (4)0.033 (3)0.036 (3)0.003 (3)0.005 (3)0.003 (2)
Geometric parameters (Å, º) top
Cd1—O1i2.255 (4)N2—C71.335 (8)
Cd1—N12.278 (4)C1—C21.375 (7)
Cd1—O32.295 (4)C1—H10.9300
Cd1—O2W2.335 (5)C2—C31.377 (8)
Cd1—O1W2.366 (5)C2—C61.498 (7)
Cd1—O42.573 (4)C3—C41.366 (8)
Cd1—O2i2.724 (5)C3—H30.9300
O1W—H1WB0.82 (7)C4—C51.360 (8)
O1W—H1WA0.82 (5)C4—H40.9300
O1—C61.261 (7)C5—H50.9300
O1—Cd1ii2.255 (4)C7—C81.367 (9)
O2W—H2WA0.82 (5)C7—H70.9300
O2W—H2WB0.82 (6)C8—C91.387 (9)
O2—C61.236 (7)C8—C121.496 (8)
O3—C121.252 (7)C9—C101.391 (10)
O4—C121.254 (7)C9—H90.9300
N1—C11.328 (7)C10—C111.370 (11)
N1—C51.337 (7)C10—H100.9300
N2—C111.320 (10)C11—H110.9300
O1i—Cd1—N1133.32 (15)N1—C1—H1118.2
O1i—Cd1—O386.82 (16)C2—C1—H1118.2
N1—Cd1—O3139.86 (16)C1—C2—C3117.7 (5)
O1i—Cd1—O2W87.44 (17)C1—C2—C6120.3 (5)
N1—Cd1—O2W91.75 (15)C3—C2—C6121.9 (5)
O3—Cd1—O2W89.91 (16)C4—C3—C2119.1 (5)
O1i—Cd1—O1W96.71 (17)C4—C3—H3120.4
N1—Cd1—O1W88.13 (17)C2—C3—H3120.4
O3—Cd1—O1W86.61 (18)C5—C4—C3119.6 (6)
O2W—Cd1—O1W174.42 (18)C5—C4—H4120.2
O1i—Cd1—O4138.48 (15)C3—C4—H4120.2
N1—Cd1—O487.31 (14)N1—C5—C4122.5 (5)
O3—Cd1—O453.20 (15)N1—C5—H5118.8
O2W—Cd1—O482.38 (17)C4—C5—H5118.8
O1W—Cd1—O492.04 (16)O2—C6—O1123.1 (5)
O1i—Cd1—O2i51.26 (14)O2—C6—C2119.0 (6)
N1—Cd1—O2i82.17 (14)O1—C6—C2117.9 (5)
O3—Cd1—O2i137.86 (15)N2—C7—C8124.1 (6)
O2W—Cd1—O2i84.74 (18)N2—C7—H7117.9
O1W—Cd1—O2i100.76 (18)C8—C7—H7117.9
O4—Cd1—O2i163.09 (15)C7—C8—C9118.7 (6)
Cd1—O1W—H1WB97 (7)C7—C8—C12121.3 (5)
Cd1—O1W—H1WA117 (6)C9—C8—C12120.0 (6)
H1WB—O1W—H1WA135 (9)C8—C9—C10117.8 (7)
C6—O1—Cd1ii103.5 (4)C8—C9—H9121.1
Cd1—O2W—H2WA118 (6)C10—C9—H9121.1
Cd1—O2W—H2WB99 (6)C11—C10—C9118.2 (7)
H2WA—O2W—H2WB131 (8)C11—C10—H10120.9
C12—O3—Cd198.8 (4)C9—C10—H10120.9
C12—O4—Cd185.7 (3)N2—C11—C10124.8 (7)
C1—N1—C5117.5 (5)N2—C11—H11117.6
C1—N1—Cd1121.1 (3)C10—C11—H11117.6
C5—N1—Cd1121.4 (4)O3—C12—O4122.2 (5)
C11—N2—C7116.3 (7)O3—C12—C8117.9 (6)
N1—C1—C2123.7 (5)O4—C12—C8119.9 (5)
Symmetry codes: (i) x1, y, z; (ii) x+1, y, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2W—H2WA···O4iii0.82 (5)2.02 (6)2.831 (6)170 (8)
O1W—H1WB···N2iv0.82 (7)2.13 (6)2.822 (8)143 (9)
O1W—H1WA···O2v0.82 (5)2.27 (3)3.082 (8)170 (9)
O2W—H2WB···O1iii0.82 (6)2.18 (5)2.870 (6)142 (7)
Symmetry codes: (iii) x, y, z+2; (iv) x1/2, y+1/2, z+1/2; (v) x+1/2, y+1/2, z+5/2.

Experimental details

Crystal data
Chemical formula[Cd(C6H4O2N)2(H2O)2]
Mr392.64
Crystal system, space groupMonoclinic, P21/n
Temperature (K)293
a, b, c (Å)7.8620 (3), 12.6448 (5), 14.0134 (2)
β (°) 97.755 (2)
V3)1380.38 (8)
Z4
Radiation typeMo Kα
µ (mm1)1.61
Crystal size (mm)0.60 × 0.22 × 0.20
Data collection
DiffractometerSiemens SMART CCD area-detector
diffractometer
Absorption correctionEmpirical (using intensity measurements)
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.796, 1.000
No. of measured, independent and
observed [I > 2σ(I)] reflections
4182, 2438, 1825
Rint0.024
(sin θ/λ)max1)0.598
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.039, 0.118, 1.04
No. of reflections2438
No. of parameters202
No. of restraints4
H-atom treatmentH atoms treated by a mixture of independent and constrained refinement
Δρmax, Δρmin (e Å3)0.84, 1.17

Computer programs: SMART (Siemens, 1996), SMART and SAINT (Siemens,1994), SAINT and XPREP in SHELXTL (Siemens, 1994), SHELXTL.

Selected geometric parameters (Å, º) top
Cd1—O1i2.255 (4)Cd1—O1W2.366 (5)
Cd1—N12.278 (4)Cd1—O42.573 (4)
Cd1—O32.295 (4)Cd1—O2i2.724 (5)
Cd1—O2W2.335 (5)
N1—Cd1—O3139.86 (16)O2W—Cd1—O1W174.42 (18)
N1—Cd1—O2W91.75 (15)N1—Cd1—O487.31 (14)
O3—Cd1—O2W89.91 (16)O3—Cd1—O453.20 (15)
N1—Cd1—O1W88.13 (17)O2W—Cd1—O482.38 (17)
O3—Cd1—O1W86.61 (18)O1W—Cd1—O492.04 (16)
Symmetry code: (i) x1, y, z.
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
O2W—H2WA···O4ii0.82 (5)2.02 (6)2.831 (6)170 (8)
O1W—H1WB···N2iii0.82 (7)2.13 (6)2.822 (8)143 (9)
O1W—H1WA···O2iv0.82 (5)2.27 (3)3.082 (8)170 (9)
O2W—H2WB···O1ii0.82 (6)2.18 (5)2.870 (6)142 (7)
Symmetry codes: (ii) x, y, z+2; (iii) x1/2, y+1/2, z+1/2; (iv) x+1/2, y+1/2, z+5/2.
 

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