Download citation
Download citation
link to html
The title complex, poly[bis­(μ6-pyridine-2,6-dicarboxyl­ato N-­oxide)nickel(II)disilver(I)], [Ag2Ni(C7H3NO5)2]n or [Ag2Ni(pydco)2]n (H2pydco = pyridine-2,6-dicarboxylic acid N-­oxide), has a two-dimensional sheet structure. The two carboxyl­ate groups adopt two coordination modes. The NiII ion displays a distorted octa­hedral geometry, bonded to two carboxyl­ate O atoms of two different pydco ligands and four O donors from another two ligands, i.e. two carboxyl­ate O atoms and two N-oxide O atoms. The AgI ion adopts a tetra­hedral coordination, linked by three O atoms of three different carboxyl­ate groups and an N-oxide O atom.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270107044794/dn3061sup1.cif
Contains datablocks I, global

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270107044794/dn3061Isup2.hkl
Contains datablock I

CCDC reference: 669149

Comment top

The design and synthesis of inorganic–organic composite coordination polymers exhibiting novel structures and properties have provided exciting new prospects (Cingolani et al., 2005; Dikarev et al., 2005). To date, a number of monometallic extended inorganic–organic composite materials have been synthesized by the combination of organic spacers and inorganic metal salts (Fujita et al., 1995). In contrast, mixed-metal organic–inorganic composite coordination polymers have not yet attracted great attention (Noro et al., 2005), although numerous bimetallic extended structures based on inorganic counterions such as cyanide have been reported (Larionova et al., 1999).

Pyridine-2,6-dicarboxylic acid N-oxide (H2pydco) has limited steric hindrance and weak stacking interactions and can offer the possibility of forming coordination polymers either through one of its carboxylate groups, which is a versatile coordination mode in other organic aromatic polycarboxylate ligands, or through its N-oxide bridge, which is a far better electron donor than the ring N atom of pyridine-2,6-dicarboxylic acid (Nathan et al., 1985; Lin et al., 2006; Wen et al., 2005). Although its parent, pyridine-2,6-dicarboxylic acid, has been thoroughly studied, the coordination chemistry of H2pydco has not been well explored hitherto. Therefore, much more work is required to extend our knowledge on the coordination behaviour of this ligand and its properties in forming coordination polymers. In contrast with the mixed metal–pydco system, to the best of our knowledge, no example of structural characterization has been reported. In this paper, we report the synthesis and crystal structure of the title compound, (I).

Compound (I) adopts a two-dimensional sheet structure with a one-dimensional helical chain. The NiII ion has a distorted octahedral geometry composed of two O atoms from carboxylate groups of two different pydco ligands and four O donors from another two pydco ligands, i.e. two carboxylate O atoms and two N-oxide O atoms. The AgI ion adopts a tetrahedral coordination, linked to three O atoms of three different carboxylate groups and N-oxide O atom (Fig. 1). The Ni—O bond lengths range from 1.917 (4) to 1.967 (4) Å, and the O—Ni—O bond angles range from 89.88 (8) to 180.0°.

The AgI centre adopts an AgO4 coordination environment, which consists of three carboxylate O donors from three different ligands and one O donor from an N-oxide group of another pydco ligand (Fig. 2). All the Ag—O bond lengths are in good agreement with reported values (Dong et al., 2004), and the O—Ag—O bond angles range from 82.22 (7) to 135.0 (2)°.

The N-oxide groups exhibit a bridging coordination mode [Not shown in scheme], while the carboxylate groups, as expected, are coordinated to the AgI ions in an unprecedented bridging bidentate? coordination mode, different from the monodentate mode observed in previous reports (Li et al., 2005). Thus, within the pydco ligand, the O atoms of the carboxylate groups exhibit two modes. One carboxylate group bridges one NiII ion and one AgI ion in a monodentate fashion involving only atom O4, while the other group adopts a bidentate mode via both O2 and O3, so each ligand links four AgI ions and two NiII ions. This results in a 16-membered metal–organic ring which is composed of two pydco ligands and two AgI ions, with one six-coordinated NiII ion located in the centre of the ring. These rings are linked through the pyridylcarboxylate groups to form one-dimensional zigzag chains (Fig. 2). Furthermore, the bridging O atoms of pydco extend adjacent chains by coordinating to the AgI and NiII atoms of the cyclic unit to generate a two-dimensional network (Fig. 2).

It noteworthy that, in this two-dimensional coordination polymer, there is one short ligand-supported Ag···Ag contact, Ag1···Ag1ii = 3.288 Å [3.2859 (14) Å in CIF data tables - please clarify] [symmetry code: (ii) 2 − x, 1 − y, 2 − z Please check added symmetry code], which is less than the van der Waals diameter of Ag (3.44 Å; Reference?).

In conclusion, this two-dimensional sheet structure with helical chains can be described as a new type of mixed-metal coordination polymer with the pydco ligand in which the framework is composed of tetrahedrally coordinated AgI and octahedrally coordinated NiII with the pydco ligand.

Experimental top

A solution of Na2(pydco) (21.8 mg, 0.01 mmol) in CH3CH2OH (15 ml) was layered upon an aqueous solution of NiCl2·2H2O (16 mg, 0.016 mmol) and AgAc (10 mg, 0.025 mmol). The resultant mixtures [Previous sentence implies no mixing - please clarify] were kept at room temperature for three weeks and yielded pale-green [Green in CIF data tables] crystals of (I).

Refinement top

The H atoms were positioned geometrically and treated as riding on their parent atoms, with C—H distances of 0.93 Å, and with Uiso(H) = 1.2Ueq(C).

Computing details top

Data collection: SMART (Bruker, 1998); cell refinement: SMART (Bruker, 1998); data reduction: SAINT (Bruker, 1999); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Bruker, 1998); software used to prepare material for publication: SHELXTL (Bruker, 1998).

Figures top
[Figure 1] Fig. 1. The molecular arrangement of (I), showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms have been omitted for clarity. [Symmetry codes: (i) 1 − x, 1 − y, 1 − z; (ii) 2 − x, 1 − y, 2 − z.]
[Figure 2] Fig. 2. A partial packing view, showing the formation of the two=dimensionnal sheet. [Symmetry codes: (i) x − 1, y, z; (ii) 2 − x, 1 − y, 2 − z; (iii) 1 − x, 1 − y, 1 − z; (iv) 1 + x, y, z.]
poly[bis(µ5-pyridine-2,6-dicarboxylato N-oxide)nickel(II)disilver(I)] top
Crystal data top
[Ag2Ni(C7H3NO5)2]Z = 1
Mr = 636.66F(000) = 306
Triclinic, P1Dx = 2.717 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 4.9739 (9) ÅCell parameters from 1422 reflections
b = 8.8459 (15) Åθ = 3.1–25.5°
c = 9.1479 (16) ŵ = 3.76 mm1
α = 93.829 (2)°T = 298 K
β = 94.930 (2)°Block, green
γ = 103.061 (1)°0.25 × 0.21 × 0.18 mm
V = 389.09 (12) Å3
Data collection top
Bruker APEXII area-detector
diffractometer
1422 independent reflections
Radiation source: fine-focus sealed tube1346 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.012
ϕ and ω scansθmax = 25.5°, θmin = 3.1°
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
h = 56
Tmin = 0.454, Tmax = 0.551k = 1010
2890 measured reflectionsl = 1011
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)] = 0.045Hydrogen site location: inferred from neighbouring sites
wR(F2) = 0.097H-atom parameters constrained
S = 1.14 w = 1/[σ2(Fo2) + 5.6116P]
where P = (Fo2 + 2Fc2)/3
1422 reflections(Δ/σ)max < 0.001
133 parametersΔρmax = 3.04 e Å3
0 restraintsΔρmin = 2.51 e Å3
Crystal data top
[Ag2Ni(C7H3NO5)2]γ = 103.061 (1)°
Mr = 636.66V = 389.09 (12) Å3
Triclinic, P1Z = 1
a = 4.9739 (9) ÅMo Kα radiation
b = 8.8459 (15) ŵ = 3.76 mm1
c = 9.1479 (16) ÅT = 298 K
α = 93.829 (2)°0.25 × 0.21 × 0.18 mm
β = 94.930 (2)°
Data collection top
Bruker APEXII area-detector
diffractometer
1422 independent reflections
Absorption correction: multi-scan
(SADABS; Sheldrick, 1996)
1346 reflections with I > 2σ(I)
Tmin = 0.454, Tmax = 0.551Rint = 0.012
2890 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.0450 restraints
wR(F2) = 0.097H-atom parameters constrained
S = 1.14Δρmax = 3.04 e Å3
1422 reflectionsΔρmin = 2.51 e Å3
133 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
Ag11.07636 (14)0.45104 (8)0.83487 (7)0.0412 (2)
Ni10.50000.50000.50000.0149 (3)
O10.4596 (9)0.5871 (5)0.6920 (5)0.0201 (9)
O21.0107 (11)0.7018 (6)0.8727 (7)0.0393 (13)
O30.7031 (13)0.6999 (7)1.0355 (6)0.0443 (15)
O40.2281 (10)0.6074 (5)0.4127 (5)0.0237 (10)
O50.0988 (10)0.7355 (6)0.4547 (6)0.0321 (12)
N10.4793 (10)0.7438 (6)0.7063 (5)0.0160 (10)
C10.6450 (13)0.8259 (8)0.8221 (7)0.0200 (13)
C20.6588 (14)0.9841 (8)0.8478 (8)0.0249 (14)
H20.77591.04260.92630.030*
C30.4972 (15)1.0541 (8)0.7560 (8)0.0278 (15)
H30.50471.15990.77210.033*
C40.3244 (14)0.9649 (8)0.6400 (7)0.0239 (14)
H40.21421.01130.57850.029*
C50.3132 (13)0.8072 (7)0.6140 (7)0.0182 (13)
C60.8002 (14)0.7321 (8)0.9180 (7)0.0238 (14)
C70.1296 (14)0.7078 (8)0.4858 (7)0.0212 (14)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ag10.0478 (4)0.0416 (4)0.0427 (4)0.0201 (3)0.0127 (3)0.0205 (3)
Ni10.0175 (6)0.0173 (5)0.0120 (5)0.0109 (4)0.0024 (4)0.0024 (4)
O10.030 (2)0.013 (2)0.020 (2)0.0083 (18)0.0034 (19)0.0013 (17)
O20.026 (3)0.041 (3)0.057 (4)0.016 (2)0.010 (3)0.015 (3)
O30.068 (4)0.055 (4)0.025 (3)0.039 (3)0.014 (3)0.014 (3)
O40.026 (2)0.026 (2)0.021 (2)0.013 (2)0.0003 (19)0.0021 (19)
O50.023 (3)0.028 (3)0.046 (3)0.014 (2)0.012 (2)0.004 (2)
N10.017 (3)0.016 (2)0.016 (3)0.006 (2)0.002 (2)0.000 (2)
C10.019 (3)0.023 (3)0.019 (3)0.007 (3)0.004 (3)0.000 (3)
C20.025 (4)0.022 (3)0.025 (3)0.002 (3)0.001 (3)0.004 (3)
C30.037 (4)0.018 (3)0.031 (4)0.010 (3)0.008 (3)0.000 (3)
C40.026 (4)0.023 (3)0.026 (4)0.013 (3)0.002 (3)0.005 (3)
C50.020 (3)0.019 (3)0.017 (3)0.008 (3)0.001 (2)0.001 (2)
C60.026 (4)0.020 (3)0.024 (4)0.007 (3)0.004 (3)0.002 (3)
C70.023 (3)0.022 (3)0.021 (3)0.009 (3)0.001 (3)0.006 (3)
Geometric parameters (Å, º) top
Ag1—O3i2.246 (5)O4—C71.284 (8)
Ag1—O22.322 (5)O4—Ag1iii2.567 (5)
Ag1—O1ii2.528 (5)O5—C71.229 (8)
Ag1—O4iii2.567 (5)N1—C11.343 (8)
Ag1—Ag1i3.2859 (14)N1—C51.365 (8)
Ni1—O11.916 (4)C1—C21.389 (9)
Ni1—O1iii1.916 (4)C1—C61.525 (9)
Ni1—O41.966 (4)C2—C31.383 (10)
Ni1—O4iii1.966 (4)C2—H20.9300
O1—N11.364 (6)C3—C41.383 (10)
O1—Ag1iv2.528 (5)C3—H30.9300
O2—C61.236 (9)C4—C51.387 (9)
O3—C61.240 (9)C4—H40.9300
O3—Ag1i2.246 (5)C5—C71.516 (9)
O3i—Ag1—O2135.2 (2)C1—N1—O1116.9 (5)
O3i—Ag1—O1ii100.88 (19)C1—N1—C5123.1 (5)
O2—Ag1—O1ii82.17 (16)O1—N1—C5119.7 (5)
O3i—Ag1—O4iii130.96 (19)N1—C1—C2119.5 (6)
O2—Ag1—O4iii93.71 (18)N1—C1—C6115.3 (5)
O1ii—Ag1—O4iii86.27 (15)C2—C1—C6125.2 (6)
O3i—Ag1—Ag1i81.10 (14)C3—C2—C1119.6 (6)
O2—Ag1—Ag1i64.37 (15)C3—C2—H2120.2
O1ii—Ag1—Ag1i129.35 (10)C1—C2—H2120.2
O4iii—Ag1—Ag1i130.25 (11)C2—C3—C4119.3 (6)
O1—Ni1—O1iii180.000 (1)C2—C3—H3120.4
O1—Ni1—O490.03 (18)C4—C3—H3120.4
O1iii—Ni1—O489.97 (18)C3—C4—C5120.9 (6)
O1—Ni1—O4iii89.97 (18)C3—C4—H4119.5
O1iii—Ni1—O4iii90.03 (18)C5—C4—H4119.5
O4—Ni1—O4iii180.000 (1)N1—C5—C4117.7 (6)
N1—O1—Ni1115.9 (3)N1—C5—C7120.4 (5)
N1—O1—Ag1iv109.7 (3)C4—C5—C7121.9 (6)
Ni1—O1—Ag1iv119.9 (2)O2—C6—O3127.8 (7)
C6—O2—Ag1123.9 (5)O2—C6—C1116.9 (6)
C6—O3—Ag1i113.6 (5)O3—C6—C1115.3 (6)
C7—O4—Ni1123.6 (4)O5—C7—O4124.7 (6)
C7—O4—Ag1iii104.7 (4)O5—C7—C5117.0 (6)
Ni1—O4—Ag1iii130.6 (2)O4—C7—C5118.2 (5)
Symmetry codes: (i) x+2, y+1, z+2; (ii) x+1, y, z; (iii) x+1, y+1, z+1; (iv) x1, y, z.

Experimental details

Crystal data
Chemical formula[Ag2Ni(C7H3NO5)2]
Mr636.66
Crystal system, space groupTriclinic, P1
Temperature (K)298
a, b, c (Å)4.9739 (9), 8.8459 (15), 9.1479 (16)
α, β, γ (°)93.829 (2), 94.930 (2), 103.061 (1)
V3)389.09 (12)
Z1
Radiation typeMo Kα
µ (mm1)3.76
Crystal size (mm)0.25 × 0.21 × 0.18
Data collection
DiffractometerBruker APEXII area-detector
diffractometer
Absorption correctionMulti-scan
(SADABS; Sheldrick, 1996)
Tmin, Tmax0.454, 0.551
No. of measured, independent and
observed [I > 2σ(I)] reflections
2890, 1422, 1346
Rint0.012
(sin θ/λ)max1)0.606
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.045, 0.097, 1.14
No. of reflections1422
No. of parameters133
H-atom treatmentH-atom parameters constrained
Δρmax, Δρmin (e Å3)3.04, 2.51

Computer programs: SMART (Bruker, 1998), SAINT (Bruker, 1999), SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SHELXTL (Bruker, 1998).

 

Follow Acta Cryst. C
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds