Poly[bis­(μ₂-4-pyridine­carboxyl­ato-κ³N:O,O′)cobalt(II)]: a triply inter­penetrated structure with diamonoid topology

The binary title complex, [Co(C₆H₄NO₂)₂]_n, is a three-dimensional coordination polymer that is triply inter­penetrated with diamonoid topology. The asymmetric unit comprises half a Co atom, which lies on a twofold axis, and a 4-pyridine­carboxyl­ate anion, in a general position. The Co atom is in a distorted cis-N₂O₄ octa­hedral geometry defined by two chelating carboxyl­ate groups and two pyridyl N atoms.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](C-C) = 0.003 Å
• R factor = 0.027
• wR factor = 0.063
• Data-to-parameter ratio = 14.8

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......       0.97
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         O1
PLAT241_ALERT_2_C Check High      Ueq as Compared to Neighbors for         O2
PLAT242_ALERT_2_C Check Low       Ueq as Compared to Neighbors for        Co1

Alert level G
REFLT03_ALERT_4_G Please check that the estimate of the number of Friedel pairs is
            correct. If it is not, please give the correct count in the
            _publ_section_exptl_refinement section of the submitted CIF.
           From the CIF: _diffrn_reflns_theta_max           27.50
           From the CIF: _reflns_number_total               1288
           Count of symmetry unique reflns          836
           Completeness (_total/calc)            154.07%
           TEST3: Check Friedels for noncentro structure
           Estimate of Friedel pairs measured       452
           Fraction of Friedel pairs measured     0.541
           Are heavy atom types Z>Si present        yes
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature .        293 K
PLAT794_ALERT_5_G Check Predicted Bond Valency for Co1         (3)       1.80

   0 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   4 ALERT level C = Check and explain
   4 ALERT level G = General alerts; check

   2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   3 ALERT type 2 Indicator that the structure model may be wrong or deficient
   1 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

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S1. Comment

Pyridinecarboxylates and their derivatives are good bridging ligands in the construction of 2- and 3-D functional metal-organic frameworks (Evans et al., 1999; Lu, 2003; Tong, Chen & Batten, 2003; Tong, Li et al., 2003; Wang et al., 2003). The title complex, (I), was obtained unexpectedly in an attempt to prepare a bimetallic coordination network (see Experimental) with 4-pyridinecarboxylate (4-pya).

The structure of (I) is a three-dimensional coordination network. The Co(II) atom, which is located on a 2-fold axis (Fig. 1), is coordinated by four O atoms derived from two chelating carboxylate ligands and two pyridine-N atoms that define a distorted octahedral geometry within a cis-N₂O₄ donor set. The major distortion from the ideal octahedral geometry is caused by the acute chelate angle of 60.43 (7)° for O1—Co—O2.

The Co—N bond length [2.0723 (16) Å] is slightly shorter than those of 2.133 (3) Å, found in [Co(4-pya)₂].0.5EtOH (Wei et al., 2004), and 2.166 (4) Å, found in [Co(4,4-bipyridine)(4-pya)(H₂O)]NO₃.4,4'-bipyridine.1.5H₂O (MacGillivray et al., 1998). By contrast, the Co—O bond distances of 2.1104 (16) and 2.2279 (16) Å are longer than those of 2.082 (4)–2.098 (4) Å formed by the 4-pya ligands in poly[tetrakis(µ₃-4-pya)dicobalt(II)] (Wei et al., 2004).

In the crystal structure, the polymeric chains are triply interpenetrated with a diamonoid topology (Fig. 2). This resembles the situation in [Zn(4-pya)₂]_n (Evans et al., 1999) but, the structures are not isomorphous.

Related literature

For related literature, see: Evans et al. (1999); Lu (2003); MacGillivray et al. (1998); Tong, Chen & Batten (2003); Tong, Li et al. (2003); Wang et al. (2003); Wei et al. (2004).

S2. Experimental

To a ethanol-water solution (2:1 v:v, 10 ml) of Co(NO₃)₂.6H₂O (0.146 g, 0.5 mmol) and Gd(NO₃)₃.6H₂O (0.226 g, 0.5 mmol), a solution of 4-pyridinecarboxylic acid (0.123 g, 1.0 mmol) in EtOH (5 ml) was added slowly with stirring over 30 min at 333 K. This solution was transferred into a sealed 23-ml Teflon-lined stainless container and heated to 160 °C for 3 days. After slow cooling to room temperature over 8 h, red crystals of (I) separated from the solution (yield 75%).

S3. Refinement

All the H atoms were included in the riding-model approximation, with C–H = 0.93 Å, and with U_iso(H) = 1.2U_eq(C).

Computing details

Data collection: SMART (Bruker, 1998); cell refinement: SAINT (Bruker, 1999); 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: ORTEPII (Johnson, 1976); software used to prepare material for publication: SHELXTL (Bruker, 1998).

Figures

	Fig. 1. Molecular structure of (I) extended to show the octahedral coordination geometry for the Co atom and the atom-labeling scheme. Displacement ellipsoids are shown at the 50% probability level. [Symmetry codes: (a) x - 1/2, -y + 1/2, -z - 3/4; (b) -y + 1/2, x - 1/2, z + 3/4; (c) y, x, -z; (d) y + 1/2, -x + 1/2, z - 3/4.]
	Fig. 2. Plot of a single diamonoid network in (I) viewed along the a axis.

Poly[bis(µ₂-4-pyridinecarboxylato-κ³N:O,O')cobalt(II)]

Crystal data

[Co(C6H4NO2)2]	Dx = 1.698 Mg m^−3
Mr = 303.13	Mo Kα radiation, λ = 0.71073 Å
Tetragonal, P43212	Cell parameters from 1288 reflections
Hall symbol: P 4nw 2abw	θ = 2.5–27.5°
a = 11.6304 (7) Å	µ = 1.46 mm^−1
c = 8.7665 (10) Å	T = 293 K
V = 1185.81 (17) Å^3	Block, red
Z = 4	0.21 × 0.15 × 0.07 mm
F(000) = 612

Data collection

Bruker SMART CCD area-detector diffractometer	1288 independent reflections
Radiation source: fine-focus sealed tube	1219 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.027
φ and ω scans	θmax = 27.5°, θmin = 2.5°
Absorption correction: multi-scan (SADABS; Sheldrick, 2002)	h = −10→14
Tmin = 0.749, Tmax = 0.905	k = −14→14
4769 measured reflections	l = −11→4

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.027	H-atom parameters constrained
wR(F^2) = 0.063	w = 1/[σ^2(Fo^2) + (0.033P)^2 + 0.0513P] where P = (Fo^2 + 2Fc^2)/3
S = 1.11	(Δ/σ)max < 0.001
1288 reflections	Δρmax = 0.39 e Å^−3
87 parameters	Δρmin = −0.24 e Å^−3
0 restraints	Absolute structure: (Flack, 1983)
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.03 (2)

Special details

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 (Ų)

	x	y	z	Uiso*/Ueq
Co1	0.27729 (2)	0.27729 (2)	0.0000	0.02511 (13)
O1	0.39522 (15)	0.18731 (17)	−0.13866 (18)	0.0475 (5)
O2	0.37226 (15)	0.37088 (16)	−0.18249 (19)	0.0457 (4)
N1	0.64350 (14)	0.24467 (16)	−0.59662 (19)	0.0299 (4)
C1	0.5913 (2)	0.15229 (19)	−0.5376 (2)	0.0369 (5)
H1	0.6066	0.0806	−0.5799	0.044*
C2	0.5157 (2)	0.1592 (2)	−0.4165 (3)	0.0370 (5)
H2	0.4812	0.0932	−0.3779	0.044*
C3	0.49211 (18)	0.2652 (2)	−0.3537 (2)	0.0315 (5)
C4	0.5420 (2)	0.36043 (19)	−0.4179 (3)	0.0354 (5)
H4	0.5257	0.4334	−0.3802	0.042*
C5	0.61669 (19)	0.34707 (18)	−0.5389 (2)	0.0331 (5)
H5	0.6497	0.4123	−0.5819	0.040*
C6	0.41504 (18)	0.2756 (2)	−0.2161 (2)	0.0352 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Co1	0.02932 (16)	0.02932 (16)	0.01668 (18)	−0.00108 (16)	0.00053 (11)	−0.00053 (11)
O1	0.0495 (10)	0.0624 (12)	0.0305 (8)	0.0157 (9)	0.0138 (8)	0.0114 (9)
O2	0.0435 (11)	0.0472 (11)	0.0464 (9)	−0.0054 (7)	0.0189 (8)	−0.0158 (9)
N1	0.0315 (9)	0.0357 (10)	0.0225 (8)	−0.0011 (7)	0.0037 (7)	0.0011 (7)
C1	0.0467 (14)	0.0288 (12)	0.0352 (12)	0.0008 (10)	0.0074 (11)	−0.0039 (10)
C2	0.0431 (13)	0.0349 (13)	0.0330 (11)	−0.0033 (11)	0.0104 (11)	0.0013 (10)
C3	0.0298 (11)	0.0408 (13)	0.0238 (9)	0.0012 (10)	0.0026 (9)	0.0011 (10)
C4	0.0412 (13)	0.0354 (13)	0.0294 (11)	0.0055 (10)	0.0035 (10)	−0.0063 (10)
C5	0.0414 (13)	0.0292 (11)	0.0288 (11)	−0.0013 (9)	0.0057 (9)	0.0034 (9)
C6	0.0291 (11)	0.0529 (14)	0.0235 (10)	−0.0028 (11)	0.0005 (8)	−0.0043 (11)

Geometric parameters (Å, º)

Co1—N1^i	2.0723 (16)	N1—Co1^iv	2.0723 (16)
Co1—N1^ii	2.0723 (16)	C1—C2	1.381 (3)
Co1—O1^iii	2.1104 (16)	C1—H1	0.9300
Co1—O1	2.1104 (16)	C2—C3	1.377 (3)
Co1—O2^iii	2.2279 (16)	C2—H2	0.9300
Co1—O2	2.2279 (16)	C3—C4	1.372 (3)
O1—C6	1.253 (3)	C3—C6	1.508 (3)
O2—C6	1.250 (3)	C4—C5	1.379 (3)
N1—C5	1.331 (3)	C4—H4	0.9300
N1—C1	1.338 (3)	C5—H5	0.9300
N1^i—Co1—N1^ii	103.65 (10)	C1—N1—Co1^iv	119.51 (15)
N1^i—Co1—O1^iii	94.67 (7)	N1—C1—C2	122.6 (2)
N1^ii—Co1—O1^iii	93.05 (7)	N1—C1—H1	118.7
N1^i—Co1—O1	93.05 (7)	C2—C1—H1	118.7
N1^ii—Co1—O1	94.67 (7)	C3—C2—C1	119.1 (2)
O1^iii—Co1—O1	167.50 (11)	C3—C2—H2	120.5
N1^i—Co1—O2^iii	153.36 (7)	C1—C2—H2	120.5
N1^ii—Co1—O2^iii	88.08 (6)	C4—C3—C2	118.33 (19)
O1^iii—Co1—O2^iii	60.43 (7)	C4—C3—C6	121.0 (2)
O1—Co1—O2^iii	109.99 (7)	C2—C3—C6	120.7 (2)
N1^i—Co1—O2	88.08 (6)	C3—C4—C5	119.4 (2)
N1^ii—Co1—O2	153.36 (7)	C3—C4—H4	120.3
O1^iii—Co1—O2	109.99 (7)	C5—C4—H4	120.3
O1—Co1—O2	60.43 (7)	N1—C5—C4	122.7 (2)
O2^iii—Co1—O2	91.79 (8)	N1—C5—H5	118.6
C6—O1—Co1	91.44 (14)	C4—C5—H5	118.6
C6—O2—Co1	86.20 (13)	O2—C6—O1	121.71 (19)
C5—N1—C1	117.73 (18)	O2—C6—C3	119.8 (2)
C5—N1—Co1^iv	122.20 (14)	O1—C6—C3	118.5 (2)

Symmetry codes: (i) x−1/2, −y+1/2, −z−3/4; (ii) −y+1/2, x−1/2, z+3/4; (iii) y, x, −z; (iv) y+1/2, −x+1/2, z−3/4.