Poly[(μ₆-6-oxidopyridinium-2-carboxyl­ato)caesium]

The asymmetric unit of the polymeric title salt, [Cs(C₆H₄NO₃)]_n, comprises a Cs⁺ cation and a 6-oxidopyridinium-2-carboxyl­ate anion. The Cs⁺ cation is six-coordinated by O atoms derived from two oxido and four carboxyl­ate O atoms; each O atom in the anion bridges two Cs⁺ cations. In the crystal, inter­molecular N—H...O hydrogen bonding is present and contributes to the stability of the three-dimensional network generated by the bridging O atoms.

Key indicators

• Single-crystal X-ray study
• T = 296 K
• Mean [sigma](C-C) = 0.005 Å
• R factor = 0.028
• wR factor = 0.072
• Data-to-parameter ratio = 17.5

checkCIF/PLATON results

No syntax errors found



Alert level C
PLAT029_ALERT_3_C _diffrn_measured_fraction_theta_full Low .......      0.960
PLAT250_ALERT_2_C Large U3/U1 Ratio for Average U(i,j) Tensor ....        2.3
PLAT369_ALERT_2_C Long   C(sp2)-C(sp2) Bond  C3     -   C8     ...       1.53 Ang.
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600         26
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600         36

Alert level G
PLAT004_ALERT_5_G Info: Polymeric Structure Found with Dimension .          1
PLAT005_ALERT_5_G No _iucr_refine_instructions_details in CIF ....          ?
PLAT764_ALERT_4_G Overcomplete CIF Bond List Detected (Rep/Expd) .       1.31 Ratio

   0 ALERT level A = Most likely a serious problem - resolve or explain
   0 ALERT level B = A potentially serious problem, consider carefully
   5 ALERT level C = Check. Ensure it is not caused by an omission or oversight
   3 ALERT level G = General information/check it is not something unexpected

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

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S1. Comment

During studies of lanthanide complexes of picolinic acid and their derivatives due to their interesting photoluminescent properties (Kang, 2011; Lee & Kang, 2010; Hong et al., 2008), the title compound was obtained as a side-product.

The asymmetric unit of the title compound, [Cs(C₆H₄NO₃)]_n, comprises a Cs⁺ cation and a carboxylatooxidopyridinium anion. The Cs⁺ cation is coordinated to the two oxide O atoms and four carboxylate-O atoms (Fig. 1). The Cs—O bond distances lie within the range 2.938 (2) - 3.317 (2) Å (Table 1). The observed Cs—O distances are a little longer than those observed in caesium picrate complexes and caesium phenoxide complexes (Ungaro et al., 1994: Clark et al., 1998; Weinert et al., 2003). The dihedral angle between the pyridine ring and the carboxylate group is 6.95 (19) °. In the crystal structure, the Cs atoms are linked by O atoms of the anionic ligands to form a three-dimensional network (Fig. 2) with additional stability provided by intermolecular N—H···O hydrogen bonding (Table 2).

Related literature

For general background to pyridine carboxylic complexes, see: Kang (2011); Lee & Kang (2010); Hong et al. (2008). For the Cs—O bond distances in caesium aryloxide complexes, see: Ungaro et al. (1994); Clark et al. (1998); Weinert et al. (2003).

S2. Experimental

Europium trichloride solution was prepared by dissolving EuCl₃ 6H₂O (0.37 g, 1.0 mmol; Aldrich) in absolute ethanol (20 ml) at room temperature with stirring. The ligand solution was prepared by dissolving 6-hydroxypicolinic acid (0.56 g, 4.0 mmol; Aldrich) in absolute ethanol (30 ml) at room temperature. The pH of the ligand solution was adjusted to about 6 with 2 N CsOH solution. The Eu solution was added drop wise and slowly to the ligand solution. The reaction mixture was stirred for 2 h at room temperature. Colourless crystals of (I) were obtained at room temperature over a period of a few weeks. The complex was recrystallized from distilled water.

S3. Refinement

The N—H atom was located in a difference Fourier map and refined freely. The remaining H atoms were positioned geometrically and refined using a riding model with C—H = 0.93 Å, and with U_iso(H) = 1.2U_eq (C). The maximum and minimum residual electron density peaks of 1.19 and -1.14 e Å^-3, respectively, were located 0.83 Å and 0.71 Å from the Cs1 atom, respectively.

Computing details

Data collection: SMART (Bruker, 2002); cell refinement: SAINT (Bruker, 2002); data reduction: SAINT (Bruker, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and DIAMOND (Brandenburg, 2010)'; software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. Molecular structure of (l), showing the atom-numbering scheme and 20% probability ellipsoids. [Symmetry code: (i) -x + 1, y + 1/2, -z + 1/2; (ii) -x + 1, y - 1/2, -z + 1/2; (iii) x, -y + 1/2, z - 1/2; (iv) x + 1, -y + 1/2, z - 1/2; (v) -x, y - 1/2, -z + 1/2].
	Fig. 2. The three-dimensional framework of (I).

Poly[(µ₆-6-oxidopyridinium-2-carboxylato)caesium]

Crystal data

[Cs(C6H4NO3)]	F(000) = 504
Mr = 271.01	Dx = 2.356 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 3429 reflections
a = 8.1746 (3) Å	θ = 2.5–28.3°
b = 7.5513 (2) Å	µ = 4.8 mm^−1
c = 12.3843 (4) Å	T = 296 K
β = 91.889 (1)°	Block, colourless
V = 764.05 (4) Å^3	0.1 × 0.07 × 0.06 mm
Z = 4

Data collection

Bruker SMART CCD area-detector diffractometer	1592 reflections with I > 2σ(I)
ϕ and ω scans	Rint = 0.072
Absorption correction: multi-scan (SADABS; Bruker, 2002)	θmax = 28.3°, θmin = 2.5°
Tmin = 0.654, Tmax = 0.745	h = −3→10
6897 measured reflections	k = −10→7
1822 independent reflections	l = −15→15

Refinement

Refinement on F^2	0 restraints
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F^2 > 2σ(F^2)] = 0.028	w = 1/[σ^2(Fo^2) + (0.0401P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.072	(Δ/σ)max = 0.001
S = 1.00	Δρmax = 1.19 e Å^−3
1822 reflections	Δρmin = −1.14 e Å^−3
104 parameters

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Cs1	0.51201 (2)	0.14792 (3)	0.127051 (18)	0.04196 (11)
N2	0.0320 (3)	0.2743 (4)	0.4216 (2)	0.0304 (5)
H2	0.088 (4)	0.348 (4)	0.446 (3)	0.028 (9)*
C3	0.1062 (3)	0.1326 (4)	0.3746 (3)	0.0291 (6)
C4	0.0159 (4)	−0.0019 (5)	0.3335 (3)	0.0402 (8)
H4	0.0655	−0.0992	0.3023	0.048*
C5	−0.1567 (4)	0.0085 (5)	0.3391 (3)	0.0474 (9)
H5	−0.221	−0.0826	0.3102	0.057*
C6	−0.2296 (4)	0.1484 (5)	0.3857 (3)	0.0444 (9)
H6	−0.343	0.152	0.3888	0.053*
C7	−0.1347 (3)	0.2903 (5)	0.4302 (3)	0.0334 (7)
C8	0.2926 (3)	0.1403 (4)	0.3700 (3)	0.0298 (6)
O9	0.3603 (3)	0.0066 (3)	0.3335 (2)	0.0487 (6)
O10	0.3588 (2)	0.2803 (4)	0.3984 (2)	0.0536 (7)
O11	−0.1942 (2)	0.4235 (3)	0.4750 (2)	0.0498 (7)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cs1	0.03869 (13)	0.03507 (16)	0.05252 (19)	−0.00018 (7)	0.00759 (9)	−0.00010 (9)
N2	0.0203 (10)	0.0308 (14)	0.0402 (16)	−0.0019 (10)	0.0026 (9)	−0.0062 (12)
C3	0.0234 (12)	0.0316 (16)	0.0324 (17)	0.0012 (10)	0.0034 (10)	0.0006 (12)
C4	0.0313 (14)	0.0409 (19)	0.049 (2)	−0.0026 (12)	0.0044 (12)	−0.0145 (16)
C5	0.0316 (15)	0.049 (2)	0.061 (3)	−0.0137 (14)	−0.0003 (14)	−0.0201 (18)
C6	0.0216 (13)	0.056 (2)	0.055 (2)	−0.0055 (12)	0.0003 (13)	−0.0125 (17)
C7	0.0209 (11)	0.0393 (17)	0.0401 (19)	0.0013 (11)	0.0030 (10)	−0.0036 (15)
C8	0.0226 (12)	0.0325 (17)	0.0346 (18)	0.0020 (10)	0.0045 (10)	0.0017 (12)
O9	0.0321 (11)	0.0421 (14)	0.0725 (19)	0.0074 (10)	0.0112 (10)	−0.0090 (13)
O10	0.0235 (9)	0.0383 (14)	0.099 (2)	−0.0025 (9)	0.0070 (11)	−0.0189 (15)
O11	0.0244 (10)	0.0483 (15)	0.0772 (19)	0.0022 (10)	0.0070 (10)	−0.0231 (14)

Geometric parameters (Å, º)

Cs1—O9^i	2.938 (2)	C5—C6	1.352 (5)
Cs1—O10^ii	2.991 (3)	C5—H5	0.93
Cs1—O9	3.070 (3)	C6—C7	1.423 (4)
Cs1—O10^iii	3.105 (3)	C6—H6	0.93
Cs1—O11^iv	3.147 (2)	C7—O11	1.254 (4)
Cs1—O11^v	3.317 (2)	C8—O10	1.234 (4)
N2—C3	1.370 (4)	C8—O9	1.244 (4)
N2—C7	1.376 (3)	O9—Cs1^ii	2.938 (2)
N2—H2	0.78 (3)	O10—Cs1^i	2.991 (3)
C3—C4	1.345 (4)	O10—Cs1^vi	3.105 (3)
C3—C8	1.527 (4)	O11—Cs1^vii	3.147 (2)
C4—C5	1.418 (4)	O11—Cs1^viii	3.317 (2)
C4—H4	0.93
O9^i—Cs1—O10^ii	138.47 (6)	C3—N2—C7	123.8 (3)
O9^i—Cs1—O9	109.46 (5)	C3—N2—H2	118 (3)
O10^ii—Cs1—O9	85.35 (7)	C7—N2—H2	119 (3)
O9^i—Cs1—O10^iii	96.96 (7)	C4—C3—N2	120.3 (3)
O10^ii—Cs1—O10^iii	101.48 (6)	C4—C3—C8	123.4 (3)
O9—Cs1—O10^iii	131.16 (6)	N2—C3—C8	116.3 (2)
O9^i—Cs1—O11^iv	89.05 (7)	C3—C4—C5	118.3 (3)
O10^ii—Cs1—O11^iv	59.91 (6)	C3—C4—H4	120.8
O9—Cs1—O11^iv	140.90 (6)	C5—C4—H4	120.8
O10^iii—Cs1—O11^iv	77.13 (6)	C6—C5—C4	121.1 (3)
O9^i—Cs1—O11^v	143.52 (6)	C6—C5—H5	119.4
O10^ii—Cs1—O11^v	76.13 (6)	C4—C5—H5	119.4
O9—Cs1—O11^v	78.86 (6)	C5—C6—C7	120.8 (3)
O10^iii—Cs1—O11^v	56.95 (6)	C5—C6—H6	119.6
O11^iv—Cs1—O11^v	106.75 (4)	C7—C6—H6	119.6
O9^i—Cs1—O10	74.53 (6)	O11—C7—N2	120.3 (3)
O10^ii—Cs1—O10	118.05 (6)	O11—C7—C6	124.1 (3)
O9—Cs1—O10	36.14 (6)	N2—C7—C6	115.6 (3)
O10^iii—Cs1—O10	129.22 (5)	O10—C8—O9	127.1 (3)
O11^iv—Cs1—O10	149.72 (6)	O10—C8—C3	116.8 (3)
O11^v—Cs1—O10	101.34 (6)	O9—C8—C3	116.0 (3)
O9^i—Cs1—C7^iv	74.04 (7)	Cs1^ii—O9—Cs1	107.94 (7)
O10^ii—Cs1—C7^iv	76.81 (7)	Cs1^i—O10—Cs1^vi	78.52 (6)
O9—Cs1—C7^iv	153.81 (6)	Cs1^i—O10—Cs1	91.33 (7)
O10^iii—Cs1—C7^iv	72.02 (6)	Cs1^vi—O10—Cs1	136.48 (6)
O11^iv—Cs1—C7^iv	16.91 (7)	Cs1^vii—O11—Cs1^viii	73.25 (4)
O11^v—Cs1—C7^iv	114.40 (7)

Symmetry codes: (i) −x+1, y+1/2, −z+1/2; (ii) −x+1, y−1/2, −z+1/2; (iii) x, −y+1/2, z−1/2; (iv) x+1, −y+1/2, z−1/2; (v) −x, y−1/2, −z+1/2; (vi) x, −y+1/2, z+1/2; (vii) x−1, −y+1/2, z+1/2; (viii) −x, y+1/2, −z+1/2.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
N2—H2···O11^ix	0.78 (3)	2.15 (3)	2.915 (4)	168 (3)

Symmetry code: (ix) −x, −y+1, −z+1.