Diaqua­bis(4-fluoro­benzoato-κO)bis(nicotinamide-κN)cobalt(II)

The title compound, [Co(C₇H₄FO₂)₂(C₆H₆N₂O)₂(H₂O)₂], is a three-dimensional hydrogen-bonded supra­molecular com­plex. The Co^II ion resides on a centre of symmetry and is in an octa­hedral coordination environment comprising two pyridyl N atoms, two carboxyl­ate O atoms and two O atoms from water mol­ecules. Inter­molecular N—H...O and O—H...O hydrogen bonds produce R₃²(6), R₂²(12) and R₂²(16) rings, which lead to two-dimensional chains. An extensive three-dimensional network of C—H...F, N—H...O and O—H...O hydrogen bonds and π–π inter­actions are responsible for crystal stabilization.

S1. Comment

Metal-organic supramolecular complexes with various fascinating topologies have been studied widely for their versatile chemical and physical properties and potential applications as functional materials (Janiak, 2003; Kitagawa et al., 2004; Yaghi et al., 2003). Self-assembly based on molecular building blocks has become an effective approach to construct these functional materials. In the development of supramolecular chemistry, hydrogen-bonding and π-π interactions acting as two main driving forces play an important role in self-assembling multi-dimensional metal-organic supramolecular frameworks or networks (Graham & Pike, 2000; Mitzi et al., 1995). Some interesting coordination polymers assembled with 4,4'-bipyridine (bipy) have been reported, showing various structural motifs, including two-dimensional layers (Carlucci et al., 1997; Tong et al., 1998) and three-dimensional nets (Lu et al., 1998; Hagrman, et al., 1998; Kondo, et al., 1999; Greve et al. 2003; Zhang et al., 1999). We report here the structure of the title compound, (I), in which hydrogen-bond interactions lead to a three-dimensional supramolecular network.

The molecular structure, with the atomic labelling scheme, is presented in Fig. 1. Compound (I) crystallizes in space group P2₁/n with Z' = 1/2. The Co^II ion is located on a symmetry center and is coordinated by two O atoms from two equivalent carboxylate groups and two O atoms from two water molecules, which form the equatorial plane, and by two N atoms from as many 4,4'-bpy ligands at the axial positions (Table 1). The coordination geometry around the Co^II ion can be described as a slightly distorted octahedron. The distortion arises from the N1—Co1—N1ⁱ axis, which is not perfectly perpendicular to the coordination plane (O2/O4/O2ⁱ/O4ⁱ/Co1). Carboxylate atom O3 is pendant, with a longer Co1···O3 distance [3.347 (2) Å] and larger Co1—O2—C7 angle consistent with the absence of bonding between Co1 and O3. The carboxylate group is not coplanar with the attached benzene ring, the dihedral angle between the planes being 8.7 (3)°. The pyridine and benzene rings are planar, the maximum deviation from the least-squares planes being 0.0042 (15) Å for atom C3 and 0.0056 (16) Å for atom C8.

Molecules are linked by intermolecular hydrogen bonding, and we employ graph-set notation (Bernstein et al., 1995) to describe the resulting patterns. Molecules of (I) are linked into sheets by a combination of O—H···O, N—H···O, C—H···O and C—H···F hydrogen bonds (Table 2). Thus, the C5—H5···O2, O4—H4A···O3 and C1—H1···O2ⁱ hydrogen bonds produce an S(5)S(6)S(5) motif (Fig. 1). Ring atom C5 in the reference molecule at (x, y, z) acts as hydrogen-bond donor, via H5, to atom F1^v, so forming a C(11)[R₂²(22)] chain of rings running parallel to the [100] direction and centrosymmetric R₂²(22) rings centred at (n + 1/2, 1/2, 1/2) (n = zero or integer) (Fig. 2). Fig. 3 shows the way in which the amino group, aqua ligand and carboxylate atom O1 enter into intermolecular hydrogen-bonding interactions. As a result, zigzag tapes are formed through O4—H4B···O1^iv, N2ⁱⁱⁱ—H2Bⁱⁱⁱ···O1^iv, N2ⁱⁱⁱ—H2Aⁱⁱⁱ···O4 and N2—H2B···O1ⁱⁱⁱ interactions [symmetry codes in Table 2], which define R₃²(6) and R₂²(12) ring patterns. Furthermore, water atom O4 in the reference molecule at (x, y, z) acts as hydrogen-bond donor, via H4B, to atom O1^iv, so forming a C(8)[R₂²(16)] chain of rings running parallel to the [010] direction and centrosymmetric R₂²(16) rings centred at (0, n, 1/2) (n = zero or integer). Propagation of three hydrogen bonds thus forms a complex chain of rings, containing R₃²(6)R₂²(12)R₂²(16) sequences of three edge-fused rings.

In the extended structure of (I), shown in Fig. 4, an intermolecular π–π contact occurs between the two symmetry-related pyridine rings of neighbouring molecules. Ring A is oriented in such a way that the perpendicular distance from A to A^vi is 3.588 Å [symmetry code: (vi) -x, -y + 2, -z + 1]. The distance between the ring centroids is 3.7612 (12) Å. The π–π interaction produces a chain running parallel to the [010] direction.

These intermolecular interactions, namely an extensive network of hydrogen bonds and π-π stacking, are responsible for constructing an infinite three-dimensional lattice in the crystal structure of (I).

Related literature

For related literature, see: Bernstein et al. (1995); Carlucci et al. (1997); Graham & Pike (2000); Greve et al. (2003); Hagrman et al. (1998); Janiak (2003); Kitagawa et al. (2004); Kondo et al. (1999); Lu et al. (1998); Mitzi et al. (1995); Tong et al. (1998); Yaghi et al. (2003); Zhang et al. (1999).

S2. Experimental

p-Halogenbenzoic acid sodium salts were prepared according to the following equation: 2 p-FBA + 2 NaHCO₃ → 2 Na(p-FBA) + 2 CO₂ + 2 H₂O (p-FBA is p-fluorobenzoic acid). The Co^II–p-FBA salt was then synthesized from the Na(p-FBA) salt by the substitution reaction 2 Na(p-FBA) + CoSO₄·6H₂O → Co(p-FBA)₂.nH₂O + Na₂SO₄. The compounds Co(p-FBA)₂.nH₂O were obtained in aqueous media. For the synthesis of the mixed-ligand complexes, a solution of dena (2 mmol) in distilled water (30 ml) was added dropwise with stirring to a solution of Co(p-FBA)₂.nH₂O (1 mmol) in hot distilled water (50 ml). The solutions were heated to 323 K in a temperature-controlled bath and stirred for 4 h, and then cooled to room temperature and allowed 10–12 days for crystallization. The crystals formed were filtered off, washed with cold water and acetone, and dried in vacuo. The mixed-ligand complexes were prepared according to the following equations: Co(p-FBA)₂.nH₂O + 2 N A → [Co(p-FBA)₂(NA)₂(H₂O)₂] (NA is nicotinamide). Analysis found: C 50.57, H 3.89, N 9.10; calculated for C₂₆H₂₄CoF₂N₄O₈: C 50.73, H 4.01, N 9.37%.

S3. Refinement

H atoms bonded to C and N atoms were included in their expected positions and allowed to ride, with C—H and N—H distances restrained to 0.93 and 0.86 Å, respectively; H atoms were assigned a U_iso(H) value of 1.2U_eq of the parent atom. Water H atoms were located in difference maps and refined subject to a DFIX restraint of O—H = 0.83 (2) Å.

Computing details

Data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-RED32 (Stoe & Cie, 2002); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: WinGX (Farrugia, 1999).

Figures

	Fig. 1. View of one molecule of (I), with the atom-numbering scheme. Hydrogen bonds are indicated by dashed lines. Displacement ellipsoids are drawn at the 30% probability level. [Symmety code: (i) -x, -y + 1, -z + 1.]
	Fig. 2. Part of the crystal structure of (I), showing the formation of a centrosymmetric R2^2(22) dimer. Dashed lines indicate hydrogen bonds. H atoms not involved in these interactions have been omitted for clarity.
	Fig. 3. Part of the crystal structure of (I), showing the formation of an edge-fused chain of R3^2(6), R2^2(12) and R2^2(16) rings. H atoms not involved in these interactions have been omitted for clarity. [Symmetry codes as in Table 2.]
	Fig. 4. Part of the crystal structure of (I), showing the formation of a chain along [010] generated by the π–π interaction. For the sake of clarity, H atoms have been omitted. [Symmetry code: (vi) -x, -y + 2, -z + 1.]

Diaquabis(4-fluorobenzoato-κO)bis(nicotinamide-κN)cobalt(II)

Crystal data

[Co(C7H4FO2)2(C6H6N2O)2(H2O)2]	F(000) = 634
Mr = 617.42	Dx = 1.545 Mg m^−3
Monoclinic, P21/n	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P2yn	Cell parameters from 6945 reflections
a = 11.9883 (10) Å	θ = 2.3–28.0°
b = 8.9128 (5) Å	µ = 0.72 mm^−1
c = 12.4236 (15) Å	T = 296 K
β = 90.499 (8)°	Prism, brown
V = 1327.4 (2) Å^3	0.62 × 0.48 × 0.41 mm
Z = 2

Data collection

Stoe IPDSII diffractometer	3148 independent reflections
Radiation source: fine-focus sealed tube	2717 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.077
Detector resolution: 6.67 pixels mm^-1	θmax = 28.0°, θmin = 2.4°
ω scans	h = −15→15
Absorption correction: integration (X-RED32; Stoe & Cie, 2002)	k = −11→11
Tmin = 0.707, Tmax = 0.795	l = −16→12
8334 measured reflections

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)] = 0.043	H atoms treated by a mixture of independent and constrained refinement
wR(F^2) = 0.121	w = 1/[σ^2(Fo^2) + (0.0713P)^2 + 0.2206P] where P = (Fo^2 + 2Fc^2)/3
S = 1.06	(Δ/σ)max < 0.001
3148 reflections	Δρmax = 0.34 e Å^−3
196 parameters	Δρmin = −0.68 e Å^−3
3 restraints	Extinction correction: SHELXL97, Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.039 (4)

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
C1	−0.06524 (14)	0.79487 (18)	0.38746 (15)	0.0336 (4)
H1	−0.1344	0.7477	0.3856	0.040*
C2	−0.05660 (15)	0.93826 (18)	0.34495 (14)	0.0329 (4)
C3	0.04687 (18)	1.00796 (19)	0.34791 (18)	0.0391 (4)
H3	0.0556	1.1044	0.3207	0.047*
C4	0.13648 (16)	0.9322 (2)	0.39171 (19)	0.0432 (4)
H4	0.2068	0.9763	0.3939	0.052*
C5	0.12037 (15)	0.7896 (2)	0.43239 (17)	0.0396 (4)
H5	0.1812	0.7391	0.4620	0.048*
C6	−0.15577 (17)	1.01884 (19)	0.29945 (17)	0.0363 (4)
C7	0.21193 (15)	0.3808 (2)	0.40259 (16)	0.0382 (4)
C8	0.32593 (15)	0.3168 (2)	0.42432 (16)	0.0393 (4)
C9	0.3837 (2)	0.3533 (3)	0.5179 (2)	0.0583 (6)
H9	0.3524	0.4193	0.5671	0.070*
C10	0.4882 (2)	0.2918 (4)	0.5385 (3)	0.0718 (8)
H10	0.5277	0.3161	0.6009	0.086*
C11	0.53095 (19)	0.1954 (3)	0.4651 (2)	0.0590 (6)
C12	0.4765 (2)	0.1551 (3)	0.3724 (2)	0.0565 (6)
H12	0.5084	0.0882	0.3242	0.068*
C13	0.37263 (18)	0.2167 (3)	0.35247 (18)	0.0468 (5)
H13	0.3337	0.1907	0.2901	0.056*
N1	0.02130 (12)	0.72127 (15)	0.43103 (13)	0.0340 (3)
N2	−0.23859 (17)	0.93759 (19)	0.26235 (19)	0.0570 (6)
H2A	−0.2965	0.9805	0.2350	0.068*
H2B	−0.2351	0.8413	0.2654	0.068*
O1	−0.15780 (12)	1.15703 (14)	0.29649 (13)	0.0466 (4)
O2	0.16709 (11)	0.45372 (16)	0.47834 (12)	0.0409 (3)
O3	0.16791 (13)	0.3555 (2)	0.31282 (13)	0.0577 (4)
O4	−0.03904 (11)	0.41631 (14)	0.34361 (12)	0.0389 (3)
H4A	0.0285 (15)	0.400 (3)	0.327 (3)	0.078 (10)*
H4B	−0.0732 (19)	0.333 (2)	0.339 (2)	0.056 (7)*
F1	0.63373 (13)	0.1361 (2)	0.48426 (19)	0.0912 (6)
Co1	0.0000	0.5000	0.5000	0.03135 (15)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
C1	0.0317 (8)	0.0258 (7)	0.0433 (9)	−0.0020 (6)	−0.0077 (7)	0.0032 (6)
C2	0.0360 (8)	0.0242 (7)	0.0385 (8)	0.0009 (6)	−0.0080 (7)	0.0007 (6)
C3	0.0401 (10)	0.0273 (8)	0.0497 (10)	−0.0049 (6)	−0.0088 (8)	0.0054 (7)
C4	0.0338 (9)	0.0344 (9)	0.0614 (12)	−0.0058 (7)	−0.0093 (8)	0.0056 (8)
C5	0.0334 (8)	0.0316 (8)	0.0537 (11)	0.0009 (7)	−0.0093 (8)	0.0032 (8)
C6	0.0388 (9)	0.0244 (7)	0.0454 (10)	0.0001 (6)	−0.0121 (8)	0.0019 (6)
C7	0.0321 (8)	0.0366 (9)	0.0458 (10)	−0.0018 (7)	−0.0022 (7)	0.0073 (7)
C8	0.0330 (8)	0.0386 (9)	0.0463 (10)	0.0006 (7)	−0.0007 (7)	0.0037 (8)
C9	0.0440 (11)	0.0717 (15)	0.0591 (13)	0.0122 (11)	−0.0104 (10)	−0.0192 (12)
C10	0.0451 (13)	0.099 (2)	0.0712 (16)	0.0121 (13)	−0.0187 (12)	−0.0181 (17)
C11	0.0353 (10)	0.0638 (14)	0.0779 (16)	0.0122 (10)	−0.0049 (10)	0.0025 (12)
C12	0.0462 (11)	0.0582 (13)	0.0651 (14)	0.0118 (10)	0.0079 (10)	−0.0051 (11)
C13	0.0405 (10)	0.0537 (11)	0.0460 (10)	0.0023 (9)	−0.0003 (8)	−0.0012 (9)
N1	0.0351 (7)	0.0243 (6)	0.0425 (8)	0.0000 (5)	−0.0093 (6)	0.0043 (6)
N2	0.0506 (10)	0.0266 (8)	0.0931 (15)	−0.0013 (7)	−0.0375 (10)	0.0040 (8)
O1	0.0489 (8)	0.0229 (6)	0.0675 (10)	0.0007 (5)	−0.0214 (7)	0.0033 (6)
O2	0.0316 (6)	0.0341 (6)	0.0570 (8)	0.0034 (5)	−0.0049 (6)	−0.0016 (6)
O3	0.0420 (8)	0.0830 (12)	0.0480 (8)	0.0064 (8)	−0.0079 (7)	0.0027 (8)
O4	0.0367 (7)	0.0310 (6)	0.0487 (7)	−0.0026 (5)	−0.0133 (6)	0.0016 (5)
F1	0.0428 (8)	0.1082 (15)	0.1225 (16)	0.0297 (9)	−0.0130 (9)	−0.0027 (12)
Co1	0.0286 (2)	0.0229 (2)	0.0424 (2)	0.00112 (10)	−0.00896 (13)	0.00335 (11)

Geometric parameters (Å, º)

C1—N1	1.338 (2)	C8—C9	1.386 (3)
C1—C2	1.387 (2)	C9—C10	1.389 (3)
C1—H1	0.9300	C9—H9	0.9300
C2—C3	1.388 (3)	C10—C11	1.357 (4)
C2—C6	1.496 (2)	C10—H10	0.9300
C3—C4	1.377 (3)	C11—F1	1.360 (3)
C3—H3	0.9300	C11—C12	1.368 (4)
C4—C5	1.382 (3)	C12—C13	1.381 (3)
C4—H4	0.9300	C12—H12	0.9300
C5—N1	1.335 (2)	C13—H13	0.9300
C5—H5	0.9300	N1—Co1	2.1662 (14)
C6—O1	1.232 (2)	N2—H2A	0.8600
C6—N2	1.309 (3)	N2—H2B	0.8600
C7—O3	1.250 (3)	O2—Co1	2.0650 (13)
C7—O2	1.267 (3)	O4—Co1	2.1294 (14)
C7—C8	1.503 (3)	O4—H4A	0.850 (17)
C8—C13	1.384 (3)	O4—H4B	0.848 (16)
N1—C1—C2	123.06 (16)	C11—C10—H10	120.9
N1—C1—H1	118.5	C9—C10—H10	120.9
C2—C1—H1	118.5	C10—C11—F1	118.4 (2)
C1—C2—C3	118.18 (15)	C10—C11—C12	123.5 (2)
C1—C2—C6	121.64 (15)	F1—C11—C12	118.1 (2)
C3—C2—C6	120.16 (15)	C11—C12—C13	118.0 (2)
C4—C3—C2	119.02 (16)	C11—C12—H12	121.0
C4—C3—H3	120.5	C13—C12—H12	121.0
C2—C3—H3	120.5	C12—C13—C8	120.7 (2)
C3—C4—C5	118.98 (17)	C12—C13—H13	119.7
C3—C4—H4	120.5	C8—C13—H13	119.7
C5—C4—H4	120.5	C5—N1—C1	117.91 (14)
N1—C5—C4	122.84 (16)	C5—N1—Co1	121.23 (11)
N1—C5—H5	118.6	C1—N1—Co1	120.85 (11)
C4—C5—H5	118.6	C6—N2—H2A	120.0
O1—C6—N2	121.83 (18)	C6—N2—H2B	120.0
O1—C6—C2	120.44 (17)	H2A—N2—H2B	120.0
N2—C6—C2	117.72 (15)	C7—O2—Co1	128.14 (12)
O3—C7—O2	125.20 (18)	Co1—O4—H4A	95 (2)
O3—C7—C8	117.89 (19)	Co1—O4—H4B	118 (2)
O2—C7—C8	116.89 (17)	H4A—O4—H4B	107 (2)
C13—C8—C9	119.34 (19)	O2—Co1—O4	90.97 (6)
C13—C8—C7	120.08 (18)	O2—Co1—O4^i	89.03 (6)
C9—C8—C7	120.55 (19)	O2—Co1—N1	90.72 (6)
C8—C9—C10	120.4 (2)	O4—Co1—N1	89.07 (5)
C8—C9—H9	119.8	O2—Co1—N1^i	89.28 (6)
C10—C9—H9	119.8	O4—Co1—N1^i	90.93 (5)
C11—C10—C9	118.1 (2)
N1—C1—C2—C3	0.1 (3)	C11—C12—C13—C8	0.4 (4)
N1—C1—C2—C6	−178.37 (18)	C9—C8—C13—C12	−1.0 (3)
C1—C2—C3—C4	0.6 (3)	C7—C8—C13—C12	−178.9 (2)
C6—C2—C3—C4	179.02 (19)	C4—C5—N1—C1	0.5 (3)
C2—C3—C4—C5	−0.7 (3)	C4—C5—N1—Co1	−178.28 (17)
C3—C4—C5—N1	0.1 (3)	C2—C1—N1—C5	−0.6 (3)
C1—C2—C6—O1	154.9 (2)	C2—C1—N1—Co1	178.19 (14)
C3—C2—C6—O1	−23.5 (3)	O3—C7—O2—Co1	19.4 (3)
C1—C2—C6—N2	−25.8 (3)	C8—C7—O2—Co1	−158.90 (13)
C3—C2—C6—N2	155.8 (2)	C7—O2—Co1—O4	−9.19 (16)
O3—C7—C8—C13	−8.6 (3)	C7—O2—Co1—O4^i	170.81 (16)
O2—C7—C8—C13	169.84 (18)	C7—O2—Co1—N1	−98.27 (16)
O3—C7—C8—C9	173.5 (2)	C7—O2—Co1—N1^i	81.73 (16)
O2—C7—C8—C9	−8.1 (3)	C5—N1—Co1—O2^i	155.44 (16)
C13—C8—C9—C10	1.0 (4)	C1—N1—Co1—O2^i	−23.30 (15)
C7—C8—C9—C10	178.9 (3)	C5—N1—Co1—O2	−24.56 (16)
C8—C9—C10—C11	−0.3 (5)	C1—N1—Co1—O2	156.70 (15)
C9—C10—C11—F1	179.3 (3)	C5—N1—Co1—O4	−115.52 (15)
C9—C10—C11—C12	−0.3 (5)	C1—N1—Co1—O4	65.75 (14)
C10—C11—C12—C13	0.3 (5)	C5—N1—Co1—O4^i	64.48 (15)
F1—C11—C12—C13	−179.3 (2)	C1—N1—Co1—O4^i	−114.25 (14)

Symmetry code: (i) −x, −y+1, −z+1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
C1—H1···O2^i	0.93	2.50	3.036 (2)	117
N2—H2A···O4^ii	0.86	2.27	2.969 (2)	139
N2—H2B···O1^iii	0.86	2.22	2.883 (2)	134
O4—H4A···O3	0.85 (2)	1.73 (2)	2.571 (2)	171 (3)
O4—H4B···O1^iv	0.85 (2)	1.94 (2)	2.7741 (18)	167 (3)
C5—H5···F1^v	0.93	2.57	3.185 (3)	125
C5—H5···O2	0.93	2.56	3.098 (2)	117

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