A one-dimensional zigzag coordination polymer: catena-poly­[[di­aqua­pyridine­nickel(II)]-[mu]-pyridine-2,3-di­carboxyl­ato-[kappa]³N,O²:O³]

The asymmetric unit of the title one-dimensional coordination polymer, [Ni(C₇H₃NO₄)(C₅H₅N)(H₂O)₂]_n, contains a quino­linate dianion, a nickel(II) ion, two water mol­ecules and a pyridine mol­ecule. The pyridine-2,3-di­carboxyl­ate (quino­linate) ligands connect the nickel(II) ions in a head-to-tail fashion, resulting in the formation of a one-dimensional zigzag chain. Adjacent chains form pairs via an extensive network of hydrogen-bonding interactions. A weak C-H...O intermolecular hydrogen bond links neighboring pairs of chains, thus generating two-dimensional double-sheet layers that are stabilized via [pi]-[pi]-stacking interactions between adjacent quinolinate pyridyl rings.

S1. Comment

The design and synthesis of new coordination polymers based on transition metal compounds and multidentate organic ligands have attracted much interest in recent years because of their intriguing molecular topologies and their potential applications as novel functional materials (Batten & Robson, 1998; Hagrman et al., 1999). One of the major goals in the field of polymeric chemistry is to gain control over the structure of the infinite array itself, as well as to be able to control the packing arrangement of the polymeric entities in the solid-state structure (Moulton & Zaworotko, 2001). In order to establish general principles for more complicated systems, it is useful to first exploit the simplest topological type of coordination polymers, i.e. one-dimensional chain-like structures (Khlobystov et al., 2001). In general, it is possible to assemble an infinite structure from a linear multidentate ligand, such as 4,4'-bipyridine (Robinson & Zaworotko, 1995) or 1,4-benzenedicarboxylate (Li et al., 1999), together with suitable metal ions. In some cases, non-linear multidentate ligands, such as quinolinate (pyridine-2,3-dicarboxylate), can also be good linkers because they can tolerate a distortion in their molecular geometry that resulting in an expansion of the angle between their coordination sites (Gutschke et al., 1995; Sileo et al., 1999; Jaber et al., 1996). We report here the structure of such a quinolinate-containing zigzag chain-like coordination polymer, namely Ni(C₇H₃NO₄)(C₅H₅N)(H₂O)₂, (I).

As shown in Fig. 1, the Ni^II atom adopts a slightly distorted octahedral geometry and is coordinated to four O atoms, of which atoms O1 and O4ⁱ [symmetry code: (i) x, y, 1 + z] belong to the two carboxylate groups on the quinolinate ligand, and two are water molecules. Two N atoms complete the sixfold coordination sphere around the metal ion, viz. pyridine atom N1 and pyridyl atom N2 of to the quinolinate ligand. Thus, the quinolinate ligand acts as a bridge, via atom O4, linking neighboring Ni^II atoms in a head-to-tail mode, resulting in an infinite zigzag chain running along the c axis. The O1/C11/O3 carboxylate group is coplanar with the pyridyl plane, but steric interaction between the two carboxylate groups forces the O2/C12/O4 group to lie almost perpendicular to the pyridyl ring, with a dihedral angle of 86.43 (8)° between the pyridyl and the carboxyl planes. The pyridine molecule coordinates to the Ni^II atom along an axial direction of the distorted octahedron, with atom O2W below the equatorial plane. Consecutive equatorial planes (Ni, O1, O2W, N2, O4ⁱ) in the chains are coplanar. The elongated bond distance between the two sp² C atoms, C10—C11, has also been observed for an earlier metal–quinolinate coordination polymer (Jaber et al., 1996). Similar bond distances are reported for related compounds in previous studies [1.538 (9) Å (Ravikumar et al., 1995) and 1.535 (3) Å (Neels et al., 1997)].

The packing structure of (I) is dominated by extensive hydrogen bonding (Table 2). There are two intrachain hydrogen bonds, namely O1W—H1WB···O2 and O2W—H2WA···O3, which participate in controlling the conformation of the chains extending along the c axis. Two adjacent chains are connected along the b axis, thus forming a pair of chains via four interchain hydrogen bonds (O1W—H1WA···O2, O1W—H1WA···O3, O2W—H2WB···O1 and O2W—H2WB···O3), as depicted in Fig. 2. The Ni···Ni intrachain distance is 7.667 (2) Å, whereas the Ni···Ni interchain distance is shorther [6.265 (2) Å].

A weak C4—H4···O1 hydrogen bond connects the chains approximately along the a axis in an antiparallel mode, forming a two-dimensional double-sheet in the bc plane, with the sheets layered along the c axis (Fig. 3). The centroid–centroid distance between two adjacent quinolinate pyridyl rings in different layers is 3.861 (1) Å, indicating the presence of π–π-packing interactions between the two-dimensional double-sheet layers (Janiak, 2000). In contrast, the centroid–centroid distance between the pyridine rings of two adjacent pairs of molecules stacked along the c axis is 4.016 (8) Å, indicating that there is no π–π interaction.

S2. Experimental

Ni(ClO₄)₂^.6(H₂O) (109.6 mg, 0.30 mmol), quinolinic acid (51.3 mg, 0.30 mmol) and pyridine (0.4 ml) were dissolved in a mixture of water (6 ml) and ethanol (3 ml). The mixture was placed in a Teflon-lined stainless steel vessel (25 ml), which was sealed and heated to 403 K for 72 h, after which time it was cooled to room temperature. Blue block crystals were collected by filtration, and then washed with water and ethanol to afford (I) in (yield ca 80%).

S3. Refinement

H atoms bonded to C atoms were introduced at calculated positions and treated as riding, with C—H distances of 0.93 Å. All of the water H atoms were found in difference maps at an intermediate stage of the refinement and were refined subject to an O—H DFIX restraint of 0.88 (3) Å and an angular H—O—H DFIX restraint [H—H 1.39 (3) Å]. The U_iso values of the water H atoms were refined but, in all other cases, the U_iso(H) value was taken to be 1.2U_eq of the parent atom.

Computing details

Data collection: CAD-4 Software (Enraf-Nonius, 1989); cell refinement: CAD-4 Software; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: Bruker SHELXTL (Sheldrick, 2000); software used to prepare material for publication: Bruker SHELXTL.

Figures

	Fig. 1. The asymmetric unit of (I) (solid line portion), with displacement ellipsoids shown at the 30% probability level. [Symmetry code: (i) x, y, 1 + z.]
	Fig. 2. A perspective view of the hydrogen bonds generating a pair of chains. H atoms unrelated to these hydrogen bonds have been omitted for clarity.
	Fig. 3. A packing diagram of (I), viewed along the c axis, illustrating the weak hydrogen bonds along a and interlayer π–π interactions. H atoms not involved in hydrogen bonding have been omitted for clarity.

catena-poly[[diaquapyridinenickel(II)]- µ-pyridine-2,3-dicarboxylato-κ³N,O²:O³]

Crystal data

[Ni(C7H3NO4)(C5H5N)(H2O)2]	F(000) = 696
Mr = 338.95	Dx = 1.699 Mg m^−3
Monoclinic, P21/c	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ybc	Cell parameters from 25 reflections
a = 15.240 (3) Å	θ = 1.3–13.5°
b = 11.424 (2) Å	µ = 1.49 mm^−1
c = 7.6670 (15) Å	T = 298 K
β = 96.79 (3)°	Block, blue
V = 1325.5 (5) Å^3	0.13 × 0.12 × 0.10 mm
Z = 4

Data collection

Enraf–Nonius CAD-4 diffractometer	1356 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	Rint = 0.043
Graphite monochromator	θmax = 25.0°, θmin = 1.4°
ω scans	h = −18→17
Absorption correction: ψ scan XCAD4 (Harms & Wocadlo, 1995)	k = −13→0
Tmin = 0.819, Tmax = 0.860	l = 0→9
2520 measured reflections	3 standard reflections every 200 reflections
2326 independent reflections	intensity decay: 1.0%

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.045	Hydrogen site location: inferred from neighbouring sites
wR(F^2) = 0.103	H atoms treated by a mixture of independent and constrained refinement
S = 1.00	w = 1/[σ^2(Fo^2) + (0.0297P)^2] where P = (Fo^2 + 2Fc^2)/3
2326 reflections	(Δ/σ)max = 0.050
206 parameters	Δρmax = 0.36 e Å^−3
6 restraints	Δρmin = −0.37 e Å^−3

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
Ni	0.25688 (4)	0.46691 (6)	0.22588 (8)	0.0263 (2)
C1	0.1924 (4)	0.7158 (5)	0.2152 (8)	0.0480 (17)
H1	0.2522	0.7326	0.2424	0.058*
C2	0.1340 (4)	0.8068 (6)	0.1835 (9)	0.064 (2)
H2	0.1543	0.8837	0.1888	0.077*
C3	0.0466 (4)	0.7846 (6)	0.1447 (9)	0.062 (2)
H3	0.0064	0.8454	0.1215	0.074*
C4	0.0187 (4)	0.6701 (6)	0.1401 (9)	0.060 (2)
H4	−0.0409	0.6517	0.1157	0.073*
C5	0.0801 (4)	0.5849 (6)	0.1719 (7)	0.0454 (16)
H5	0.0610	0.5075	0.1684	0.054*
C6	0.4039 (3)	0.6160 (4)	0.0941 (7)	0.0315 (13)
H6	0.4161	0.6443	0.2081	0.038*
C7	0.4571 (4)	0.6488 (5)	−0.0280 (7)	0.0355 (14)
H7	0.5037	0.7004	0.0018	0.043*
C8	0.4413 (3)	0.6049 (5)	−0.1959 (7)	0.0299 (13)
H8	0.4774	0.6259	−0.2804	0.036*
C9	0.3708 (3)	0.5291 (5)	−0.2378 (6)	0.0249 (11)
C10	0.3180 (3)	0.5025 (4)	−0.1106 (6)	0.0213 (12)
C11	0.2396 (3)	0.4185 (5)	−0.1342 (7)	0.0279 (12)
C12	0.3590 (3)	0.4749 (5)	−0.4194 (6)	0.0260 (11)
N1	0.1669 (3)	0.6055 (4)	0.2083 (5)	0.0318 (11)
N2	0.3347 (3)	0.5446 (4)	0.0561 (5)	0.0277 (10)
O1	0.2008 (2)	0.3982 (3)	−0.0038 (4)	0.0341 (9)
O2	0.3966 (3)	0.3797 (4)	−0.4339 (5)	0.0536 (12)
O3	0.2205 (2)	0.3739 (3)	−0.2812 (4)	0.0433 (11)
O4	0.3160 (2)	0.5327 (3)	−0.5393 (4)	0.0293 (8)
O1W	0.3507 (3)	0.3324 (4)	0.2382 (5)	0.0383 (10)
O2W	0.1741 (2)	0.3623 (3)	0.3561 (5)	0.0319 (9)
H1WA	0.341 (4)	0.257 (2)	0.223 (7)	0.07 (2)*
H1WB	0.371 (4)	0.339 (4)	0.351 (3)	0.06 (2)*
H2WA	0.187 (4)	0.372 (4)	0.468 (3)	0.06 (2)*
H2WB	0.185 (3)	0.288 (2)	0.339 (6)	0.046 (19)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ni	0.0276 (4)	0.0274 (4)	0.0241 (4)	−0.0012 (4)	0.0034 (3)	−0.0013 (4)
C1	0.031 (4)	0.037 (4)	0.073 (5)	−0.004 (3)	−0.004 (3)	−0.008 (3)
C2	0.047 (4)	0.033 (4)	0.109 (6)	−0.002 (3)	−0.007 (4)	−0.009 (4)
C3	0.046 (4)	0.045 (5)	0.090 (5)	0.020 (4)	−0.010 (4)	−0.007 (4)
C4	0.026 (4)	0.058 (5)	0.094 (5)	0.005 (4)	−0.004 (4)	−0.007 (4)
C5	0.039 (4)	0.040 (4)	0.056 (4)	−0.006 (3)	0.004 (3)	0.000 (3)
C6	0.038 (3)	0.028 (3)	0.027 (3)	−0.008 (3)	−0.002 (3)	−0.006 (3)
C7	0.036 (3)	0.029 (3)	0.041 (3)	−0.011 (3)	−0.001 (3)	−0.001 (3)
C8	0.029 (3)	0.028 (3)	0.032 (3)	−0.004 (3)	0.004 (3)	0.009 (3)
C9	0.028 (3)	0.022 (3)	0.023 (3)	0.005 (3)	−0.001 (2)	0.003 (3)
C10	0.026 (3)	0.019 (3)	0.018 (3)	0.003 (2)	0.001 (2)	0.001 (2)
C11	0.031 (3)	0.028 (3)	0.024 (3)	0.003 (3)	−0.001 (2)	−0.001 (2)
C12	0.030 (3)	0.027 (3)	0.022 (3)	−0.008 (3)	0.004 (2)	−0.001 (3)
N1	0.027 (3)	0.037 (3)	0.030 (3)	0.001 (2)	−0.002 (2)	−0.004 (2)
N2	0.031 (2)	0.027 (3)	0.024 (2)	−0.002 (2)	0.0004 (19)	−0.002 (2)
O1	0.037 (2)	0.039 (2)	0.027 (2)	−0.0088 (19)	0.0065 (17)	−0.0035 (18)
O2	0.076 (3)	0.044 (3)	0.038 (2)	0.030 (2)	−0.005 (2)	−0.006 (2)
O3	0.052 (3)	0.048 (3)	0.030 (2)	−0.022 (2)	0.0050 (19)	−0.0090 (19)
O4	0.037 (2)	0.0259 (19)	0.0240 (18)	0.001 (2)	−0.0019 (16)	0.0012 (18)
O1W	0.041 (2)	0.033 (3)	0.040 (3)	0.003 (2)	0.002 (2)	−0.0064 (19)
O2W	0.035 (2)	0.029 (2)	0.031 (2)	−0.0013 (19)	0.0012 (19)	0.0002 (18)

Geometric parameters (Å, º)

Ni—O1	2.023 (3)	C6—H6	0.9300
Ni—O4^i	2.058 (3)	C7—C8	1.376 (7)
Ni—N1	2.089 (4)	C7—H7	0.9300
Ni—N2	2.062 (4)	C8—C9	1.389 (7)
Ni—O1W	2.093 (4)	C8—H8	0.9300
Ni—O2W	2.077 (4)	C9—C10	1.369 (6)
C1—N1	1.318 (7)	C9—C12	1.515 (6)
C1—C2	1.372 (8)	C10—N2	1.362 (6)
C1—H1	0.9300	C10—C11	1.527 (7)
C2—C3	1.353 (8)	C11—O1	1.242 (5)
C2—H2	0.9300	C11—O3	1.240 (6)
C3—C4	1.375 (9)	C12—O2	1.240 (6)
C3—H3	0.9300	C12—O4	1.252 (6)
C4—C5	1.352 (8)	O4—Ni^ii	2.058 (3)
C4—H4	0.9300	O1W—H1WA	0.878 (19)
C5—N1	1.340 (6)	O1W—H1WB	0.884 (19)
C5—H5	0.9300	O2W—H2WA	0.867 (19)
C6—N2	1.338 (6)	O2W—H2WB	0.880 (19)
C6—C7	1.362 (7)
O1—Ni—N1	91.80 (16)	C6—C7—C8	119.4 (5)
O1—Ni—N2	80.40 (15)	C6—C7—H7	120.3
O1—Ni—O4^i	178.42 (15)	C8—C7—H7	120.3
O1—Ni—O2W	88.67 (15)	C7—C8—C9	119.3 (5)
O4^i—Ni—N2	99.79 (14)	C7—C8—H8	120.4
O4^i—Ni—O2W	91.00 (14)	C9—C8—H8	120.4
N2—Ni—O2W	168.02 (16)	C10—C9—C8	118.5 (4)
N2—Ni—N1	93.16 (17)	C10—C9—C12	123.2 (4)
O1—Ni—O1W	88.31 (16)	C8—C9—C12	118.2 (4)
O2W—Ni—N1	92.05 (17)	N2—C10—C9	122.0 (4)
O2W—Ni—O1W	90.36 (15)	N2—C10—C11	112.9 (4)
O4^i—Ni—N1	89.76 (15)	C9—C10—C11	124.9 (4)
O4^i—Ni—O1W	90.14 (15)	O3—C11—O1	124.9 (5)
N2—Ni—O1W	84.48 (16)	O3—C11—C10	117.5 (5)
N1—Ni—O1W	177.59 (17)	O1—C11—C10	117.6 (4)
N1—C1—C2	122.4 (6)	O2—C12—O4	127.1 (5)
N1—C1—H1	118.8	O2—C12—C9	115.8 (4)
C2—C1—H1	118.8	O4—C12—C9	117.0 (5)
C3—C2—C1	119.8 (6)	C1—N1—C5	117.1 (5)
C3—C2—H2	120.1	C1—N1—Ni	122.3 (4)
C1—C2—H2	120.1	C5—N1—Ni	120.3 (4)
C2—C3—C4	118.6 (6)	C6—N2—C10	118.3 (4)
C2—C3—H3	120.7	C6—N2—Ni	128.5 (3)
C4—C3—H3	120.7	C10—N2—Ni	112.5 (3)
C5—C4—C3	118.4 (6)	C11—O1—Ni	115.8 (3)
C5—C4—H4	120.8	C12—O4—Ni^ii	125.9 (3)
C3—C4—H4	120.8	Ni—O1W—H1WA	128 (4)
N1—C5—C4	123.8 (6)	Ni—O1W—H1WB	98 (4)
N1—C5—H5	118.1	H1WA—O1W—H1WB	104 (3)
C4—C5—H5	118.1	Ni—O2W—H2WA	109 (4)
N2—C6—C7	122.4 (5)	Ni—O2W—H2WB	111 (3)
N2—C6—H6	118.8	H2WA—O2W—H2WB	105 (3)
C7—C6—H6	118.8
N1—C1—C2—C3	0.4 (11)	O1—Ni—N1—C5	48.6 (4)
C1—C2—C3—C4	0.8 (11)	O4^i—Ni—N1—C5	−131.1 (4)
C2—C3—C4—C5	−1.0 (11)	N2—Ni—N1—C5	129.1 (4)
C3—C4—C5—N1	0.2 (10)	O2W—Ni—N1—C5	−40.1 (4)
N2—C6—C7—C8	−1.9 (8)	C7—C6—N2—C10	0.9 (7)
C6—C7—C8—C9	0.7 (8)	C7—C6—N2—Ni	170.8 (4)
C7—C8—C9—C10	1.4 (7)	C9—C10—N2—C6	1.4 (7)
C7—C8—C9—C12	−175.4 (5)	C11—C10—N2—C6	177.8 (4)
C8—C9—C10—N2	−2.5 (7)	C9—C10—N2—Ni	−170.2 (4)
C12—C9—C10—N2	174.2 (5)	C11—C10—N2—Ni	6.3 (5)
C8—C9—C10—C11	−178.4 (5)	O1—Ni—N2—C6	−177.8 (5)
C12—C9—C10—C11	−1.8 (8)	O4^i—Ni—N2—C6	0.6 (4)
N2—C10—C11—O3	−178.6 (4)	O2W—Ni—N2—C6	−153.4 (7)
C9—C10—C11—O3	−2.3 (7)	N1—Ni—N2—C6	90.9 (4)
N2—C10—C11—O1	−0.1 (6)	O1W—Ni—N2—C6	−88.6 (4)
C9—C10—C11—O1	176.2 (5)	O1—Ni—N2—C10	−7.4 (3)
C10—C9—C12—O2	−86.0 (6)	O4^i—Ni—N2—C10	171.1 (3)
C8—C9—C12—O2	90.7 (6)	O2W—Ni—N2—C10	17.0 (9)
C10—C9—C12—O4	97.0 (6)	N1—Ni—N2—C10	−98.6 (3)
C8—C9—C12—O4	−86.3 (6)	O1W—Ni—N2—C10	81.9 (3)
C2—C1—N1—C5	−1.2 (9)	O3—C11—O1—Ni	172.0 (4)
C2—C1—N1—Ni	172.3 (5)	C10—C11—O1—Ni	−6.4 (6)
C4—C5—N1—C1	0.9 (9)	N2—Ni—O1—C11	7.6 (4)
C4—C5—N1—Ni	−172.7 (5)	O2W—Ni—O1—C11	−167.5 (4)
O1—Ni—N1—C1	−124.7 (4)	N1—Ni—O1—C11	100.5 (4)
O4^i—Ni—N1—C1	55.6 (4)	O1W—Ni—O1—C11	−77.1 (4)
N2—Ni—N1—C1	−44.2 (5)	O2—C12—O4—Ni^ii	23.1 (7)
O2W—Ni—N1—C1	146.6 (4)	C9—C12—O4—Ni^ii	−160.2 (3)

Symmetry codes: (i) x, y, z+1; (ii) x, y, z−1.

Hydrogen-bond geometry (Å, º)

D—H···A	D—H	H···A	D···A	D—H···A
O1W—H1WB···O2^i	0.88 (2)	1.72 (2)	2.586 (5)	167 (5)
O1W—H1WA···O2^iii	0.88 (2)	2.20 (4)	2.885 (6)	134 (5)
O1W—H1WA···O3^iii	0.88 (2)	2.37 (4)	3.073 (6)	138 (5)
O2W—H2WB···O1^iii	0.88 (2)	2.44 (3)	3.173 (5)	141 (4)
O2W—H2WA···O3^i	0.87 (2)	1.93 (2)	2.790 (5)	173 (5)
O2W—H2WB···O3^iii	0.88 (2)	2.16 (2)	3.010 (5)	162 (4)
C4—H4···O1^iv	0.93	2.55	3.473 (7)	172

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