4-(4-Pyrid­yl)pyridinium bis­(pyridine-2,6-dicarboxyl­ato)chromium(III) tetra­hydrate

Janet Soleimannejad; Hossein Aghabozorg; Shabnam Hooshmand

doi:10.1107/S1600536808006594

. 2008 Mar 20;64(Pt 4):m564–m565. doi: 10.1107/S1600536808006594

4-(4-Pyridyl)pyridinium bis(pyridine-2,6-dicarboxylato)chromium(III) tetrahydrate

Janet Soleimannejad ^a,^*, Hossein Aghabozorg ^b, Shabnam Hooshmand ^a

PMCID: PMC2960993 PMID: 21202019

Abstract

The title compound, (C₁₀H₉N₂)[Cr(C₇H₃NO₄)₂]·4H₂O or (4,4′-bipyH)[Cr(pydc)₂]·4H₂O (where 4,4′-bipy is 4,4′-bipyridine and pydcH₂ is pyridine-2,6-dicarboxylic acid), was synthesized by the reaction of chromium(III) chloride hexahydrate with pyridine-2,6-dicarboxylic acid and 4,4′-bipyridine in a 1:2:4 molar ratio in aqueous solution. This compound is composed of an anionic complex, [Cr(pydc)₂]⁻, protonated 4,4′-bipyridine as a counter-ion, (4,4′-bipyH)⁺, and four uncoordinated water molecules. The anion is a six-coordinate complex with a distorted octahedral geometry around the Cr^III atom, formed by two tridentate pyridine-2,6-dicarboxylate, pydc²⁻, groups. Intermolecular O—H⋯O, N—H⋯O and C—H⋯O hydrogen bonds, and C—O⋯π stacking interactions (with distances of 3.3390 (13) and 3.4575 (13) Å) connect the various components into a supramolecular structure.

Related literature

For related literature, see: Aghabozorg, Attar Gharamaleki, Ghadermazi et al. (2007 ▶); Aghabozorg, Attar Gharamaleki, Ghasemikhah et al. (2007 ▶); Soleimannejad et al. (2007 ▶).

Experimental

Crystal data

(C₁₀H₉N₂)[Cr(C₇H₃NO₄)₂]·4H₂O
M _r = 611.46
Triclinic,
a = 9.3785 (19) Å
b = 9.4106 (19) Å
c = 14.542 (3) Å
α = 84.71 (3)°
β = 89.78 (3)°
γ = 87.25 (3)°
V = 1276.5 (4) Å³
Z = 2
Mo Kα radiation
μ = 0.52 mm⁻¹
T = 150 (2) K
0.32 × 0.28 × 0.16 mm

Data collection

Bruker SMART APEXII diffractometer
Absorption correction: multi-scan (SADABS; Sheldrick, 1996 ▶) T _min = 0.851, T _max = 0.921
31765 measured reflections
10833 independent reflections
8883 reflections with I > 2σ(I)
R _int = 0.026

Refinement

R[F ² > 2σ(F ²)] = 0.038
wR(F ²) = 0.102
S = 1.05
10833 reflections
370 parameters
H-atom parameters constrained
Δρ_max = 0.60 e Å⁻³
Δρ_min = −0.57 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: SHELXTL (Sheldrick, 2008 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808006594/om2216sup1.cif

e-64-0m564-sup1.cif^{(26.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808006594/om2216Isup2.hkl

e-64-0m564-Isup2.hkl^{(819.7KB, hkl)}

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N4—H4A⋯O11ⁱ	0.88	1.82	2.6736 (14)	164
O9—H9B⋯O1	0.85	1.95	2.7944 (15)	173
O9—H9A⋯O10ⁱⁱ	0.85	1.98	2.8336 (16)	176
O10—H10B⋯O6	0.85	1.86	2.7035 (16)	172
O10—H10A⋯N3	0.85	1.94	2.7610 (15)	162
O11—H11A⋯O10ⁱⁱⁱ	0.85	1.87	2.7132 (15)	172
O11—H11B⋯O3	0.85	1.95	2.7282 (16)	152
O12—H12B⋯O4	0.85	2.14	2.9569 (16)	160
O12—H12A⋯O7^iv	0.85	2.21	3.0284 (16)	162
C3—H3⋯O8^v	0.95	2.39	3.1688 (16)	139
C5—H5⋯O5^vi	0.95	2.50	3.1737 (16)	128
C10—H10⋯O12^vii	0.95	2.58	3.2867 (16)	132
C11—H11⋯O9^viii	0.95	2.58	3.2271 (17)	126
C15—H15⋯O7^ix	0.95	2.39	3.3002 (17)	160
C16—H16⋯O9^x	0.95	2.49	3.4235 (18)	169
C20—H20⋯O2^xi	0.95	2.51	3.0576 (16)	117
C20—H20⋯O11^xii	0.95	2.45	3.2615 (17)	143
C24—H24⋯O6	0.95	2.56	3.3634 (17)	143

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) ; (viii) ; (ix) ; (x) ; (xi) ; (xii) .

supplementary crystallographic information

Comment

The molecular structure of the title compound is shown in Fig. 1. Hydrogen bond lengths are given in Table 1. According to the crystal structure, the title compound is composed of an anionic complex, [Cr(pydc)₂]^-, protonated 4,4'-bipyridine as a counter ion, (4,4'-bipyH)⁺, and four uncoordinated water molecules.

The Cr^III atom is six-coordinated by two pyridine-2,6-dicarboxylate, pydc^2-, groups which act as a tridentate ligand through two O and one N atoms. The O8—Cr1—O1—C1 and O8—Cr1—O4—C7 torsion angles (-89.13 (9)° and 95.98 (9)°, repectively) show that these two pydc^2- groups are perpendicular. So the anionic complex has distorted octahedral geometry around Cr^III atom. For balancing the anionic complex, a protonated 4,4'-bipyridinium, (4,4'-bipyH)⁺, exists.

In the crystal structure of (4,4'-bipyH)[Cr(pydc)₂].4H₂O complex, the spaces between two layers of [Cr(pydc)₂]^- anions are filled with (4,4'-bipyH)⁺ cations and water molecules (Fig. 2). The angle between two planes passing through aromatic rings of (4,4'-bipyH)⁺ is 51.45 (6)^°, indicating the flexibility of the C—C bond between two rings.

A considerable feature of title compound is the presence of C—O···π stacking interactions between C1—O2 and C7—O3 and Cg1 [Cg1 is centroid for N1/C2—C6 ring] with O···π distances of 3.3390 (13) Å (1 - x, 1 - y, -z) and 3.4575 (13) Å (-x, 1 - y, -z), respectively (Fig. 3).

Intermolecular O—H···O, N—H···O and C—H···O hydrogen bonds with D···A ranging from 2.6736 (14) Å to 3.4235 (18) Å (Table 1), ion pairing and C—O···π stacking interactions seem to be effective in the stabilization of the crystal structure, resulting in the formation of an interesting supramolecular structure.

Experimental

A solution of CrCl₃.6H₂O (133 mg, 0.5 mmol) in water (5 ml) was added to an aqueous solution of pyridine-2,6-dicarboxylic acid (167 mg, 1 mmol) and 4,4'-bipyridine (312 mg, 2 mmol) in water (10 ml) in a 1:2:4 molar ratio and refluxed for an hour. Purple crystals of the title compound were obtained after allowing the mixture to stand for two weeks at room temperature.