Aqua­{4,4′-dimeth­oxy-2,2′-[pyridine-2,3-diylbis(nitrilo­methanylyl­idene)]­diphenolato}copper(II)

Fatiha Benghanem; Razika Benramdane; Sofiane Bouacida; Saida Keraghel; Ali Ourari

doi:10.1107/S1600536812031273

. 2012 Jul 14;68(Pt 8):m1069–m1070. doi: 10.1107/S1600536812031273

Aqua{4,4′-dimethoxy-2,2′-[pyridine-2,3-diylbis(nitrilomethanylylidene)]diphenolato}copper(II)

Fatiha Benghanem ^a, Razika Benramdane ^a, Sofiane Bouacida ^b,^*, Saida Keraghel ^a, Ali Ourari ^a

PMCID: PMC3414130 PMID: 22904737

Abstract

Molecules of the title compound, [Cu(C₂₁H₁₇N₃O₄)(H₂O)], lie across a crystallographic mirror plane. The Cu^II atom is five-coordinated in a distorted square-pyramidal environment by two phenolate O atoms and two imine N atoms of the tetradentate Schiff base anion in the basal plane and one water molecule in the apical position. Because of symmetry, the pyridine N atom and the corresponding C atom at the 4-position of the pyridine ring are disordered. The crystal packing can be described as being composed of alternating layers stacked along [001]. Intramolecular C—H⋯N and intermolecular C—H⋯O and O—H⋯O hydrogen-bonding interactions, as well as C—H⋯π and π–π stacking interactions [shortest centroid–centroid distance = 3.799 (8) Å and interplanar distance = 3.469 (2) Å] are observed.

Related literature

For background, see Ourari et al. (2006 ▶); Ouari et al. (2010 ▶); Ourari, Ouari et al. (2008 ▶); Vyas & Shah (1963 ▶); Kataoka et al. (1979 ▶). For applications, see: Ourari, Baameur et al. (2008 ▶); Coche-Guerente et al. (1995 ▶). For the synthesis, see: Huo et al. (1999 ▶); Khedkar & Radhakrishnan (1997 ▶); Guo & Wong (1999 ▶).

Experimental

Crystal data

[Cu(C₂₁H₁₇N₃O₄)(H₂O)]
M _r = 456.93
Orthorhombic,
a = 23.162 (7) Å
b = 5.0997 (14) Å
c = 7.769 (2) Å
V = 917.7 (4) Å³
Z = 2
Mo Kα radiation
μ = 1.23 mm⁻¹
T = 296 K
0.12 × 0.06 × 0.04 mm

Data collection

Bruker APEXII CCD diffractometer
10830 measured reflections
3026 independent reflections
2384 reflections with I > 2σ(I)
R _int = 0.056

Refinement

R[F ² > 2σ(F ²)] = 0.032
wR(F ²) = 0.060
S = 0.89
3026 reflections
142 parameters
2 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.28 e Å⁻³
Δρ_min = −0.42 e Å⁻³
Absolute structure: Flack (1983 ▶), 1361 Friedel pairs
Flack parameter: −0.015 (11)

Data collection: APEX2 (Bruker, 2001 ▶); cell refinement: SAINT (Bruker, 2001 ▶); data reduction: SAINT; program(s) used to solve structure: SIR2002 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997 ▶) and DIAMOND (Brandenburg & Berndt, 2001 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812031273/wm2656sup1.cif

e-68-m1069-sup1.cif^{(22.1KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812031273/wm2656Isup2.hkl

e-68-m1069-Isup2.hkl^{(145.5KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Cu1—O1	1.9126 (14)
Cu1—N1	1.9561 (16)
Cu1—O3	2.416 (3)

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Table 2. Hydrogen-bond geometry (Å, °).

Cg is the centroid of the C2–C7 benzene ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O3—H1W⋯O1ⁱ	0.84 (2)	2.19 (2)	2.933 (3)	146 (2)
C8—H8A⋯O2ⁱⁱ	0.93	2.57	3.330 (3)	139
C8—H8A⋯N2	0.93	2.49	2.844 (3)	103
C1—H1B⋯Cg ⁱⁱⁱ	0.96	2.71	3.528 (4)	143

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) .

Acknowledgments

The authors thank the Algerian Ministère de l’Enseignement Supérieur et de la Recherche Scientifique for financial support and Professor L. Ouahab (Laboratoire des Sciences Chimiques, Rennes 1, France) for helpful discussions.

supplementary crystallographic information

Comment

The title compound is one of the targeted materials to elaborate modified electrodes in order to use them in heterogeneous electrocatalysis. Therefore, this work is a continuation of investigations where 2,3-diaminophenol and 2,3-diaminopyridine were involved (Ourari et al., 2006; Ouari et al., 2010; Ourari, Ouari et al., 2008). The resulting ligands or complexes may be functionalized by etherification (Vyas & Shah, 1963) or quaternization (Kataoka et al., 1979) reactions using N-(3-bromopropyl)pyrrole. These materials are mainly applied in catalysis, electrocatalysis and sensors (Ourari, Baameur et al., 2008; Coche-Guerente et al., 1995). The synthesis of new salicylaldehyde derivatives containing electropolymerizable units can be considered as the main source of functionalized π-conjugated conducting polymers as those of poly(pyrrole), poly(thiophene) and poly(aniline) (Huo et al., 1999; Khedkar & Radhakrishnan, 1997; Guo & Wong, 1999). We report here the synthesis of the title compound, [Cu(C₂₁H₁₇N₃O₄)(H₂O)], (I) and its crystal structure.

The molecular geometry of (I), and the atomic numbering used, is illustrated in Fig. 1. The asymmetric unit of (I) consists of one-half of the molecule, with the other half generated by a crystallographic mirror plane. Due to this symmetry the N2 and C10 atoms of the pyridine ring are equally disordered. The Cu^II atom is five-coordinate in a distorted square pyramidal geometry by the O atoms of two 5-methoxysalicylidene groups, the imine N atoms and one molecule of water in the apical position. The bond lengths of the coordination sphere range from 1.9126 (14) to 2.416 (3) Å for Cu—O distances and is 1.9561 (16) Å for the Cu—N distance. The crystal packing in (I) can be described by alterning layers along [001] (Fig. 2). There are one intramolecular C—H···N and two intermolecular C—H···O and O—H···O hydrogen bonding interactions in this packing (Fig. 3), which is further stabilized by C—H···π interactions (Table 2) and π–π stacking (shortest centroid-to-centroid distance 3.799 (8); interplanar distance of 3.469 (2) Å).

Experimental

All reagents were obtained from commercial sources and used without any further purification. 59 mg (0.3 mmol) of copper acetate monohydrate were dissolved in MeOH (10 ml). This solution was added dropwise to a stirred methanolic solution (5 ml) containing 113 mg (0.3 mmol) of the Schiff base ligand (N,N-bis(5-Methoxysalicyidene)-2,3-diaminopyridine). This mixture was stirred and refluxed for 90 minutes under nitrogen atmosphere to give a brown precipitate which was collected by filtration and washed successively with methanol and diethyl ether. After drying in vacuum in the presence of CaCl₂, 93.5 mg of the copper complex were obtained (71%). Suitable crystals of green color were obtained from the filtrate after about twenty days. The microanalysis of (I) showed that one molecule of water is present (calc. / found %: C:55.20 /54.78; H:04.19 / 04.12; N: 09.20 / 09.17). Moreover, analysis by infrared spectrometry showing a spectrum with an absorption band at 1628 cm^-1 attesting the presence of lattice water with its characteristic vibration band (H—O—H bending) accompanied by the stretching band at about 3500 cm^-1 (Fig. 4).