Acetato(aqua){6,6′-dimeth­oxy-2,2′-[ethane-1,2-diylbis(nitrilo­methanylyl­idene)]diphenolato}cobalt(III) methanol disolvate

Gervas Assey; Ray J Butcher; Yilma Gultneh

doi:10.1107/S1600536812027687

. 2012 Jun 23;68(Pt 7):m962–m963. doi: 10.1107/S1600536812027687

Acetato(aqua){6,6′-dimethoxy-2,2′-[ethane-1,2-diylbis(nitrilomethanylylidene)]diphenolato}cobalt(III) methanol disolvate

Gervas Assey ^a, Ray J Butcher ^b,^*, Yilma Gultneh ^b

PMCID: PMC3393214 PMID: 22807782

Abstract

In the title complex, [Co(C₁₈H₁₈N₂O₄)(C₂H₃O₂)(H₂O)]·2CH₃OH, the Co^III atom is hexacoordinated by water and acetate groups in the axial positions and by the tetradentate Schiff base occupying equatorial positions. These axial bonds are longer than the equatorial bonds to the tetradentate Schiff base. Two molecules form a dimer through strong hydrogen bonds from the coordinated water of one molecule to the methoxy O atoms of an adjoining molecule. There is extensive intra- and intermolecular O—H⋯O hydrogen bonding between the coordinated water and acetate ligands and the methanol solvent molecules. In addition, there are weak intermolecular C—H⋯O interactions, which link the molecules into a three-dimensional array.

Related literature

For reports on O₂ binding of related cobalt complexes, see: Huie et al. (1979 ▶); Lindblom et al. (1971 ▶). For related dimeric structures formed through hydrogen bonding, see: Huie et al. (1979 ▶); Assey et al. (2010b ▶). For structurally related complexes with included hydrogen-bonded solvent molecules, see: Assey et al. (2010a ▶,b ▶); Ayikoe et al. (2010 ▶); Bao et al. (2009 ▶); Ayikoé et al. (2011 ▶). For the use of cobalt(III)–salen complexes as catalysts, see: Morandi et al. (2011 ▶); Haak et al. (2010 ▶) and for the potential applications of cobalt–Schiff base complexes for magnetic and/or conducting devices, see: Nabei et al. (2009 ▶); Lin et al. (2011 ▶).

Experimental

Crystal data

[Co(C₁₈H₁₈N₂O₄)(C₂H₃O₂)(H₂O)]·2CH₄O
M _r = 526.42
Monoclinic,
a = 9.6306 (3) Å
b = 13.4129 (5) Å
c = 17.9746 (7) Å
β = 90.716 (3)°
V = 2321.67 (15) Å³
Z = 4
Mo Kα radiation
μ = 0.80 mm⁻¹
T = 115 K
0.49 × 0.45 × 0.38 mm

Data collection

Oxford Diffraction Xcalibur diffractometer with a Ruby (Gemini Mo) detector
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2007 ▶) T _min = 0.916, T _max = 1.000
16513 measured reflections
7669 independent reflections
5549 reflections with I > 2σ(I)
R _int = 0.027

Refinement

R[F ² > 2σ(F ²)] = 0.040
wR(F ²) = 0.106
S = 1.00
7669 reflections
322 parameters
3 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.86 e Å⁻³
Δρ_min = −0.45 e Å⁻³

Data collection: CrysAlis PRO (Oxford Diffraction, 2007 ▶); cell refinement: CrysAlis PRO; data reduction: CrysAlis PRO; 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: SHELXTL.

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536812027687/jj2140sup1.cif

e-68-0m962-sup1.cif^{(25.6KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812027687/jj2140Isup2.hkl

e-68-0m962-Isup2.hkl^{(375.2KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Co—O2	1.8839 (8)
Co—N1	1.8870 (10)
Co—O1	1.8892 (8)
Co—N2	1.8910 (10)
Co—O11	1.8995 (8)
Co—O1W	1.9454 (8)

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

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1S—H1S⋯O12	0.84	1.83	2.6671 (14)	174
O2S—H2S⋯O1S	0.84	1.95	2.7682 (17)	165
O1W—H1W1⋯O1ⁱ	0.80 (1)	1.99 (1)	2.7334 (11)	153 (1)
O1W—H1W1⋯O3ⁱ	0.80 (1)	2.32 (1)	2.9124 (13)	131 (1)
O1W—H1W2⋯O2ⁱ	0.80 (1)	2.18 (2)	2.8071 (11)	136 (1)
O1W—H1W2⋯O4ⁱ	0.80 (1)	2.17 (1)	2.8840 (12)	148 (2)
C9—H9A⋯O1S ⁱⁱ	0.99	2.52	3.2610 (16)	132
C13—H13A⋯O11ⁱⁱⁱ	0.95	2.61	3.5380 (15)	165
C12A—H12B⋯O1	0.98	2.38	3.1807 (15)	139
C8—H8A⋯O2S ^iv	0.95	2.55	3.4335 (16)	155
C10—H10A⋯O2S ⁱⁱ	0.99	2.61	3.5119 (17)	151
C12A—H12C⋯O2S ^v	0.98	2.62	3.5541 (19)	161

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

Acknowledgments

RJB wishes to acknowledge the NSF–MRI program (grant CHE-0619278) for funds to purchase the diffractometer.

supplementary crystallographic information

Comment

Cobalt Schiff base complexes are of great importance because of their involvement in biological systems. One of their reactions of biological importance is that of binding O₂ to a metal chelate (Lindblom et al. 1971). In recent years, there have been reports about many studies of metal complexes with di-oxygen as one ligand (Huie et al., 1979). The reason behind these studies is to understand the binding between oxygen and transition metals in the proteins that are involved in oxygen transport in living creatures. Another area where the cobalt Schiff bases have find application is that of organic reactions catalysis (Haak et al. 2010). Cobalt(III) salen complexes have been described in the literature as catalysts for enantioselective cyclopropagation with diazoacetates in organic media (Morandi et al. 2011). Cobalt Schiff base complexes have also been investigated with respect to their potential application for magnetic and/or conducting devices (Nabei et al., 2009; Lin et al., 2011).

In view of the importance of cobalt Schiff base complexes the structure of the title compound, CoC₂₀ H₂₃N₂O₇^.2(CH₃OH), has been determined. Schiff base ligands containing a methoxy or ethoxy substituent in the 3 position in the aromatic ring and in a cis conformation about the central metal are often involved in interactions where these substituent are either coordinated to a metal (Assey et al., 2010a,b; Ayikoe, et al., 2010) or form strong hydrogen bonds to a water molecule (or some other suitable solvent such as dimethylformamide) in the cavity created by this conformation (Bao et al., 2009; Ayikoé et al., 2011). In this case, as is found in related Mn and Co complexes (Assey et al., 2010b; Huie, et al., 1979), this is achieved by two metal complexes coming together to form a hydrogen bonded dimer. The axially coordinated water molecules of each metal complex form strong hydrogen bonds to the two methoxy groups of the adjoining complex (O1W···O1 2.7335 (11), O1W···O3 2.9124 (13), O1W··· O2 2.8071 (11), O1W···O4 2.8840 (12) Å).

The structure consists of six coordinate Co(III) in a slightly distorted octahedral geometry with both methanol and water occupying the axial positions and a tetradentate Schiff base (N₂O₂) which is in the equatorial plane. In addition there are two molecules of solvate methanol in the lattice (Fig. 1). From Table 1 it can be seen that the equatorial metal ligand bond lengths are very similar and vary from 1.8839 (8)Å to 1.8910 (10)Å while the axial bond lengths to the water and acetate moieties are slightly longer at 1.9454 (8)Å and 1.8995 (8)Å respectively. The only slightly distorted nature of the coordination sphere about the Co is emphasized by the fact that the cis angles vary from 78.40 (4)° to 94.18 (4)° while the trans angles range from 173.73 (3)° to 178.40 (4)°.

There is extensive O—H···O intra- and intermolecular hydrogen bonding between the coordinated water and acetate moieties and the methanol solvate molecules (Fig. 2). In addition there are weak C—H···O intermolecular interactions. These link the structure into a three-dimensional array.

Experimental

The synthesis of the ligand 3-methoxyethylenediaminebissalicylaldimine was accomplished by the reaction of the solution of (2 g, 33.3 mmol) of ethylenediamine in 10 ml methanol which was added to the solution of o-vanillin in 40 ml methanol dropwise using a glass pipette. The mixture was refluxed for 24 h. After solvent evaporation under reduced pressure yellow solids were obtained.

The complex was synthesized by mixing a solution of (0.25 g, 1 mmol) of Co(CH₃COO)₂^.4H₂O in 5 ml me thanol with a solution of (0.33 g, 1 mmol) 3-methoxyethylenediaminebissalicylaldimine in 3 ml of dichloromethene. The mixture was stirred for 1 h at room temperature, filtered and layered with diethyl ether for crystallization. Crystals suitable for single-crystal X-ray diffraction were obtained by slow evaporation.