Bis{2-bromo-4-chloro-6-[(E)-(2,6-di­methyl­phen­yl)imino­meth­yl]phenolato-κ2 N,O}cobalt(II)

Gang Zhu; Bao-Juan Jiao

doi:10.1107/S1600536813003747

. 2013 Feb 20;69(Pt 3):m156. doi: 10.1107/S1600536813003747

Bis{2-bromo-4-chloro-6-[(E)-(2,6-dimethylphenyl)iminomethyl]phenolato-κ² N,O}cobalt(II)

Gang Zhu ^a,^*, Bao-Juan Jiao ^a

PMCID: PMC3588491 PMID: 23476501

Abstract

In the title complex, [Co(C₁₅H₁₂BrClNO)₂], the Co^II ion is coordinated by two N,O-bidentate 2-bromo-4-chloro-6-[(E)-(2,6-dimethylphenyl)iminomethyl]phenolate ligands, generating a squashed CoN₂O₂ tetrahedral coordination geometry. The dihedral angles between the aromatic rings in the ligands are 82.60 (14) and 71.79 (14)°. The complex has approximate local noncrystallographic twofold symmetry. In the crystal, weak aromatic π–π stacking is observed [centroid–centroid separation = 3.6434 (18) Å].

Related literature

For background to Schiff bases, see: Billson et al. (2000 ▶); Carlton et al. (1995 ▶); Feng et al. (2008 ▶); Liu et al. (2009 ▶).

Experimental

Crystal data

[Co(C₁₅H₁₂BrClNO)₂]
M _r = 734.16
Monoclinic,
a = 11.608 (2) Å
b = 24.157 (4) Å
c = 11.354 (2) Å
β = 114.380 (2)°
V = 2899.8 (9) Å³
Z = 4
Mo Kα radiation
μ = 3.56 mm⁻¹
T = 153 K
0.49 × 0.27 × 0.12 mm

Data collection

Rigaku AFC10/Saturn724+ diffractometer
Absorption correction: multi-scan (CrystalClear; Rigaku, 2008 ▶) T _min = 0.274, T _max = 0.683
32947 measured reflections
7718 independent reflections
6813 reflections with I > 2σ(I)
R _int = 0.047

Refinement

R[F ² > 2σ(F ²)] = 0.044
wR(F ²) = 0.119
S = 1.00
7718 reflections
356 parameters
H-atom parameters constrained
Δρ_max = 0.54 e Å⁻³
Δρ_min = −0.63 e Å⁻³

Data collection: CrystalClear (Rigaku, 2008 ▶); cell refinement: CrystalClear; data reduction: CrystalClear; 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

Click here for additional data file.^{(25.6KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536813003747/hb7032sup1.cif

e-69-0m156-sup1.cif^{(25.6KB, cif)}

Click here for additional data file.^{(377.6KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813003747/hb7032Isup2.hkl

e-69-0m156-Isup2.hkl^{(377.6KB, hkl)}

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

Table 1. Selected bond lengths (Å).

Co1—O2	1.9006 (18)
Co1—O1	1.9144 (18)
Co1—N2	1.983 (2)
Co1—N1	2.000 (2)

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Acknowledgments

The authors are grateful for financial support from the Science & Technology Project Foundation of Xi’an (grant No. CX12189WL19), the Special Foundation of the Education Department of Shaanxi Province (grant No. 11 J K0577) and the Key Disciplinary Areas of Analytical Chemistry of Shaanxi Province, People’s Republic of China.

supplementary crystallographic information

Comment

Schiff bases possess strong coordination function and may act as bi-, tri-, and poly-dentate ligands to yield plenty of mono-, bi-, tri-, and poly-nuclear Schiff-base complexes, so the design of metal-organic coordination polymers is of current interest in the fields of supramolecular chemistry and crystal engineering because of their potential applications as functional materials (Feng, et al., 2008; Liu, et al., 2009). Meanwhile, Schiff bases and their metal complexes exhibit biological activity as antibiotics, antiviral and antitumour agents because of their specific structures (Billson, et al., 2000; Carlton, et al., 1995). Thus, it is quite important to have a good understanding of the structure of such metal complexes.

In this paper, we report synthesis and crystal structure of a new cobalt(II) complex, bis[2-((E)-(2,6-dimethylphenylimino) methyl)-6-bromo-4-chlorophenol]cobalt(II). The structure of the complex had been established accurately from the X-ray single-crystal diffraction study. The Co(II) ion in the monomeric unit seems to reside in a distorted tetrahedral environment and bonds to two oxygen atoms and two nitrogen atoms from two Schiff bases.

A thermal ellipsoid drawing and crystal packing structure of the title complex are shown in Figure 1 and Figuer 2. The Co(C₁₅H₁₂BrClNO)₂ motif is asymmetrical with Co—N and Co—O bonds, the corresponding distances are d(Co—N1) = 2.000 (2), d(Co—O1) = 1.9144 (18), d(Co—N2) = 1.983 (2), d(Co—O2) = 1.9006 (2)Å. The cobalt atom is in a distorted tetrahedral environmente, where the values of trans bond angles also indicate the coordination environment with O(2)—Co(1)—N(1), O(2)—Co(1)—N(2) and O(2)—Co(1)—O(1) angles of 116.97 (9), 94.94 (8) and 113.77 (8) °, respectively.

In the crystal structure of the complex the atoms of the phenyl ring plane A (C(1) C(2) C(3) C(4) C(5) C(6)) and the chelate ring formed by the same ligand plane B ((O(1)/Co(1)/N(1)/C(7)/C(1)/C(6)) are nearly coplanar with a dihedral angle of 8.09 (10) °. Because of the conjugation effects through the imino double bond N(1)═C(7), the phenyl ring A and the phenyl ring C (C(8) C(9) C(10) C(11) C(12) C(13)) joined by the N(1)═C(7) bond, are non-coplanar (with the dihedral angle 74.55 (7) °, decreasing the steric effects between the two rings. If the two chelate planes, planes B and D((N(2)/Co(1)/O(2)/C(17)/C(16)/C(22)), are compared the dihedral angle is 87.19 (6) °, naerly perpendicular.

Experimental

3-Bromo-5-chlorosalicylaldehyde (0.2 mmol, 47.2 mg) and 2,6-Dimethylaniline (0.2 mmol, 24.2 mg) were dissolved in EtOH (15 mL). The mixture was stirred for 30 min at room temperature to give an orange solution. To the resulting orange solution was added Co(CH₃COO)₂ (0.1 mmol, 17.7 mg). Then a clear brown solution was obtained. The title complex were obtained from the solution after 4 d in the form of red chunks. The product was filtered, washed with EtOH, and dried over anhydrous CaCl₂in vacuo overnight. Yield: 70%. Anal. Calcd. (%) for C₃₀H₂₄CoN₂O₂Cl₂Br₂: C, 49.08; H, 3.29; N, 3.82. Found (%): C, 49.13; H, 3.43; N, 3.70.