(2-{[2-(1H-Benzimidazol-2-yl-κN 3)phen­yl]imino­methyl-κN}-5-methyl­phenolato-κO)chloridozinc(II)

Naser Eltaher Eltayeb; Siang Guan Teoh; Suchada Chantrapromma; Hoong-Kun Fun

doi:10.1107/S1600536811030170

. 2011 Aug 2;67(Pt 9):m1182–m1183. doi: 10.1107/S1600536811030170

(2-{[2-(1H-Benzimidazol-2-yl-κN ³)phenyl]iminomethyl-κN}-5-methylphenolato-κO)chloridozinc(II)

Naser Eltaher Eltayeb ^a,^b, Siang Guan Teoh ^a, Suchada Chantrapromma ^c,^‡, Hoong-Kun Fun ^d,^*,^§

PMCID: PMC3200787 PMID: 22065469

Abstract

In the title mononuclear complex, [Zn(C₂₁H₁₆N₃O)Cl], the Zn^II ion is coordinated in a distorted tetrahedral geometry by two benzimidazole N atoms and one phenolate O atom from the tridentate Schiff base ligand and a chloride ligand. The benzimidazole ring system forms dihedral angles of 26.68 (9) and 56.16 (9)° with the adjacent benzene ring and the methylphenolate group benzene ring, respectively. In the crystal, molecules are linked by N—H⋯Cl hydrogen bonds into chains along [100]. Furthermore, weak C—H⋯O and C—H⋯π interactions, in addition to π–π interactions with centroid–centroid distances in the range 3.5826 (13)–3.9681 (13) Å, are also observed.

Related literature

For standard bond-length data, see: Allen et al. (1987 ▶). For background to benzimidazoles and their applications, see: Chassaing et al. (2008 ▶); Kucukbay et al. (2003 ▶); Podunavac-Kuzmanovic & Cvetkovic (2010 ▶); Podunavac-Kuzmanovic et al. (1999 ▶); Podunavac-Kuzmanovic & Markov (2006 ▶); Xue et al. (2011 ▶). For related structures, see: Eltayeb et al. (2007 ▶, 2009 ▶); Eltayeb, Teoh, Chantrapromma & Fun (2011 ▶); Eltayeb, Teoh, Yeap & Fun (2011 ▶); Maldonado-Rogado et al. (2007 ▶); Tong & Ye (2004 ▶). For the stability of the temperature controller used in the data collection, see: Cosier & Glazer, (1986 ▶).

Experimental

Crystal data

[Zn(C₂₁H₁₆N₃O)Cl]
M _r = 427.21
Monoclinic,
a = 8.6338 (1) Å
b = 19.4952 (2) Å
c = 10.9687 (1) Å
β = 99.675 (1)°
V = 1819.97 (3) Å³
Z = 4
Mo Kα radiation
μ = 1.51 mm⁻¹
T = 100 K
0.26 × 0.18 × 0.09 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.694, T _max = 0.878
22729 measured reflections
5678 independent reflections
3773 reflections with I > 2σ(I)
R _int = 0.042

Refinement

R[F ² > 2σ(F ²)] = 0.042
wR(F ²) = 0.088
S = 1.03
5678 reflections
249 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.64 e Å⁻³
Δρ_min = −0.39 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: SAINT (Bruker, 2005 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXTL (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL and PLATON (Spek, 2009 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536811030170/lh6598sup1.cif

e-67-m1182-sup1.cif^{(22.3KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811030170/lh6598Isup2.hkl

e-67-m1182-Isup2.hkl^{(278KB, hkl)}

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

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

Cg1 and Cg2 are the centroids of the C15–C20 and C8–C13 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N2—H1N1⋯Cl1ⁱ	0.75 (3)	2.53 (3)	3.2352 (19)	157 (2)
C2—H2A⋯O1ⁱⁱ	0.93	2.59	3.425 (3)	149
C12—H12A⋯Cg1ⁱⁱⁱ	0.93	2.96	3.762 (3)	145
C21—H21C⋯Cg2^iv	0.96	2.92	3.741 (3)	144

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

Acknowledgments

The authors thank the Malaysian government and Universiti Sains Malaysia for the Research University Grant No. 1001/PKIMIA/815067. NEE thanks Universiti Sains Malaysia for a postdoctoral fellowship and the International University of Africa (Sudan) for providing study leave. The authors also thank the Universiti Sains Malaysia for the Research University Grant No. 1001/PFIZIK/811160.

supplementary crystallographic information

Comment

Benzimidazole compounds and their complexes have been found to show diverse biological activity (Chassaing et al., 2008; Kucukbay et al., 2003; Podunavac-Kuzmanovic & Cvetkovic, 2010; Podunavac-Kuzmanovic et al., 1999; Podunavac-Kuzmanovic & Markov, 2006) including inhibition against enteroviruses (Xue et al., 2011). Our ongoing structural studies involves benzimidazoles (Eltayeb et al., 2007, 2009; Eltayeb, Teoh, Yeap & Fun, 2011) and their complexes (Eltayeb, Teoh, Chantrapromma & Fun, 2011). In the preparation of the title complex (I), 2-(2-aminophenyl)-1H-benzimidazole undergoes a condensation reaction with 2-hydroxy-4-methylbenzaldehyde to give a Schiff base ligand and forming the zinc(II) complex.

Complex (I) is a mononuclear zinc(II) complex (Fig. 1) in which the environment around the Zn^II ion is a distorted tetrahedral geometry and the Zn^II ion is four-coordinated by the two benzimidazole N atoms, one phenolate O atom and a Cl ligand. In the complex, the Schiff base ligand acts as a tridentate ligand. The bond angles around the central metal zinc(II) show large deviations from ideal tetrahedral geometry [O1-Zn1-Cl1 = 115.14 (5)°, N1-Zn1-Cl1 = 111.84 (5)°, N3-Zn1-Cl1 = 120.39 (6)°; and the bite angles N1–Zn1-N3 = 90.39 (7)° and O1-Zn1-N3 = 95.00 (7)°]. The Zn-N [1.9954 (17) and 2.2092 (18) Å], Zn-O [1.9137 (15) Å] and Zn-Cl [2.2249 (7) Å] bond lengths are comparable to those of similar Zn(II) benzimidazole complexes (Eltayeb, Teoh, Chantrapromma & Fun, 2011; Maldonado-Rogado et al., 2007; Tong & Ye, 2004). The benzimidazole ring system (C1–C7/N1–N2) is planar with an r.m.s. deviation of 0.0074 (2) Å and the largest deviation of 0.029 (2) Å for atom N1. The benzimidazole ring system forms dihedral angles of 26.68 (9) and 56.16 (9)° with the C8–C13 and C15–C20 rings, respectively. The dihedral angle between the C8–C13 and C15–C20 benzene rings is 35.26 (11)°. The bond lengths of ligand are within normal ranges (Allen et al., 1987).

In the crystal structure of (I) as shown Fig. 2, the molecules are linked through N—H···Cl hydrogen bonds (Table 1) into chains along the a axis. C—H···O and C—H···π weak interactions (Table 1) are also present. π–π interactions were also observed with centroid···centroid distances: Cg1···Cg2^v = 3.6134 (13) Å; Cg1···Cg3^vi = 3.9681 (13) Å and Cg2···Cg2^v = 3.5826 (13) Å; Cg1, Cg2 and Cg3 are the centroids of the C1/C6–C7/N1–N2, C1–C6 and C8–C13 rings, respectively [symmetry codes: (v) 2-x, -x, 1-z; (vi) 2-x, -y, 2-z].

Experimental

The title compound was synthesized by adding 2-hydroxy-4-methylbenzaldehyde (0.136 g, 1.0 mmol) to a solution of 2-(2-aminophenyl)-1H-benzimidazole (0.209 g, 1.0 mmol) in ethanol (30 mL). The color of the resulting solution was pale-yellow. Upon adding zinc chloride (0.136 g, 1.0 mmol), the color of the solution turned golden-yellow. The mixture was refluxed with stirring for 3 hrs. Yellow block-shaped single crystals of the title compound suitable for x-ray structure determination were obtained from ethanol by slow evaporation at room temperature after several days.