Chlorido{5,5′-dimeth­oxy-2,2′-[1,2-phenyl­enebis(nitrilo­methyl­idyne)]diphenolato-κ4 O,N,N′,O′}manganese(III)

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

doi:10.1107/S1600536808009835

. 2008 Apr 16;64(Pt 5):m670–m671. doi: 10.1107/S1600536808009835

Chlorido{5,5′-dimethoxy-2,2′-[1,2-phenylenebis(nitrilomethylidyne)]diphenolato-κ⁴ O,N,N′,O′}manganese(III)

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

PMCID: PMC2961208 PMID: 21202211

Abstract

In the title complex, [Mn(C₂₂H₁₈N₂O₄)Cl], the Mn^III centre is in a distorted square-pyramidal configuration, with the basal plane formed by the N₂O₂ donors of the tetradentate Schiff base dianion; the two phenolate O atoms and the two imine N atoms are each mutually cis. The chloride ion occupies the apical position. The dihedral angle between the two outer phenolate rings of the tetradentate Schiff base ligand is 16.44 (9)°. The central benzene ring makes dihedral angles of 10.64 (9) and 25.17 (10)° with the two outer phenolate rings. In the crystal structure, weak C—H⋯O and C—H⋯Cl interactions link the molecules into wave-like face-to-face double layers along the c direction. A π–π interaction involving the two outer phenolate rings is observed, the centroid–centroid distance being 3.743 (11) Å.

Related literature

For values of bond lengths, see: Allen et al. (1987 ▶). For details of ring conformations, see: Cremer & Pople (1975 ▶). For related structures, see, for example: Eltayeb et al. (2008a ▶,b ▶); Habibi et al. (2007 ▶); Mitra et al. (2006 ▶). For the background to applications of manganese complexes, see, for example: Dixit & Srinivasan (1988 ▶); Glatzel et al. (2004 ▶); Lu et al. (2006 ▶).

Experimental

Crystal data

[Mn(C₂₂H₁₈N₂O₄)Cl]
M _r = 464.77
Orthorhombic,
a = 13.7282 (2) Å
b = 15.0250 (2) Å
c = 19.2094 (3) Å
V = 3962.25 (10) Å³
Z = 8
Mo Kα radiation
μ = 0.83 mm⁻¹
T = 296 (2) K
0.44 × 0.42 × 0.11 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.708, T _max = 0.915
28689 measured reflections
5780 independent reflections
4072 reflections with I > 2σ(I)
R _int = 0.032

Refinement

R[F ² > 2σ(F ²)] = 0.038
wR(F ²) = 0.095
S = 1.05
5780 reflections
273 parameters
H-atom parameters constrained
Δρ_max = 0.30 e Å⁻³
Δρ_min = −0.34 e Å⁻³

Data collection: APEX2 (Bruker, 2005 ▶); cell refinement: APEX2; data reduction: SAINT (Bruker, 2005 ▶); 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, 2003 ▶).

Supplementary Material

Crystal structure: contains datablocks global, I. DOI: 10.1107/S1600536808009835/is2286sup1.cif

e-64-0m670-sup1.cif^{(23.7KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808009835/is2286Isup2.hkl

e-64-0m670-Isup2.hkl^{(283.1KB, 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
C7—H7A⋯Cl1ⁱ	0.93	2.81	3.7156 (19)	165
C21—H21A⋯O2ⁱⁱ	0.96	2.44	3.321 (2)	152

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

Acknowledgments

The authors thank the Malaysian Government, Ministry of Science, Technology and Innovation (MOSTI), and the Universiti Sains Malaysia for the E-Science Fund, RU research grant (Nos. PKIMIA/613308, PKIMIA/815002, 203/PKIMIA/671083) and facilities. The International University of Africa (Sudan) is acknowledged for providing study leave to NEE. The authors also thank Universiti Sains Malaysia for the Fundamental Research Grant Scheme (FRGS) (grant No. 203/PFIZIK/671064).

supplementary crystallographic information

Comment

There has been considerable interest in Schiff base ligand containing oxygen and imine nitrogen atoms and their metal complexes due to their variety of applications such as manganese complexes with Schiff base ligands which have diverse range of applications in chemistry, biology, physics and advanced materials and are used in catalysis (Dixit & Srinivasan, 1988), as models for the oxygen-evolving complex of photosystem II (Glatzel et al., 2004), and as single-molecule magnets (Lu et al., 2006). We have previously reported the crystal structures of five coordinate Mn^III complexes with closely-related N₂O₂ donor Schiff base ligands, chlorido{6,6'-dimethyl-2,2'-[1,2-phenylenebis(nitrilomethylidene)]diphenolato- κ⁴O,N,N',O'}manganese(III) monohydrate (Eltayeb et al., 2008a) and chlorido{5,5'-dimethyl-2,2'-[1,2- phenylenebis(nitrilomethylidene)]diphenolato- κ⁴O,N,N',O'}manganese(III) (Eltayeb et al., 2008b). We report here the synthesis and structure of (I), Fig. 1, another five-coordinate Mn^III complex of a closely-related ligand.

In (I), the Mn^III complex shows a slightly distorted square-pyramidal geometry involving N1, N2, O1 and O2 atoms of the tetradentate Schiff base ligand as the basal plane. The two phenolic oxygen atoms and two imine nitrogen atoms are located in cis positions. The apical position is filled by the Cl^- ion. The Mn—O distances [Mn1—O1 = 1.8623 (12) Å, Mn1—O2 = 1.9067 (11) Å] and Mn—N distances [Mn1—N1 = 1.9859 (14) Å, Mn1—N2 = 1.9876 (14) Å] are in the same ranges as those observed in other related Mn^III complexes of N₂O₂ Schiff base ligands (Eltayeb et al. , 2008a,b; Habibi et al., 2007; Mitra et al., 2006). Other bond lengths and angles observed in the structure are also normal (Allen et al., 1987). The basal bond angles are close to 90° [O1–Mn1–O2 = 92.82 (5)°, O1–Mn1–N1 = 93.06 (5)°, O2–Mn1–N2 = 90.13 (6)°] excepting for the N–Mn–N angle is smaller than 90 ° [N1–Mn1–N2 = 81.68 (6)°]. The distorted square-pyramidal geometry of (I) can be reflected by the bond angles between the Cl^- ion and the atoms in the basal plane which are in the range 96.89 (4) to 97.16 (4)°. All these angle are close to the correspondence angles in the closely related structures (Eltayeb et al., 2008a,b). Coordination of the N₂O₂ chelate ligand to the Mn^III ion results in the formation of an essentially planar five-membered ring (Mn1/N1/N2/C8/C13) and two six-membered rings; the Mn1/O1/N1/C1/C6/C7 ring is almost planar with the greatest deviation being -0.041 (1) Å for atom O1 whereas the Mn1/O2/N2/C14/C15/C20 ring adopts an envelope conformation with atom O2 displaced from the Mn1/N2/C14/C15/C20 plane by -0.276 (1) Å and with Cremer & Pople (1975) puckering parameters Q = 0.4418 (12)°, θ = 60.1 (2)° and φ = 20.2 (2)°. The dihedral angle between the two outer phenolate rings [C1–C6 and C15–C20] of the Schiff base ligand is 16.44 (9)°. The central benzene ring (C8–C13) makes dihedral angles of 10.64 (9) and 25.17 (10)° with the two outer phenolate rings. In addition one methoxy group is almost planarly attached to the (C15–C20) phenolate ring which can be indicated by the torsion angle C22–O4–C18–C19 = -3.4 (3)° whereas another methoxy group is slightly deviated from the mean plane of the C15–C20 phenolate ring, as shown by the torsion angle C21–O3–C3–C4 = 9.4 (3)°. The dihedral angles between the phenolate and benzene rings found in (I) are smaller than the corresponding angles found in a closely related structure (Eltayeb et al., 2008b), showing that the Schiff base ligand in (I) is more flat due to the different substituents in the phenolate rings of the Schiff base ligand which are two methoxy groups in (I) but are two methyl groups in the same positions in (Eltayeb et al., 2008b).

In the crystal packing (Fig. 2), weak C—H···O and C—H···Cl interactions (Table 1) link the molecules into wave like face-to-face double layers along the c direction. The crystal is stabilized by these weak C—H···O and C—H···Cl interactions. A π-π interaction was also observed in the crystal with the Cg₁···Cg₂ⁱ distance of 3.7430 (11) Å [Cg₁ and Cg₂ are the centroids of the C1–C6 and C15–C20 phenolate rings, respectively; symmetry code: (i) 1-x, -y, 1-z].

Experimental

The title compound was synthesized by adding 2-hydroxy-4-methoxybenzaldehyde (0.610 g, 4 mmol) to a solution of o-phenylenediamine (0.216 g, 2 mmol) in ethanol 95% (30 ml). The mixture was refluxed with stirring for half an hour. Manganese chloride tetrahydrate (0.394 g, 2 mmol) in ethanol (10 ml) was then added, followed by triethylamine (0.5 ml, 3.6 mmol). The mixture was refluxed at room temperature for three hours. A brown precipitate was obtained, washed with about 5 ml ethanol, dried, and then washed with copious quantities of diethylether. Brown single crystals of the title compound suitable for x-ray structure determination were recrystallized from methanol by slow evaporation of the solvent at room temperature after two weeks.