Chlorido{5,5′-dimethyl-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/S1600536808007459

. 2008 Mar 29;64(Pt 4):m570–m571. doi: 10.1107/S1600536808007459

Chlorido{5,5′-dimethyl-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: PMC2960927 PMID: 21202022

Abstract

In the title complex, [Mn(C₂₂H₁₈N₂O₂)Cl], the Mn^III center is in a distorted square-pyramidal configuration; the basal plane is formed by the N₂O₂ donors of the tetradentate Schiff base dianion, with the two phenol O atoms and two imine N atoms each mutually cis. The chloride ion occupies the apical coordination site. The dihedral angle between the two outer phenolate rings of the tetradentate ligand is 18.24 (9)°. The central benzene ring makes dihedral angles of 13.71 (8) and 30.50 (8)° with the two outer phenolate rings. In the crystal structure, weak C—H⋯Cl interactions link the molecules into screw helices along the b direction. These helices are further connected by weak C—H⋯O interactions into a three-dimensional network. The crystal structure is further stabilized by C—H⋯π interactions involving the central benzene ring.

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. (2008 ▶); Habibi et al. (2007 ▶); Mitra et al. (2006 ▶). For background to applications of manganese complexes, see, for example: Dixit & Srinivasan (1988 ▶); Glatzel et al. (2004 ▶); Lu et al. (2006 ▶); Stallings et al. (1985 ▶).

Experimental

Crystal data

[Mn(C₂₂H₁₈N₂O₂)Cl]
M _r = 432.77
Monoclinic,
a = 20.9593 (5) Å
b = 13.5897 (3) Å
c = 14.9316 (3) Å
β = 119.641 (1)°
V = 3696.43 (14) Å³
Z = 8
Mo Kα radiation
μ = 0.88 mm⁻¹
T = 100.0 (1) K
0.56 × 0.20 × 0.19 mm

Data collection

Bruker SMART APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.639, T _max = 0.852
35769 measured reflections
8109 independent reflections
5992 reflections with I > 2σ(I)
R _int = 0.048

Refinement

R[F ² > 2σ(F ²)] = 0.045
wR(F ²) = 0.126
S = 1.07
8109 reflections
255 parameters
H-atom parameters constrained
Δρ_max = 0.75 e Å⁻³
Δρ_min = −0.69 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/S1600536808007459/sj2474sup1.cif

e-64-0m570-sup1.cif^{(23.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808007459/sj2474Isup2.hkl

e-64-0m570-Isup2.hkl^{(396.8KB, 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
C5—H5A⋯Cl1ⁱ	0.93	2.77	3.6508 (16)	158
C7—H7A⋯Cl1ⁱ	0.93	2.81	3.6933 (15)	158
C11—H11A⋯O1ⁱⁱ	0.93	2.58	3.423 (2)	151
C4—H4A⋯Cg1ⁱⁱⁱ	0.93	2.83	3.5443 (19)	135

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) . Cg1 is the centroid of the C8–C13 benzene ring.

Acknowledgments

The authors thank the Malaysian Government, Ministry of Science, Technology and Innovation (MOSTI), and Universiti Sains Malaysia for the E-Science Fund research grant (PKIMIA/613308) 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

We have been interested in syntheses of Schiff base ligands containing oxygen and imine nitrogen atoms and their metal complexes due to their variety of applications. Manganese complexes with Schiff base ligands have numerous applications in chemistry, biology, physics and advanced materials and are used in catalysis (Dixit and 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). They also serve as models for the active sites of manganese-containing metal enzymes (Stallings et al., 1985). Recently, we reported the crystal structure of a five coordinate Mn^III complex with a similar N₂O₂ donor Schiff base ligand, chlorido{6,6'-dimethyl-2,2'-[1,2-phenylenebis(nitrilomethylidene)]diphenolato- κ⁴O,N,N',O'}manganese(III) monohydrate (Eltayeb et al., 2008). We report here the structure of (I), Fig. 1, a Mn^III complex of a closely-related ligand.

In (I) the Mn^III center is in a slightly distorted square-pyramidal geometry coordinating through N1, N2, O1 and O2 atoms of the tetradentate Schiff base ligand in the basal plane with the two phenolic O atoms and two imine N atoms in mutually cis positions. The apical position is coordinated by the Cl^- ion. The Mn—O distances [Mn1—O1 = 1.8698 (12)Å, Mn1—O2 = 1.8983 (10)Å] and Mn—N distances [Mn1—N1 = 1.9923 (12)Å, Mn1—N2 = 1.9875 (12)Å] are in the same ranges of those observed in other related Mn^III complexes of N₂O₂ Schiff base ligands (Eltayeb et al., 2008; 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 O1–Mn1–O2 of 92.61 (4)°, O–Mn–N [O1–Mn1–N1 = 93.07 (5)°, O2–Mn1–N2 = 89.21 (5)°] are close to 90° whereas the N–Mn–N is smaller than 90° [N1–Mn1–N2 = 82.10 (5)°]. The bond angles between the Cl^- ion and the atoms in the basal plane are in the range 93.14 (4) to 99.97 (4)°, indicating a distorted square-pyramidal geometry. Coordination of the the N₂O₂ chelate ligand to the Mn^III ion results in the formation of an essentialy 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 0.059 (1)Å for atom O2 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 0.298 (1)Å and with Cremer & Pople (1975) puckering parameters Q = 0.483 (1)°, θ = 61.0 (1)° and φ = 18.8 (2)°. These parameters are larger in values than those observed in the closely-related structure (Eltayeb et al., 2008). The dihedral angle between the two outer phenolate rings [C1–C6 and C15–C20] of the Schiff base ligand is 18.24 (9)°. The central benzene ring (C8–C13) makes dihedral angles of 13.71 (8)° and 30.50 (8)° with the two outer phenolate rings. These dihedral angles are all wider than the corresponding angles found in a closely related structure (Eltayeb et al., 2008) due to the different locations of the two methyl substituents on the phenolate rings of the Schiff base ligand.

In the crystal packing (Fig. 2), weak C—H···Cl interactions (Table 1) link the molecules into screw helices along the b direction. These helices are further connected by weak C—H···O interactions into a three-dimensional network. The crystal is further stabilized by weak C—H···π interactions (Table 1); Cg₁ is the centroid of the C8–C13 benzene ring.

Experimental

The title compound was synthesized by adding 2-hydroxy-4-methylbenzaldehyde (0.546 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 ethanol/methanol (2:1 v/v) by slow evaporation of the solvent at room temperature over two months.