The cocrystal aqua­chlorido{6,6′-di-tert-butyl-2,2′-[1,2-phenyl­enebis(nitrilo­methyl­idyne)]diphenolato-κ4 O,N,N′,O′}­manganese(III)–chlorido{6,6′-di-tert-butyl-2,2′-[1,2-phenyl­enebis(nitrilo­methyl­idyne)]diphenolato-κ4 O,N,N′,O′}(methanol-κO)manganese(III) (1/1)

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

doi:10.1107/S1600536808006818

. 2008 Apr 4;64(Pt 5):m626–m627. doi: 10.1107/S1600536808006818

The cocrystal aquachlorido{6,6′-di-tert-butyl-2,2′-[1,2-phenylenebis(nitrilomethylidyne)]diphenolato-κ⁴ O,N,N′,O′}manganese(III)–chlorido{6,6′-di-tert-butyl-2,2′-[1,2-phenylenebis(nitrilomethylidyne)]diphenolato-κ⁴ O,N,N′,O′}(methanol-κO)manganese(III) (1/1)

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

PMCID: PMC2961111 PMID: 21202181

Abstract

The asymmetric unit of the title complex, [Mn(C₂₈H₃₀N₂O₂)Cl(H₂O)][Mn(C₂₈H₃₀N₂O₂)Cl(CH₃OH)], contains two discrete Mn^III complexes of a Schiff base ligand, with an N₂O₂ donor set. Both Mn^III centers are in a distorted octahedral geometry with the N₂O₂ donor atoms of the tetradentate Schiff base dianion in the equatorial plane. The axial positions in the coordination environment of one Mn^III complex are occupied by a chloride ion and a water molecule, but a methanol molecule replaces the water molecule in the other complex. The coordinated water molecule takes part in an O—H⋯Cl hydrogen bond between the two Mn^III complexes. In the crystal structure, O—H⋯Cl hydrogen bonds link the molecules into infinite one-dimensional chains along the [100] direction. The crystal structure is stabilized by O—H⋯Cl hydrogen bonds together with weak C—H⋯O and C—H⋯Cl interactions. A C—H⋯π interaction is also observed in the crystal structure.

Related literature

For bond-length data, see: Allen et al. (1987 ▶). For related structures, see for example: Eltayeb et al. (2007 ▶, 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(C₂₈H₃₀N₂O₂)Cl(H₂O)][Mn(C₂₈H₃₀N₂O₂)Cl(CH₄O)]
M _r = 1083.92
Triclinic,
a = 13.1080 (3) Å
b = 13.8794 (3) Å
c = 14.6085 (3) Å
α = 95.177 (1)°
β = 99.996 (1)°
γ = 95.639 (1)°
V = 2589.08 (10) Å³
Z = 2
Mo Kα radiation
μ = 0.65 mm⁻¹
T = 100.0 (1) K
0.38 × 0.33 × 0.03 mm

Data collection

Bruker SMART APEX2 CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2005 ▶) T _min = 0.791, T _max = 0.981
37620 measured reflections
10108 independent reflections
6163 reflections with I > 2σ(I)
R _int = 0.076

Refinement

R[F ² > 2σ(F ²)] = 0.057
wR(F ²) = 0.147
S = 1.03
10108 reflections
653 parameters
H-atom parameters constrained
Δρ_max = 0.56 e Å⁻³
Δρ_min = −0.52 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/S1600536808006818/sj2472sup1.cif

e-64-0m626-sup1.cif^{(45.6KB, cif)}

Structure factors: contains datablocks I. DOI: 10.1107/S1600536808006818/sj2472Isup2.hkl

e-64-0m626-Isup2.hkl^{(494.3KB, 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
O1WA—H2WA⋯Cl1B	0.85	2.28	3.113 (3)	167
O3B—H1O3⋯Cl1Aⁱ	1.00	2.06	3.026 (3)	163
C5A—H5AA⋯O1WAⁱⁱ	0.93	2.55	3.463 (5)	169
C4B—H4BA⋯Cl1Aⁱⁱ	0.93	2.79	3.528 (4)	137
C12B—H12B⋯Cl1Aⁱⁱⁱ	0.93	2.73	3.646 (4)	170
C23A—H23C⋯O1A	0.96	2.34	2.984 (6)	124
C23B—H23E⋯O1B	0.96	2.35	2.983 (5)	123
C24A—H24C⋯O1A	0.96	2.34	2.975 (5)	123
C24B—H24E⋯O1B	0.96	2.36	3.010 (5)	124
C26A—H26A⋯O2A	0.96	2.45	3.041 (5)	119
C26B—H26E⋯O2B	0.96	2.35	2.998 (5)	124
C28A—H28A⋯O2A	0.96	2.34	2.977 (5)	124
C28B—H28F⋯O2B	0.96	2.34	2.968 (5)	122
C14B—H14B⋯Cg1^iv	0.93	3.23	3.690 (4)	113

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Symmetry codes: (i) Inline graphic ; (ii) ; (iii) ; (iv) . Cg1 is the centroid of the C8B–C13B 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

Manganese complexes with Schiff base ligands have been of interest due to the variety of their applications in coordination chemistry, physics, catalysis and biological replication. They have been used as models for the oxygen-evolving complex of photosystem II (Glatzel et al., 2004), in catalysis (Dixit & Srinivasan, 1988), as single-molecule magnets (Lu et al., 2006) and serve as models for the active sites of manganese-containing metal enzymes (Stallings et al., 1985). We have previously reported the crystal structure of manganese complexes with Schiff base ligands containing oxygen and imine nitrogen atoms (Eltayeb et al., 2007; 2008). In this paper, we report the crystal structure of a Mn(III) complex of the closely related ligand {6,6'-di-tert-butyl-2,2'-[1,2-phenylenebis(nitrilomethylidene)]diphenolate.

The asymmetric unit of the title complex molecule (Fig. 1) contains two Mn^III complexes (A and B) with the same Schiff base ligand. Coordination spheres around Mn^III in both A and B are slightly distorted octahedra, with the coordination plane of each Mn^III formed by the N₂O₂ donor atoms of the Schiff base. The axial positions in A are occupied by a Cl^- ion and a water molecule whereas in B, these positions are occupied by a Cl^- ion and a CH₃OH molecule. The in-plane Mn—O distances are in the range 1.863 (2)–1.882 (2) Å with Mn—N distances 1.978 (3)–1.997 (3) Å, which fall in the range observed for six other Mn^III coordination complexes of Schiff base ligands (Eltayeb et al., 2007; 2008; Habibi et al., 2007; Mitra et al., 2006). The elongation of the Mn—O and Mn—Cl axial bonds [2.402 (3) and 2.5420 (12) Å in A and 2.293 (3) and 2.5416 (11) Å in B] clearly indicate the usual Jahn Teller distortion of the Mn^III oxidation state as has been found previously (Eltayeb et al., 2007; 2008; Habibi et al., 2007; Mitra et al., 2006). The basal bond angles O–Mn–O and O–Mn–N are close to 90° whereas the N–Mn–N angles are less than 90° [N1A–Mn1A–N2A = 82.19 (12)° and N1B–Mn1B–N2B = 81.67 (12)°]. The axial bond angle Cl–Mn–O is also less than the ideal value of 180° [170.55 (7)° in A and 171.74 (8)° in B]. Other bond lengths and angles observed in the structure are also normal (Allen et al., 1987). The coordinated water molecule of molecule A forms an O—H···Cl hydrogen bond with the coordinated Cl^- ion of molecule B (Fig. 1). The dihedral angles between the two outer phenolate rings [(C1–C6) and C15–C20) of the tetradentate Schiff base ligand is 22.21 (19)° in A and 18.81 (19)° in B°. The central benzene ring (C8–C13) makes dihedral angles of 13.43 (19)° and 8.79 (19)° with the two outer phenolate rings in A [10.94° and 10.37 (19)° in B].

In the crystal structure (Fig. 2), O—H···Cl hydrogen bonds [O1WA—H2WA···Cl1B; symmetry code x, y, z and O3B—H1O3—Cl1A; symmetry code 1 + x, y, z) (Table 1)] link the Mn^III complex molecules into infinite one-dimensional chains along the [1 0 0] direction. The crystal is stabilized by these O—H···Cl hydrogen bonds, together with weak C—H···O and C—H···Cl interactions and further stabilized by C—H···π interactions (Table 1); Cg₁ is the centroid of the C8B–C13B benzene ring.

Experimental

The title compound was synthesized by adding 3-tert-butyl-2-hydroxybenzaldehyde (0.72 ml, 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 e thanol, 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/acetone (2:1 v/v) by slow evaporation of the solvent at room temperature after three weeks.