Diaqua­(5,10,15,20-tetra­phenyl­porphyrinato-κ4 N)magnesium–18-crown-6 (1/1)

Khaireddine Ezzayani; Soumaya Nasri; Mohamed Salah Belkhiria; Jean-Claude Daran; Habib Nasri

doi:10.1107/S1600536813001219

. 2013 Jan 19;69(Pt 2):m114–m115. doi: 10.1107/S1600536813001219

Diaqua(5,10,15,20-tetraphenylporphyrinato-κ⁴ N)magnesium–18-crown-6 (1/1)

Khaireddine Ezzayani ^a, Soumaya Nasri ^a,^*, Mohamed Salah Belkhiria ^a, Jean-Claude Daran ^b, Habib Nasri ^a

PMCID: PMC3569206 PMID: 23424408

Abstract

In the title compound, [Mg(C₄₄H₂₈N₄)(H₂O)₂]·C₁₂H₂₄O₆, the Mg^II cation lies on an inversion center and is octahedrally coordinated by the four N atoms of the deprotonated tetraphenylporphyrin (TPP) ligand and by two water molecules. The asymmetric unit contains one half of the [Mg(TPP)(H₂O)₂] complex and one half of an 18-crown-6 molecule. The average equatorial magnesium–pyrrole N atom distance (Mg—N_p) is 2.071 (1) Å and the axial Mg—O(H₂O) bond length is 2.213 (1) Å. The crystal packing is stabilized by two O—H⋯O hydrogen bonds between coordinating water molecules and adjacent 18-crown-6 molecules, and exhibits a one-dimensional supramolecular structure along the a axis. The supramolecular architecture is futher stabilized by weak C—H⋯π interactions. The 18-crown-6 molecule is disordered over two sets of sites with an occupancy ratio of 0.8:0.2.

Related literature

For general background to magnesium porphyrin species and their applications, see: Ghosh et al. (2010 ▶). For related structures, see: Belghith et al. (2012 ▶); McArdle (1995 ▶); McKee et al. (1984 ▶); Choon et al. (1986 ▶); McKee & Rodley (1988 ▶); Gryz et al. (2007 ▶); Imaz et al. (2005 ▶). For a description of the Cambridge Structural Database, see: Allen (2002 ▶).

Experimental

Crystal data

[Mg(C₄₄H₂₈N₄)(H₂O)₂]·C₁₂H₂₄O₆
M _r = 937.36
Triclinic,
a = 8.1440 (3) Å
b = 12.3080 (4) Å
c = 12.4170 (4) Å
α = 86.894 (3)°
β = 75.163 (3)°
γ = 79.529 (3)°
V = 1183.06 (7) Å³
Z = 1
Mo Kα radiation
μ = 0.10 mm⁻¹
T = 180 K
0.56 × 0.51 × 0.19 mm

Data collection

Oxford Diffraction Xcalibur (Sapphire1) diffractometer
Absorption correction: multi-scan (CrysAlis RED; Oxford Diffraction, 2009 ▶) T _min = 0.946, T _max = 0.981
23613 measured reflections
4650 independent reflections
4013 reflections with I > 2σ(I)
R _int = 0.031

Refinement

R[F ² > 2σ(F ²)] = 0.044
wR(F ²) = 0.118
S = 1.04
4650 reflections
400 parameters
119 restraints
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.46 e Å⁻³
Δρ_min = −0.28 e Å⁻³

Data collection: CrysAlis CCD (Oxford Diffraction, 2009 ▶); cell refinement: CrysAlis RED (Oxford Diffraction, 2009 ▶); data reduction: CrysAlis RED; program(s) used to solve structure: SIR2004 (Burla et al., 2005 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: ORTEPIII (Burnett & Johnson, 1996 ▶) and ORTEP-3 for Windows (Farrugia, 2012 ▶); software used to prepare material for publication: SHELXL97.

Supplementary Material

Click here for additional data file.^{(37.4KB, cif)}

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536813001219/xu5669sup1.cif

e-69-0m114-sup1.cif^{(37.4KB, cif)}

Click here for additional data file.^{(223.2KB, hkl)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536813001219/xu5669Isup2.hkl

e-69-0m114-Isup2.hkl^{(223.2KB, hkl)}

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

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

Cg2 and Cg4 are the centroids of the N2/C6–C9 and C17–C22 rings, respectively.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
O1—H1O1⋯O2A	0.97 (2)	2.08 (2)	2.984 (2)	153 (2)
O1—H2O1⋯O2A ⁱ	0.97 (2)	2.22 (2)	3.105 (2)	150 (2)
O1—H1O1⋯O2B	0.97 (2)	2.33 (2)	3.297 (10)	170 (2)
O1—H2O1⋯O2B ⁱ	0.97 (2)	2.19 (2)	2.962 (8)	135 (1)
C15—H15⋯Cg4ⁱⁱ	0.93	2.96	3.730 (2)	141
C27A—H27A⋯Cg2ⁱⁱⁱ	0.97	2.86	3.671 (5)	142
C26B—H26D⋯Cg2	0.97	2.89	3.678 (11)	139
C27B—H27D⋯Cg2ⁱⁱⁱ	0.97	2.94	3.715 (17)	139

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

Acknowledgments

The authors gratefully acknowledge financial support from the Ministry of Higher Education and Scientific Research of Tunisia.

supplementary crystallographic information

Comment

In continuation of our research on the crystal structures of porphyrin complexes (Belghith et al., 2012) we herein report the synthesis and crystal structure of the bis-aqua-Mg tetraphenylporhyrin derivative [Mg(TPP)(H₂O)₂].(18-C-6). In this complex, the coordination geometry of the Mg²⁺ ion is octahedral with four Mg—N(pyrrole) bonds in the equatorial porphyrin plane and two Mg—O bonds with the two symmetry related water axial ligands. The average equatorial distance (Mg–Np) equal to 2.071 (1) Å lies in the range [2.065 (4) - 2.092 (7) Å] of the related porphyrin species [Mg(TPP)(4-pic)₂] (4-pic = 4-picoline: C₆H₇N) (McKee et al., 1984) and [Mg(TPP)(H₂O)] (Choon et al., 1986).

The axial Mg—O(H₂O) bond length [2.213 (1) Å] is quite longer than in the related derivative [Mg(TPP)(H₂O)] (2.053 (5) Å) (McKee & Rodley, 1988) but is within the range [2.063 (2) - 2.75 (2) Å] found for several magnesium-aqua non-porphyrin complexes (CSD refcodes DEZNIG; Gryz et al., 2007 and FIVYEP; Imaz et al., 2005) (CDS, version 5.32 Allen, 2002).

The crystal structure of our derivative resembles to one-dimensional coordination polymer where each one of two [Mg(TPP)] moieties is linked to an ether crown 18-C-6 molecule via H bonds between the oxygen atom O2A of this species and the O1 atom of the water axial ligand of the [Mg(TPP)(H₂O)₂] derivative (Fig. 2).

These linear chains are parallel to the a axis and are mainly sustained by weak C—H···Cg interactions, where Cg is the centroid of the pyrrole or phenyl rings (Table 1).

Experimental

To a solution of [Mg(TPP)] (15 mg, 0.024 mmol) in chlorobenzene (15 ml) was added an excess of (18-crown-6) (100 mg, 0.378 mmol). The reaction mixture was stirred at room temperature and at the end of the reaction, the color of the solution gradually changes from purple to blue – purple. The resulting material was crystallized by diffusion of hexanes through the chlorobenzene solution which yielded [Mg(TPP)(H₂O)₂].(18-C-6). The two water molecules coordinated to the magnesium come from the hygroscopic 18-crown-6 reagent used in excess.