Substitutional disorder in bis­[(cyanato-κO)/hydroxido(0.5/0.5)](5,10,15,20-tetra­phenyl­porphyrinato-κ4 N)tin(IV)

Imen Ben Moussa; Mohamed Salah Belkhiria; Shabir Najmudin; Cecilia Bonifacio; Habib Nasri

doi:10.1107/S1600536811021544

. 2011 Jun 11;67(Pt 7):m903–m904. doi: 10.1107/S1600536811021544

Substitutional disorder in bis[(cyanato-κO)/hydroxido(0.5/0.5)](5,10,15,20-tetraphenylporphyrinato-κ⁴ N)tin(IV)

Imen Ben Moussa ^a, Mohamed Salah Belkhiria ^a, Shabir Najmudin ^b, Cecilia Bonifacio ^c, Habib Nasri ^a,^*

PMCID: PMC3152010 PMID: 21836891

Abstract

The title complex, [Sn^IV(C₄₄H₂₈N₄)(CNO)(OH)], exhibits substitutional disorder of the OH⁻ and OCN⁻ axial ligands. Thus, the cyanato-O ligand and the hydroxyl group bonded to the central Sn^IV atom share statistically the axial position. The Sn^IV ion is hexacoordinated by the four N atoms of the pyrrole rings of the tetraphenylporphyrin (TPP) and the O atoms of the two disordered OCN⁻ and OH⁻ axial ligands. The equatorial tin–pyrrole N atom distance (Sn—N_p) is 2.100 (2) Å and the axial Sn—O(OCN) or Sn—O(OH) bond length is 2.074 (2) Å.

Related literature

For a review of porphyrin complexes, see: Scheidt (2000 ▶). For the synthesis of tin(IV) porphyrin species, see: Fallon et al. (2002 ▶); Martelli et al. (2009 ▶). For comparative bond lengths, see: Allen et al. (1987 ▶); Smith et al. (1991 ▶). For a description of the Cambridge Structural Database, see: Allen (2002 ▶).

Experimental

Crystal data

[Sn(C₄₄H₂₈N₄)(CNO)(OH)]
M _r = 790.42
Monoclinic,
a = 11.2943 (6) Å
b = 12.6972 (7) Å
c = 13.0711 (7) Å
β = 114.251 (2)°
V = 1709.06 (16) Å³
Z = 2
Mo Kα radiation
μ = 0.80 mm⁻¹
T = 293 K
0.20 × 0.18 × 0.12 mm

Data collection

Bruker APEXII CCD area-detector diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2007 ▶) T _min = 0.870, T _max = 0.954
27811 measured reflections
5968 independent reflections
5241 reflections with I > 2σ(I)
R _int = 0.028

Refinement

R[F ² > 2σ(F ²)] = 0.039
wR(F ²) = 0.097
S = 1.13
5968 reflections
250 parameters
H-atom parameters constrained
Δρ_max = 0.73 e Å⁻³
Δρ_min = −1.34 e Å⁻³

Data collection: APEX2 (Bruker, 2007 ▶); cell refinement: SAINT (Bruker, 2007 ▶); data reduction: SAINT; 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, 1997 ▶); software used to prepare material for publication: publCIF (Westrip 2010 ▶).

Supplementary Material

Crystal structure: contains datablock(s) I, global. DOI: 10.1107/S1600536811021544/dn2696sup1.cif

e-67-0m903-sup1.cif^{(19.3KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536811021544/dn2696Isup2.hkl

e-67-0m903-Isup2.hkl^{(286.3KB, hkl)}

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

Acknowledgments

We are grateful to the Fundacão para a Ciência e Tecnologia (FCT, Portugal) for support through projects SFRH/BPD/24889/2005 and PTDC/BIA-PRO/103980/2008 and for funding the purchase of the single-crystal diffractometer. We thank Paula Brandão from the Universidade de Aveiro for the crystal mounting and data collection.

supplementary crystallographic information

Comment

The search in the Cambridge Crystallographic Database (version 5.32 with addenda up to November 26, 2010; Allen, 2002) shows that the majority of the reported X-ray molecular structures of porphyrin tin(IV) complexes are hexa-coordinated type [Sn^IV(Porph)(X)₂] for which X is an anionic unidentate ligand bonded to the tin(IV) ion through the oxygen atom. To the best of our knowledge, there is no X-ray molecular structure of a tin(IV) cyanato-O porphyrin species reported in the literature.

The bis{(cyanato-O)/(hydroxo)(0.5/0.5) }(5,10,15,20-tetraphenylporphyrin)tin(IV) complex [Sn^IV(C₄₄H₂₈N₄)(OCN)(OH)] exhibits substitutional disorder of both thiocyanato-O and hydroxo ligands with equal occupancy factor of 0.5. The tin atom which is octahedrally coordinated lies on an inversion center (Fig. 1).

The equatorial tin–pyrrole N atom distance (Sn—N_p) is 2.100 (2) Å which is normal for tin(IV) porphyrin species. The Sn—O(OH) distance is 2.088 (6) Å which is longer than the one of the related species [Sn^IV(TPP)(OH)₂] (2.023 (4) Å) (Smith et al., 1991). The Sn—O(OCN) bond lengh value is 2.059 (8) Å which is close to those of related porphyrin species, i.e, for [Sn^IV(TTP)(OC₆H₅)₂] (TTP is the meso-tetrakis(p-tolyl)porphyrin) (Fallon et al., 2002) the Sn—O(OPh) distance is 2.055 (2) Å.

There are no intermolecular or intramolecular hydrogen bonds in the structure of (I). The packing diagram for (I) (Fig.2) is simple; there is no evidence for intermolecular π -π bonding between the faces of the porphyrin cores in compound (I). The absence of the π-π interactions results mainly in the steric restrictions requirements of the phenyl groups that determine the packing environment.

Experimental

The reaction of the [Sn^IV(TPP)(OH)₂] complex (30 mg, 0.037 mmol) (Martelli et al., 2009) with an excess of sodium cyanate, NaOCN (85 mg, 1.31 mmol) and 18-crown-6 (90 mg, 0.34 mmol) in dichloromethane (4 ml) give a pink-violet solution. Crystals of the title complex were obtained by diffusion of ether through the dichloromethane solution.