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

The title complex, [SnIV(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 SnIV atom share statistically the axial position. The SnIV 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—Np) is 2.100 (2) Å and the axial Sn—O(OCN) or Sn—O(OH) bond length is 2.074 (2) Å.

The title complex, [Sn IV (C 44 H 28 N 4 )(CNO)(OH)], exhibits substitutional disorder of the OH À and OCN À 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 À and OH À 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 .

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 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)(OC 6 H 5 ) 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.

Refinement
The position of the O atoms of the NCO and OH couldn't be separated and were located on the same site using the EXYZ and EADP commands within SHELXL-97 (Sheldrick, 2008).
Hydrogen atoms were placed using assumed geometrically idealized positions (C-H aromatic = 0.95 Å) and constrained to ride on their parent atoms, with U(H) = 1.2Ueq(C

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.