(Cryptand-222)potassium(+) (hydrogensulfido)[5,10,15,20-tetrakis(2-pivalamidophenyl)porphyrinato]ferrate(II)

As part of a systematic investigation for a number of FeII porphyrin complexes used as biomimetic models for cytochrome P450, crystals of the title compound, [K(C18H36N2O6)][FeII(C64H64N8O4)(HS)], were prepared. The compound exhibits a non-planar conformation with major ruffling and saddling distortions. The average equatorial iron–pyrrole N atom [Fe—Np = 2.102 (2) Å] bond length and the distance between the FeII atom and the 24-atom core of the porphyrin ring (Fe—PC= 0.558 Å) are typical for high-spin iron(II) pentacoordinate porphyrinates. One of the tert-butyl groups in the structure is disordered over two sets with occupancies of 0.84 and 0.16.

As part of a systematic investigation for a number of Fe II porphyrin complexes used as biomimetic models for cytochrome P450, crystals of the title compound, [K(C 18 H 36 N 2 O 6 )][Fe II (C 64 H 64 N 8 O 4 )(HS)], were prepared. The compound exhibits a non-planar conformation with major ruffling and saddling distortions. The average equatorial iron-pyrrole N atom [Fe-N p = 2.102 (2) Å ] bond length and the distance between the Fe II atom and the 24-atom core of the porphyrin ring (Fe-P C = 0.558 Å ) are typical for high-spin iron(II) pentacoordinate porphyrinates. One of the tert-butyl groups in the structure is disordered over two sets with occupancies of 0.84 and 0.16.

Experimental
Crystal data [K(C 18 (Simonneux & Le Maux, 2000). In the Cambridge Structural Database (CSD, Version 5.30 of November 2008;Allen, 2002) there are only three structures of iron(II)-thiolate porphyrinates but no structure of hydrosulfido (SH -) iron(II) porphyrinate derivative is reported up to date. We report here the molecular structure of the iron(II) picket fence porphyrin (TpivPP) hydrosulfido species. In the structure of (I), the Fe 2+ cation is coordinated to the sulfur atom of the SHaxial ligand from the pocket side of the TpivPP porphyrin (Fig. 1). The porphinato core undergoes a significant radial expansion in order to accommodate the high-spin Fe 2+ cation. This is illustrated by the long Fe-N p and Fe-P C distances shown by these iron (II) (Scheidt & Reed, 1981;Scheidt, 2000;Hu et al., 2005). This is a stereochemical proof that compound (I) is high-spin (S = 2  et al., 1987). There are no intermolecular or intermolecular 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 pivalamide groups that determine the packing environment.

Experimental
The reaction sequence leading to the formation of compound (I) is not full understood at present. When a chlorobenzene solution of [Fe II (TpivPP)] (Hachem et al., 2009), made in situ, is mixed under argon with excess of cryptand-222 and potassium thioacetate (C 2 H 3 OSK) a red-greenish solution was formed. Crystals of (I) were grown by diffusion of hexanes through the chlorobenzene solution.
supplementary materials sup-2 Refinement Due to the diffraction limitation of the crystals of (I) (at 180 K), the data collection was limited to 23.22° in θ. Hydrogen atoms were calculated at idealized positions and were refined with 1.2 times the isotropic displacement parameter of the corresponding carbon and nitrogen atoms. The H atom pertaining to the hydrosulfido ligand could not be found in a difference Fourier and was not included in the model.
The tert-butyl group of one picket is disordered over two sets. The occupancies of these two positions were refined and then fixed as 0.84 for C62/C63/C64 and 0.16 for C62A/C63A/C64A. The EADP commands in the SHELXL97 (Sheldrick, 2008) software were used to restrain the parameters of the disordered groups. Some anisotropic displacement ellipsoids of another tert-butyl group were rather elongated. This is the case of the anisotropic displacements U22 and U33 of the C29 and C31 carbons of the same tert-butyl group.These parameters were restrained to be the same than those of the third CH 3 group (C30) of the same picket which presents normal ansisotropic displacements for such type of carbon moiety.
At the final stage of refinement, clear evidence of the presence of solvent voids of 241 Å 3 was obtained (containing approximately 84 electrons). Several trials to find a reasonable model for this were unfruitful. Thus, a correction for diffuse effects due to the inclusion of disordered solvent molecules in the crystal structure was made using the SQUEEZE option in

Special details
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq Occ. (