Tetraethylammonium dicyanido(5,10,15,20-tetraphenylporphyrinato)ferrate(III) dichloromethane monosolvate

The title compound, (C8H20N)[Fe(C44H28N4)(CN)2]·CH2Cl2 or (Et4N)[Fe(TPP)(CN)2], was recrystallized from dichloromethane–diethyl ether. The compound crystallizes with the two unique halves of the FeIII porphyrinato complex, one tetraethylammonium cation and one interstitial dichloromethane molecule within the asymmetric unit. Both anionic FeIII complexes exhibit inversion symmetry. Both the cation and the solvent molecules show positional disorder. The cation is disordered over two sets of sites with an occupancy ratio of 0.710 (3):0.290 (3); the solvent molecule is disordered over three positions with a 0.584 (6):0.208 (3):0.202 (5) ratio. The crystal packing features columns of [Fe(TPP)(CN)2]− anions that propagate along [001]. The columns further pack into layers that are parallel to (011) and also include the Et4N+ cations. The interstitial CH2Cl2 molecules appear in the interlayer space. This complex may serve as a useful precursor for the assembly of multinuclear and extended CN-bridged complexes for the design of single-molecule and single-chain magnets, respectively.

The title compound, (C 8 H 20 N)[Fe (C 44 H 28 N 4 )(CN) 2 ]ÁCH 2 Cl 2 or (Et 4 N)[Fe(TPP)(CN) 2 ], was recrystallized from dichloromethane-diethyl ether. The compound crystallizes with the two unique halves of the Fe III porphyrinato complex, one tetraethylammonium cation and one interstitial dichloromethane molecule within the asymmetric unit. Both anionic Fe III complexes exhibit inversion symmetry. Both the cation and the solvent molecules show positional disorder. The cation is disordered over two sets of sites with an occupancy ratio of 0.710 (3):0.290 (3); the solvent molecule is disordered over three positions with a 0.584 (6):0.208 (3):0.202 (5) ratio. The crystal packing features columns of [Fe(TPP)(CN) 2 ] À anions that propagate along [001]. The columns further pack into layers that are parallel to (011) and also include the Et 4 N + cations. The interstitial CH 2 Cl 2 molecules appear in the interlayer space. This complex may serve as a useful precursor for the assembly of multinuclear and extended CN-bridged complexes for the design of single-molecule and single-chain magnets, respectively.
The National Science Foundation is gratefully acknowledged for the support of this research via grant CHE-0911109 to MS. supplementary materials Acta Cryst. (2013) 1997) A particular interest in these materials stems from the possibility of a judicious design and preparation of magnetically bistable materials, such as single-molecule and single-chain magnets (SMMs and SCMs). (Shatruk et al., 2009) A prerequisite for the existence of SMM and SCM properties is a significant magnetic anisotropy and high groundstate spin value of the transition metal ion. An effective approach uses a combination of two monometallic building blocks to satisfy both these criteria in the final structure.
A number of recent approaches have considered the mononuclear CN-terminated complexes as metalloligands that can be combined with solvated or partially ligated metal ions to create specific molecular shapes in a predictable (modular) manner. (Schelter et al., 2004 andSchelter et al., 2007) With the goal to prepare such metalloligand that would incorporate a magnetically anisotropic metal center, we turned to iron(III) tetraphenylporphyrinato anion, [Fe(TPP)] -(S = 1/2). It was reported that a reaction between [Fe(TPP)Cl] and KCN leads to the desired salt, K[Fe(TPP)(CN) 2 ], and the crystal structure of this salt was established, (Scheidt et al.,1980) as well as the structure of its close analogue, in which the K + ion was ligated by 18-crown-6 macrocycle. (Li et al., 2009) Nevertheless, reports on oligomeric or polymeric CNbridged structures obtained with the [Fe(TPP) 2 (CN) 2 ]building block are very scarce. (Scott et al., 1994 andCorsi et al., 1999) Therefore, we set out to obtain a convenient, readily soluble precursor that could be used for the preparation of such structures.
A metathesis reaction between K[Fe(TPP)(CN) 2 ] and (Et 4 N)Cl led to the isolation of dark-violet solid, (Et 4 N)[Fe(TPP) (CN) 2 ] that could be readily recrystallized from CH 2 Cl 2 /Et 2 O. The compound is soluble in a variety of organic solvents, including dichloromethane, chloroform, acetonitrile, acetone, and N,N′-dimethylformamide. The results of our current efforts to use this precursor in the preparation of CN-bridged multinuclear assemblies will be reported in due course.

Refinement
The tetraethylammonium cation was disordered over two positions around the central N atom, which were refined under the constraint that the total occupancy of both position is equal to 1. The interstitial dichloromethane molecule was disordered over three positions, the total occupancy of which also was set equal to 1. (An attempt to refine the CH 2 Cl 2 molecule with only two disorder components consisently led to the appearance of significant peaks in the difference Fourier electron density maps.) The isotropic atomic displacement parameters (ADPs) of all C atoms from the three disorder components of the CH 2 Cl 2 molecule were set equal, in order to minimize the correlation with the site occupancy factors (SOFs) and taking into account that these atoms were located nearby one another. The Cl atoms of the CH 2 Cl 2 molecule were refined anisotropically, since the isotropic refinement consistently led to the appearance of significant residual electron density peaks in the vicinity of these atoms. To minimize the correlation between the ADPs and SOFs, the ADPs of the disordered Cl atoms that appeared closer than 1.2 Å to each other were restricted to be similar, using the SIMU instruction in SHELXL.  Approximately octahedral coordination about one Fe III . Displacement ellipsoids are drawn at the 50% probability level.

Tetraethylammonium dicyanido(5,10,15,20-tetraphenylporphyrinato)ferrate(III) dichloromethane monosolvate
Crystal data (C 8   where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.011 Δρ max = 0.40 e Å −3 Δρ min = −0.43 e Å −3 Special details Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'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 R-factors(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.