Poly[1,4-bis(ammoniomethyl)cyclohexane [di-μ-chlorido-dichloridoplumbate(II)]]

The title compound, {(C8H20N2)[PbCl4]}n, crystallizes as an layered inorganic–organic hybrid perovskite-type structure. Corner-sharing PbCl6 octahedra extend parallel to the ac plane. Adjacent layers are staggered relative to one another, with diammonium cations separating these layers. The cations exhibit symmetry and interact with the inorganic sheets via N—H⋯Cl hydrogen bonding in the right-angled halogen sub-type of the terminal halide hydrogen-bonding motif.

The title compound, {(C 8 H 20 N 2 )[PbCl 4 ]} n , crystallizes as an layered inorganic-organic hybrid perovskite-type structure. Corner-sharing PbCl 6 octahedra extend parallel to the ac plane. Adjacent layers are staggered relative to one another, with diammonium cations separating these layers. The cations exhibit 1 symmetry and interact with the inorganic sheets via N-HÁ Á ÁCl hydrogen bonding in the right-angled halogen subtype of the terminal halide hydrogen-bonding motif.

Comment
Inorganic-organic hybrid compounds have been investigated for their semiconduting and electronic properties (Mitzi et al., 2001). For literature regarding hydrogen bonding nomenclature for inorganic-organic hybrids, see: Mitzi (1999). The title structure ( Fig. 1) is one of three 2-dimensional hybrid structures that we have synthesized encorporating this diammonium cation. The structures differ in terms of their halogen ligands, which include chloride (presented here), bromide (Rayner & Billing, 2010a) and iodide (Rayner & Billing, 2010b). The bromide and iodide hybrids crystallize in the monoclinic system with space group P2 1 /c while the chloride hybrid crystallizes in the orthorhombic, Pnma system.
In the title structure the lead-chloride octahedra from alternate layers that are staggered relative to one another (Fig.   2). In all three structures only the trans form of the cation has been observed, giving the cation 1 symmetry (Fig. 3). The ammonium cations interact with the inorganic layer via N-H···X (X = Br, I and Cl) hydrogen bonding in the right-angled halogen subtype of the terminal halide hydrogen bonding motif (Mitzi, 1999). Similar inorganic-organic hybrid structures have been reported (Billing & Lemmerer, 2006;Dobrzycki & Woźniak, 2009), however very few hybrids encorporating diammonium cations have been synthesized.

Experimental
A mixture of 0.052 g (0.19 mmol) PbCl 2 and 0.030 g (0.21 mmol) 1,4-bis-(aminomethyl)-cyclohexane (mixture of isomers) was dissolved in 5 ml HCl at 383 K and slow cooled at a rate of 0.069 K/min to yield colourless, plate-shaped single crystals suitable for X-ray analysis.

Special details
Experimental. Numerical intergration absorption corrections based on indexed crystal faces were applied using the XPREP routine (Bruker, 2005) 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.
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.