Poly[1,4-bis(ammoniomethyl)cyclohexane [di-μ-bromido-dibromidoplumbate(II)]]

The title compound, {(C8H20N2)[PbBr4]}n, crystallizes as an inorganic–organic hybrid with alternating layers of diammonium cations and two-dimensional corner-sharing PbBr6 octahedra extending parallel to the bc plane, which are eclipsed relative to one another. Both PbBr6 octahedra and the organic cation exhibit symmetry. The cations interact via N—H⋯Br 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 )[PbBr 4 ]} n , crystallizes as an inorganic-organic hybrid with alternating layers of diammonium cations and two-dimensional corner-sharing PbBr 6 octahedra extending parallel to the bc plane, which are eclipsed relative to one another. Both PbBr 6 octahedra and the organic cation exhibit 1 symmetry. The cations interact via N-HÁ Á ÁBr hydrogen bonding in the right-angled halogen sub-type of the terminal halide hydrogen-bonding motif.
In the title structure the lead atoms in the PbBr 6 octahedra occupy inversion centers, giving the octahedra 1 symmetry.
The PbBr 6 octahedra share corners to form layers extending parallel to the bc plane. Octahedra from alternate layers are eclipsed 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). Very few inorganic-organic hybrid structures encorporating diammonium cations have been reported (Dobrzycki & Woźniak, 2008;Zhu et al., 2003). 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).

Experimental
A mixture of 0.050 g (0.14 mmol) PbBr 2 and 0.021 g (0.15 mmol) 1,4-bis-(aminomethyl)-cyclohexane (mixture of isomers) was dissolved in 5 ml HBr at 383 K and slowly 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.
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )