The one-dimensional organic inorganic hybrid compound poly[(diethylenetriamine)tetra-μ-iodido-dilead(II)]

A new organic–inorganic hybrid, [Pb2I4(C4H13N3)]n, was obtained by the reaction of C4N3H10 and PbI2 at room temperature. The structure is a three-dimensional polymer resulting from the association of PbI6 octahedra and a mixed lead organic–inorganic PbI4(C4N3H13) coordination polyhedron. Both Pb atoms, two I atoms and one N atom lie on a mirror plane. N—H⋯I hydrogen bonds further connect the organic unit and some I atoms.

A new organic-inorganic hybrid, [Pb 2 I 4 (C 4 H 13 N 3 )] n , was obtained by the reaction of C 4 N 3 H 10 and PbI 2 at room temperature. The structure is a three-dimensional polymer resulting from the association of PbI 6 octahedra and a mixed lead organic-inorganic PbI 4 (C 4 N 3 H 13 ) coordination polyhedron. Both Pb atoms, two I atoms and one N atom lie on a mirror plane. N-HÁ Á ÁI hydrogen bonds further connect the organic unit and some I atoms.
Supplementary data and figures for this paper are available from the IUCr electronic archives (Reference: DN2346).

Comment
The basic structure building block of this compound is made up of lead iodide octahedral [PbI 6 ] and a mixed lead organicinorganic PbI 4 (C 4 N 3 H 13 ) coordination polyhedron (Fig 1). Both Pb atoms , two I atoms and one N atom lie on a mirror plane. Atom Pb1 is located in the octahedral cavity of the inorganic chains while Pb2 is responsible of the connectivity between organic moiety and inorganic chains. To our knowledge, this is the first report of an organic-inorganic hybrid exhibiting this kind of lead connectivity.
A part of the inorganic back bone is staked as single chains of edge sharing Pb1I 6 octahedra, as shown in Fig 2. The halide atoms I3 are responsible for the edge sharing between Pb1I 6 neighboring octahedron to join infinite one dimensional chain (parallel to b axis). Within the octahedra the bond lengths around Pb1 range from 3.182 (2) (Wang et al. 1995). Note that the regular octahedrons are a characteristic feature often encountered in the low dimensional lead iodide structures (Zhu et al., 2004).
As mentioned above, C 4 N 3 H 13 is in combination with inorganic moiety by three Pb2-N non covalent interaction and hydrogen bonds. The non centrosymmetric organic molecule is slightly twisted around the C-C bond as reflected by a torsion angle of 25.1 (14)°. Bond distances and angles appear to be within normal range.
It is note worthy that the yellow color observed for the title compound is in good accordance with a low dimensional network of lead octahedral Papavassiliou et al., 1999).

Experimental
An aqueous solution of HI was added to the diethylentriamin to synthesis C 4 H 13 N 3 I 3 salts. Under ambient conditions, stoechiometric amounts of C 4 H 13 N 3 I 3 and PbI 2 with excess HI (to improve PbI 2 solubility), were sailed in DMF. The resulting solution was kept at room temperature. Yellow needle-like crystals are obtained five weeks later.

Special details
Experimental. Number of psi-scan sets used was 4 Theta correction was applied. Averaged transmission function was used. No Fourier smoothing was applied (North et al.,1968).
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 )