Preparation and characterization of a novel hybrid magnetic semiconductor containing rare, one-dimensional mixed-iodide/chloride anion of lead(II)

A new hybrid inorganic–organic magnetic semiconductor Ni(bipy)₃Pb₂I_4.84Cl_1.16·DMF]_n (bipy=2,2′-bipyridine) containing novel one-dimensional mixed-halide anion of lead(II) was synthesized by reactions of PbI₂, NaI, NiCl₂ and bipy in DMF solution, and structurally characterized by single-crystal X-ray diffraction. It crystallizes in the space group C2/c with a=29.260(8) Å, b=15.602(4) Å, c=23.695(6) Å, β=126.815(°), Z=8, V=8660(4) Å³ and consists of a magnetic cation Ni(bipy)₃]²⁺ in addition to one-dimensional mixed-halide anion, which is built up of face-sharing PbX₆] octahedra. Of the seven crystallographically independent halide sites in this anion, one and five are occupied by Cl and I, respectively, the remaining one has mixed-iodide and -chloride occupancy. The title yellow compound has an optical bandgap of 2.59 eV, and the variable-temperature magnetic susceptibility measurement indicates paramagnetic behavior.