Solid state structural transformation of bromide coordination polymer to chloride by anion replacement; new precursors for preparation of PbBr2 and PbCl2 nanoparticles

A reversible anion-exchange of 2D lead(II) coordination polymers with the ligand 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene (4-bpdb), from 2D [Pb(4-bpdb)Br2]n (1) to 2D [Pb(4-bpdb)Cl2]n (2) coordination polymer by solid state anion-replacement processes under mechanochemical reactions, has been studied. The reversible solid state structural transformations of compound 1 to compound 2 by anion-replacement have been verified by PXRD and IR spectroscopy. PbBr2 and PbCl2 nanoparticles were obtained by thermal decomposition of compounds 1 and 2 in oleic acid as surfactant at 180 °C under an air atmosphere. These nanoparticles were characterized by powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM).