Solid state syntheses of nano lead(II) iodide triazole carboxylate coordination polymer from its bromide/thiocyanate/chloride analogs via mechanochemical crystal to crystal transformations

Irreversible crystal-to-crystal transformations of 3D lead(II) coordination polymers with the ligand 1H-1,2,4-triazole-3-carboxylic acid (HL), [Pb(L)(mu(2)-Br)(H2O)](n) (1), [Pb(L)(mu(1,1)-NCS)(H2O)](n) (2) and [Pb(L)(mu(2)-Cl)(H2O)](n) (3) to 3D supramolecular compound [Pb(L)(mu(2)-I)](n) (4) by solid state anion-replacement processes under mechanochemical reactions, have been studied. The thermal stabilities of compounds 1-4 were studied by thermogravimetric and differential thermal analyses. The irreversible solid state structural transformations of compounds 1-4, by anion-replacement processes under mechanochemical reaction, have been verified by PXRD measurements. Nanoparticles of compounds 1 and 2 were synthesized by sonochemical process and characterized by scanning electron microscopy (SEM), powder X-ray diffraction, IR spectroscopy, elemental analyses, thermogravimetric and differential thermal analyses. The SEM images showed that no morphology change occurs during solid state anion-replacements of nanocrystals. (C) 2013 Elsevier B.V. All rights reserved.