New reversible crystal-to-crystal conversion of a mixed-ligand lead(II) coordination polymer by de- and rehydration.

A reversible crystal-to-crystal transformation of a new 2D lead(II) coordination polymer with the ligand 4-pyridinecarboxylic acid (4-Hpyc), Pb(4-pyc)(Br)(H(2)O) (1) to Pb(4-pyc)(Br) (2) by de- and rehydration, has been observed, and the structures of 1 and 2 have been determined by single-crystal X-ray diffraction. The thermal stabilities of compounds 1 and 2 were studied by thermal gravimetric and differential thermal analyses. Powder X-ray diffraction experiments showed that the structural transformation occurs in the batch powder samples and leads to monophasic products.