Reversible solid-gas and solid-solid transformation of lead(II)-phenylalanine coordination polymers

A lead(II) supramolecular [Pb(OH2)2(Phe)2(NO3)]n[NO3] (1), polymerizes on grinding the solid with 1 mmol NaOH and also with NH3 vapors to form the 2D coordination polymer, [Pb(Phe)2]n (2), and this process could be reversible with solid-gas reaction to introduce compound 1. Pb3O4 and mixture phase of PbO nanoparticles were obtained by direct calcination of compounds 1 and 2 at 400 °C.