Irreversible conversion of nanoporous lead(II) metal–organic framework to a nonporous coordination polymer upon thermal treatment.

Graphical abstract Irreversible solid-state conversion of [Pb(1,4-BDC)(C 2 H 5 OH)(C 2 H 5 OH)] n (1) nanoflowers, which also recognized as MOF-70, prepared by mechanochemical solid–solid and solid–gas processes, to nonporous coordination polymer of [Pb(1,4-BDC)] n (2) with agglomerated nanoparticle morphology has been observed upon thermal treatment of MOF-70 at 100 °C. This conversion is one of the rare solid-state structural conversions of nanoporous MOF to nonporous coordination polymer. Abstract The reaction between 1,4-benzenedicarboxylic acid and Pb(NO 3) 2 in the presence of hydrogen peroxide and triethylamine with mechanochemical solid–solid and solid–gas processes results in formation of [Pb(1,4-BDC)(C 2 H 5 OH)(C 2 H 5 OH)] n (1) nanoflowers. This compound also recognized as MOF-70. The MOF-70 porosity did not maintain by heating up to 100 °C and converted to nonporous coordination polymer of [Pb(1,4-BDC)] n (2) with agglomerated nanoparticle morphology. Thus the pore destruction in 1 during removal of coordinated EtOH molecules and formation of 2 with higher thermal stability than 1 are two driving force during this irreversible conversion. [ABSTRACT FROM AUTHOR]