A Novel Zr-Based Porous Coordination Polymer Containing Azobenzenedicarboxylate as a Linker

A novel porous coordination polymer (PCP), Zr-abdc, composed of Zr-based secondary building units (SBUs), [Zr6O4(OH)(4)](12+), and 4,4'-azobenzenedicarboxylate (abdc(2-)) linkers, has been synthesized by a modulated synthetic approach. In accord with the twelve-fold connecting SBU, Zr-abdc has a topology similar to the PCP series UiO-66-UiO-68, which is proposed from single-crystal XRD and powder (P) XRD experiments. The linkers are strongly disordered, which made it impossible to determine the exact structure. The compound was further characterized by thermogravimetric analysis, scanning electron microscopy and Ar sorption measurements. Soxhlet extraction with ethanol instead of simple washing was helpful to remove guest molecules present in the pores after the synthesis. PXRD patterns measured at elevated temperatures show that a material stable up to 400 degrees C in air was obtained. After activation, it showed a specific surface area of 3000 m(2)g(-1) and a pore volume of 1.41 cm(3)g(-1).