Porous Interpenetrated Zirconium-Organic Frameworks (PIZOFs): A Chemically Versatile Family of Metal-Organic Frameworks

We present the synthesis and characterization of porous interpenetrated zirconium-organic frameworks (PIZOFs), a new family of metal-organic frameworks obtained from ZrCl4 and the rodlike dicarboxylic acids HO2C[PE-P(R-1, R-2)-EP]CO2H that consist of alternating phenylene (P) and ethynylene (E) units. The substituents R-1, R-2 were broadly varied (alkyl, O-alkyl, oligo(ethylene glycol)), including postsynthetically addressable substituents (amino, alkyne, furan). The PIZOF structure is highly tolerant towards the variation of R-1 and R-2. This together with the modular synthesis of the diacids offers a facile tuning of the chemical environment within the pores. The PIZOF structure was solved from single-crystal X-ray diffraction analysis. The PIZOFs are stable under ambient conditions. PIZOF-2, the PIZOF prepared from HO2C[PE-P( OMe, OMe)-EP]CO2H, served as a prototype to determine thermal stability and porosity. It is stable up to 325 degrees C in air as determined by using thermogravimetry and powder X-ray diffraction. Argon sorption isotherms on PIZOF-2 revealed a Brunauer-Emmett-Teller (BET) surface area of 1250 m(2) g(-1) and a total pore volume of 0.68 cm(3) g(-1).