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Pores of uniform size are found in the title compound (a structural model is shown on the right), in which parallel layers of a zirconium phosphate are joined by biphenyl “pillars”. The structure of this polymer, which may have potential as a shape‐selective catalyst or a molecular sieve, is reminiscent of the architecture of a Greek temple.

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The first crystalline microporous zirconium phosphonate metal-organic framework (UPG-1) was synthesized using the novel tritopic ligand 2,4,6-tris(4-(phosphonomethyl)phenyl)-1,3,5-triazine. Its crystal structure was solved ab initio from laboratory powder X-ray diffraction data. UPG-1 displays remarkable thermal stability and hydrolysis resistance and has a good absorption affinity towards n-butane and CO2.

M = 1208.0, yellow. triclinic PI. 7 = 95.47(2) . I,'= 2361.5 A3. 2 =2. pL,s,cd = 1.699. p (Cu,,) = 33.755 cm-'. 4921 reflections (3 < 0 < 51 . k h + k + I ) Mere collected at -100 C on a crystal of 0.26 x 0.20 x 0.09 mm. empirical absorption correction were applied.

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Mixed membrane matrices (MMMs) made up with Nafion and nanocrystals of zirconium metal-organic framework (MOF) UiO-66 or the analogous sulfonated SOH-UiO-66 were prepared by varying the filler loading and the size of the crystals. The combined effects of size and loading, together with the presence of sulfonic groups covalently linked to the MOFs, were studied with regard to the conductivity and mechanical properties of the obtained composite matrices. A large screening of membranes was preliminarily made and, on the most promising samples, an accurate conductivity study at different relative humidities and temperatures was also carried out. The results showed that membranes containing large crystals (200 nm average size) in low amounts (around 2%) displayed the best results in terms of proton conductivity values, reaching values by 30% higher than those of pure Nafion, while leaving the mechanical properties substantially unchanged. On the contrary, MMMs containing MOFs of small size (20 nm average size) did not show any conductivity improvements if compared to pure Nafion membranes. The effect of MOF sulfonation was negligible at low filler loading whereas it became important at loading values around 10%. Finally, membranes with a high filler loading (up to 60 wt %) of sulfonated UiO-66 showed a slight reduction of conductivity in comparison with membranes loaded at 20% of nonsulfonated ones.