Porous Crystal Derived from a Tricarboxylate Linker with Two Distinct Binding Motifs

The use of a reduced symmetry organic linker for the preparation of porous coordination polymers is demonstrated. The solvothermal reaction of the unsymmetrically substituted biaryl compound biphenyl-3,4‘,5-tricarboxylic acid with Cu(II) ions produces a [3,4,6]-connected coordination polymer exhibiting very high porosity and surface area (SLangmuir = 3100 m2/g). A striking feature of the structure is its incorporation, in a single material, of both the ubiquitous dinuclear Cu(II) paddlewheel motif and the rarely observed trinuclear Cu(II) cluster. Saturation H2 uptake, measured at 77 K, shows an excess gravimetric uptake of 5.7 wt % at 45 bar with a steep rise at low pressures.