Route to a Family of Robust, Non‐interpenetrated Metal–Organic Frameworks with pto‐like Topology

A combination of topological rules and quantum chemical calculations has facilitated the development of a rational metal–organic framework (MOF) synthetic strategy using the tritopic benzene-1,3,5-tribenzoate (btb) linker and a neutral cross-linker 4,4′-bipyridine (bipy). A series of new compounds, namely [M2(bipy)]3(btb)4 (DUT-23(M), M=Zn, Co, Cu, Ni), [Cu2(bisqui)0.5]3(btb)4 (DUT-24, bisqui=diethyl (R,S)-4,4′-biquinoline-3,3′-dicarboxylate), [Cu2(py)1.5(H2O)0.5]3(btb)4 (DUT-33, py=pyridine), and [Cu2(H2O)2]3(btb)4 (DUT-34), with high specific surface areas and pore volumes (up to 2.03 m3 g−1 for DUT-23(Co)) were synthesized. For DUT-23(Co), excess storage capacities were determined for methane (268 mg g−1 at 100 bar and 298 K), hydrogen (74 mg g−1 at 40 bar and 77 K), and n-butane (99 mg g−1at 293 K). DUT-34 is a non-cross-linked version of DUT-23 (non-interpenetrated pendant to MOF-14) that possesses open metal sites and can therefore be used as a catalyst. The accessibility of the pores in DUT-34 to potential substrate molecules was proven by liquid phase adsorption. By exchanging the N,N donor 4,4′-bipyridine with a substituted racemic biquinoline, DUT-24 was obtained. This opens a route to the synthesis of a chiral compound, which could be interesting for enantioselective separation.