Two 3D cupric metal–organic frameworks based on the biphenyl-2,3,3′,5′-tetracarboxylate ligand and possessing 1D nanosized channels

Abstract

From the same starting materials, two novel metal–organic frameworks, namely {(cation)[Cu4(bptca)2(OH)(H2O)2]·x(solvent)}n (1) and {(cation)[Cu3(bptca)2(H2O)3]·y(solvent)}n (2) (H4bptca=biphenyl-2,3,3′,5′-tetracarboxylic acid), have been synthesized through the linkage of Cu2(COO)4 paddle-wheel clusters. The complex 1 possesses both dinuclear [Cu2O2] subunits encapsulated into cage-like units and tetranuclear [Cu4(μ3-OH)2] clusters, which exhibits an unusual 3D 4-nodal (4,4,4,8)-connected network with {412.812.104}{43.83}4{46}{86} topology. Reducing the metal-to-ligand ratio, the other 3D (4,4)-connected framework 2 with {42.84} PtS-type topology was constructed under the intervention of mononuclear Cu(bptca)2 and single Cu2(COO)4 paddle-wheel supporting layers. Notably, both of the frameworks 1 and 2 accommodate infinite open 1D nanosized quadrate channels.