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)[Cu 4 (bptca) 2 (OH)(H 2 O) 2 ]· x (solvent)} n ( 1 ) and {(cation)[Cu 3 (bptca) 2 (H 2 O) 3 ]· y (solvent)} n ( 2 ) (H 4 bptca = biphenyl-2,3,3′,5′-tetracarboxylic acid), have been synthesized through the linkage of Cu 2 (COO) 4 paddle-wheel clusters. The complex 1 possesses both dinuclear [Cu 2 O 2 ] subunits encapsulated into cage-like units and tetranuclear [Cu 4 ( μ 3 -OH) 2 ] clusters, which exhibits an unusual 3D 4-nodal (4,4,4,8)-connected network with {4 12 .8 12 .10 4 }{4 3 .8 3 } 4 {4 6 }{8 6 } topology. Reducing the metal-to-ligand ratio, the other 3D (4,4)-connected framework 2 with {4 2 .8 4 } PtS-type topology was constructed under the intervention of mononuclear Cu(bptca) 2 and single Cu 2 (COO) 4 paddle-wheel supporting layers. Notably, both of the frameworks 1 and 2 accommodate infinite open 1D nanosized quadrate channels.