Tuning the topological net of two new copper(II) coordination polymers based on a paddle-wheel secondary building unit via altering the auxiliary ligands

Two new coordination polymers, [Cu(BDC)(L₁)_0.5]_n (1) and [Cu(BDC)(L₂)_0.5]_n (2) [H₂BDC=5-methyl-1,3-benzenedicarboxylic acid, L₁=1,4-bis(2-methyl-imidazol-1-yl) butane and L₂=1,4-bis(1-imidazol-yl)-2,5-dimethylbenzene], were synthesized from Cu(II), H₂BDC, and L₁/L₂. The carboxylate groups in 1 and 2 are bis-monodentate. By changing the N-donor ligands, 1 and 2 exhibit different topologies from a rob topological net to a twofold interpenetrating pcu net; however, they possess the same paddle-wheel secondary building unit in which Cu(II) has square-pyramidal geometry. The thermal stabilities of 1 and 2 are investigated.