Cd(II) Coordination Polymers with 9-Anthracenyl-4′-benzoate and Bispyridyl Linkers: Structures and Supercapacitor Performance

Three novel cadmium(II)-based coordination polymers (CPs) have been successfully synthesized and structurally characterized, namely, [Cd(9-AnBz)4(4,4′-bpy)2] (CP1), [Cd(9-AnBz)4(4,4′-bpdb)2] (CP2), [Cd(9-AnBz)2(3,3′-bpdb)2(H2O)2]·H2O (CP3) (where 9-AnBz = 9-anthracenyl-4′-benzoate, 4,4′-bpy = 4,4′-bipyridine, 4,4′-bpdb = 1,4-bis(4′-pyridyl)-2,3-diaza-1,3-butadiene, 3,3′-bpdb = 1,4-bis(3′-pyridyl)-2,3-diaza-1,3-butadiene). Single-crystal X-ray diffraction unambiguously confirmed their structural architectures, with CP1 adopting a two-dimensional coordination polymeric network, CP2 adopting a double-stranded ladder-like coordination polymer, and CP3 adopting a linear zigzag one-dimensional coordination polymeric chain. These three CPs have been explored for their performances in supercapacitor applications. CP1 with a two-dimensional network structure exhibited the highest electrochemical performance in this series, with a prominent current response in CV, and a long, extended discharge capacity in GCD analysis. CP1 delivered a very good specific capacitance of 1323 F g–1 at 3 A g–1, ∼10-fold higher than that of CP2 and CP3. It is anticipated that the two-dimensional layered structure with the shortest intermetallic distance in CP1 facilitates a prominent energy-storage performance.