A multifunctional pseudo-polyrotaxane coordination polymer based on the trinuclear cluster [Co3(COO−)4(OH−)2]: Synthesis, structure and properties

Abstract

A trinuclear cobalt-based multifunctional coordination polymer with a dual loop pseudo-rotaxane motif, namely [Co3(DPFE‧H+)2(sdba2−)4(OH−)2](DPFE‧2H+)(CH3CN) (1), has been synthesized by a mixed ligand strategy under hydrothermal conditions (DPFE = 2,7-di(pyridin-4-yl)-9H-fluorene, H2sdba = 4,4′-sulfonyldibenzoic acid). Compound 1 has 1D + zero-dimensional (0D) → 1D armed pseudo-polyrotaxane character, in which the 1D dual ring chain [Co3(COO−)4(OH−)2(sdba2−)4 is threaded by doubly protonated free DPFE ligands. The trinuclear cobalt cluster and π-electron rich system involving the ligands jointly endow compound 1 with magnetism, photocatalytic and electrochemical properties. Magnetic property measurements of 1 indicate that there exists weak antiferromagnetic coupling in the trinuclear [Co3(COO−)4(OH−)2] unit, the experiments of photocatalytic degradation of dyes demonstrated that 1 has good catalytic activity for the degradation of methylene blue (MB) and the electrochemical results show that compound 1 exhibits a specific capacitance of 52.25 F g−1 at a current density of 1 A g−1 and retains 93.75% specific capacitance after 960 cycles.