Nonenzymatic Glucose Sensing and Magnetic Property Based On the Composite Formed by Encapsulating Ag Nanoparticles in Cluster-Based Co-MOF

Utilizing the oxygen-bridged 5,5'-oxidiisophthalic acid (H4L) linker, one Co(II)-based 3D porous MOF {[Co-5(L)(2)(OH)(2)(OH2)(2)(H2O)(4)]center dot 2DMF center dot H2O}(n) (1) with pentanuclear [Co-5(mu(3)-OH)(2)(mu(2)-OH2)(2)](8+) cluster was prepared. The glassy carbon electrode was modified by 1, and the obtained electrode revealed electrocatalytic performance for glucose oxidation. The porous MOF matrix is beneficial for dispersing Ag nanoparticles evenly in the interior cages or channels, so Ag@1 composite composed of both Ag nanoparticles and MOF was further prepared through deposition-reduction method to enhance electrocatalytic activity. The result demonstrates that the glucose oxidation by Ag@1 was greatly increased with low detection limit (1.32 mu M) and good selectivity and sensitivity (0.135 mu A mu M-1), which promote the application of MOF-template porous composites as advanced electrochemical sensor materials. Furthermore, 1 shows an interesting magnetic spin-glass slow dynamics for the existing of peculiar pentanuclear Co(II) clusters.