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 {[Co₅(L)₂(OH)₂(OH₂)₂(H₂O)₄]·2DMF·H₂O}_<i>n</i> (<b>1</b>) with pentanuclear [Co₅(μ₃-OH)₂(μ₂-OH₂)₂]⁸⁺ cluster was prepared. The glassy carbon electrode was modified by <b>1</b>, 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@<b>1</b> 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@<b>1</b> was greatly increased with low detection limit (1.32 μM) and good selectivity and sensitivity (0.135 μA μM^-1), which promote the application of MOF-template porous composites as advanced electrochemical sensor materials. Furthermore, <b>1</b> shows an interesting magnetic spin-glass slow dynamics for the existing of peculiar pentanuclear Co(II) clusters.