Glucose oxidase mimicking half-sandwich nickel(II) complexes of coumarin substituted N-heterocyclic carbenes as novel molecular electrocatalysts for ultrasensitive and selective determination of glucose.

Glucose oxidase mimicking nickel-based porous structures with organic anchors are developed as cheap and reliable electrochemical sensors for the quantitative detection of glucose. A series of sterically and electronically modulated, air- and moisture-stable half-sandwich nickel(II) NHC complexes were prepared and characterized. Under the optimized electrocatalytic conditions, the nickel complex immobilized glassy carbon electrodes (GCEs) displayed high sensitivity (0.663, 1.280, 1.990 and 0.182 μA/μM) towards glucose detection, which is much higher than that of 3D porous nickel networks. The limit of detection of modified GCEs is found in the range 1.56-2.09 μM with much wider linear sensing range, and having a catalytic rate constant of 0.273 × 103 M-1s-1. Finally, the selectivity of the modified GCEs towards glucose in presence of other blood constituents was also evaluated.