New Synthesis and New Bio-Application of Cyclometalated Ruthenium(II) Complexes for Fast Mediated Electron Transfer with Peroxidase and Glucose Oxidase

An easy synthesis of the orthoruthenated compounds [Ru(o-C6H4-X)(LL)(LL‘)]PF6, where X = 2-pyridinyl or CH2NMe2 and LL and LL‘ are 2,2‘-bpy or 1,10-phen type ligands, involves a direct cleavage of the sp2-C−H bonds of 2-phenylpyridine or N,N-dimethylbenzylamine by [(η6-C6H6)Ru(μ-Cl)Cl]2 in MeCN followed by the interaction of the [Ru(o-C6H4-X)(MeCN)4]PF6 formed with LL or LL‘ in refluxing methanol. Cycloruthenated compounds, such as 5b, are oxidized by horseradish peroxidase with the rate constants of 108 M-1 s-1, whereas rates of their reduction by glucose oxidase exceed 107 M-1 s-1.