Heterobimetallic iridium–ruthenium assemblies through an ambidentate triazole-diylidene ligand: electrochemical properties and catalytic behavior in a cascade reaction

摘要

The preparation in high yield of a (p-cymene)-RuII(triazolium-ylidene) complex allows the synthesis of anheterobimetallic IrIII−RuII complex with a triazole-diylidenebridge. The same complex can also be prepared by startingfrom the previously reported complex Cp*IrIII(triazoliumylidene). A full electrochemical study of the heterobimetalliccomplex has been performed, and the results have beencompared with those for the related homobimetallic triazolediylidene bridged complexes of ruthenium and iridium, wherea weak metal−metal interaction (class II, according to theRobin and Day classification) has been detected. The Ir−Ru complex and some other related (p-cymene)Ru(NHC) complexeshave been tested in a new tandem process, implying the chelation-assisted arylation of arylpyridines with 1-(4-halophenyl)ethanol. The arylation is accompanied by the transformation of the alcohol into a ketone, in the presence ofacetone, through an Oppenauer oxidation process.