Resumen de Formation of a Ruthenium Arene Complex, Cyclometallation with a Substituted Benzylamine, and Insertion of an Alkyne.
Michael J. Chetcuti, Vincent Ritleng
A three-part experiment that includes the synthesis of an arene complex, its cyclometallation, and an insertion reaction with the cyclometallated product is presented. The reaction of RuIIICl3·xH2O with 1,3-cyclohexadiene provides the ruthenium�arene complex [RuII(?6-C6H6)(µ-Cl)Cl]2. This is then allowed to react with N,N-dimethylbenzylamine to yield the cycloruthenated complex [RuII(?6-C6H6){2-(CH2NMe2)-C6H4}(CH3CN)](PF6), 2, by intra-molecular C�H activation. Reaction of the latter complex with diphenylacetylene affords the ruthenium(0) sandwich complex [Ru0(?6-C6H6)(?4-C6H4CH2NMe2CPh=CPh-1,2)](PF6), 3, after successive C�C and C�N coupling reactions. The sequence of experiments provides an excellent example of metal-mediated functionalization of a C�H bond and is appropriate for an advanced undergraduate or a graduate lab course. It also provides an opportunity for students to learn standard schlenk techniques. Furthermore, the characterization of the products by 1H NMR spectroscopy demonstrates the utility of 1H NMR not just in organic but also in organometallic chemistry.
