Cycloruthenated Compounds - Synthesis and Applications

The syntheses of cycloruthenated compounds by several methods, and especially by the C-H activation pathway, have been reviewed. Many ruthenium-containing starting materials lead to these interesting organometallic compounds, which have found various applications in different fields of chemistry. Their reactivity highlights both the variety of reactions that were found to occur at the Ru-C bonds as well as the inertness of the organometallic moiety when these species are exposed to strongly oxidizing molecules or to reactive halogenation reagents. Their use as catalyst precursors showed them to be particularly efficient for hydrogenation reactions, either by H-2 or by hydride transfer. Physicochemical characteristics of cycloruthenated complexes include: (i) a cathodic shift of the electrochemical potentials corresponding to various redox couples, (ii) a bathochromic shift of UV/Vis absorption bands, (iii) valuable luminescence properties. Dinuclear cycloruthenated complexes display specific properties connected to interactions between the metals, such as strong electronic coupling, evidenced by intervalence bands of mixed-valence species, or efficient energy transfer. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)