New synthetic routes to cationic arene π-complexes of transition metals

A review is given of the authors' studies on the development of new methods for the synthesis of cationic arene complexes of transition metals. The synthesis in strong protic acids facilitated obtaining π-arene cations of Mn, Re, Ru, Os, Co, Rh and Ir. New nonacidic methods allowed the set of available cationic arene π-complexes of Mn, Ru, Rh and Ir to be increased considerably. Based on the developed methods a number of previously unknown binuclear organometallic cations are obtained.