SYNTHESIS AND REDUCTION OF TRIFLUOROMETHYL-SUBSTITUTED ARENECYCLOPENTADIENYLRUTHENIUM SANDWICHES E4CF3)(ETA(6)-C6R6)](-C5ME5)(ETA(6)-C6H5CF3)](+)() (R = H, ME) AND [RU(ETA(5))

Dimer [Ru-2(eta(5)-C5Me4CF3)(2)Cl-2(mu-Cl)(2)] (1) has been prepared b y reaction of RuCl3 .(H2O)(3) with 3,4-tetramethyl-5-(trifluoromethyl) cyclopentadiene in ethanol under reflux. Cationic arenecyclopentadieny l complexes [Ru(eta(5)-C5Me4CF3)(eta(6)-arene)]+PF6- (2(+), arene =C6H 6; 3(+) arene=C6Me6) and [Ru(eta(5)-C5Me5)(eta(6)-C6H5CF3)]+BF4- (4(+) ) were obtained by refluxing [Ru-2(eta(5)- C5Me4CF3)(2)Cl-2(mu-Cl)(2)] (1) or [Ru-2(eta(5)-C5Me5)(2)Cl-2(mu-Cl)(2)] with corresponding arene s in alcohol. The redox properties of 2(+)-4(+) were studied by cyclic voltammetry (CV). All three complexes 2(+)-4(+) are reduced irreversi bly in one-electron process. The values of reduction peak potentials f or 2(+)-3(+) are less negative than those found for eta(5)-C5Me5 analo gues. The reduction of 2(+) and 3(+) with sodium amalgam in tetrahydro furan led to the formation of dimers 2(eta(5)-C5Me4CF3),(2)(mu-eta(5): eta(5)-C6H6C6H6)] (5) and [Ru-2(eta(5)-C5Me4CF3)(2)( mu-eta(5):eta(5)- C6Me6C6Me6)] (6) respectively. The reduction of 4(+) gave a non-identi fiable mixture of neutral products. (C) 1998 Elsevier Science S.A.