BIS(ARENE) COMPLEXES OF RU(II) - SYNTHESIS, CRYSTAL-STRUCTURE AND ELECTROCHEMICAL-BEHAVIOR OF [BIS(ETA(6)-P-ISOPROPYLTOLUENE)RU][BF4](2)

Cleavage of the chloro-bridged Ru-II dimer, [(p-isopropyltoluene)Ru(Cl )(2)](2) with AgBF4 in acetone and refluxing the product in trifluoroa cetic acid with an excess of p-isopropyltoluene leads to the formation of the dicationic bis(arene) Ru-II complex, [(p-isopropyltoluene)(2)R u][BF4](2), in nearly quantitative yield. Strong upfield shifts are ob served in the C-13 NMR spectrum of the arene carbon atoms of p-isoprop yltoluene following coordination and an investigation of the electroch emistry of this complex shows that it undergoes an irreversible reduct ion in nitromethane solvent at -0.78 V versus an Ag/AgCl reference ele ctrode. An X-ray crystal structure determination of the complex shows that the complex consists of a Run center located between two p-isopro pyltoluene ligands that are coordinated in an eta(6) manner. The arene rings are separated by a distance of 3.450 Angstrom and are essential ly coplanar with a dihedral angle of 178.4 degrees. The crystals are m onoclinic, space group P2(1)/n wth lattice constants a = 10.094(2) Ang strom, b = 12.996(3) Angstrom, c = 17.371(3) Angstrom, beta = 94.90(1) degrees and V = 2270.4(8) Angstrom(3). Convergence to conventional R v alues of R = 0.0711 and R(W) = 0.0854 with a goodness-of-fit of 1.15 w as obtained for 280 variable parameters and 2976 reflections with I > 0 sigma(I).