SYNTHESIS AND ELECTROCHEMICAL-BEHAVIOR OF RUTHENIUM(II) ARENE COMPLEXES - X-RAY CRYSTAL-STRUCTURE OF (ETA(6)-4-METHYLISOPROPYLBENZENE) (ETA(6)-FLUORENE) RUTHENIUM(II)

Cleavage of the chloro-bridged Ru(II) dimer, [(4-methylisopropylbenzen e)Ru(Cl)2]2 with AgBF4 in acetone yields the solvated [4-methylisoprop ylbenzene]Ru(II) dication monomer which reacts with naphthalene, anthr acene, phenanthrene, 9,10-dihydroanthracene, fluorene, cis-stilbene, t rans-stilbene, and coronene to form stable Ru(II) sandwich complexes i n good yield. The compounds were characterized by C-13 and H-1 NMR spe ctroscopy, and an investigation of their electrochemical properties sh owed that all could be reduced in nitromethane solvent. An X-ray cryst al structure determination of the [eta6-4-methylisopropylbenzene] (eta 6-fluorene)Ru(II) complex verifies the eta6-binding of the arene ligan ds. The Ru atom is positioned midway between the two arene rings which are separated by 3.450 angstrom. The crystals are triclinic, space gr oup P1BAR, with lattice constants a = 10.304(2) angstrom, b = 10.355(3 ) angstrom, c = 12.210(2) angstrom, alpha = 101.470, beta = 98.91(1)-d egrees, gamma = 111.05(2)-degrees, and V = 1154.5(4) angstrom3. Conver gence to conventional R values of R = 0.0373 and R(w) = 0.0563 with a goodness-of-fit of 1.07 was obtained for 333 variable parameters and 3 035 reflections with I > 0sigma (I).