COMPLEXATION AND AROMATIZATION OF ALPHA,BETA-UNSATURATED CYCLIC-KETONES BY RU(H2O)(6)(2- MOLECULAR-STRUCTURE OF ETA(6)-TOSYLATE)(ETA(5)-HYDROXYCYCLOPENTADIENYL)RU AND OF ETA(6)-1,4-DIHYDROXY-2,3,5,6-TETRAMETHYLBENZE)RU() AND (BZ)RU(H2O)(3)(2+) )

Ruaq(2+)(OTs)(2) complexes in aqueous solution to unsaturated cyclic k etones. These aromatized on heating to pi-arene Ru complexes. Thus, wi th cyclohexenone the main product was Ru(eta(6)-phenol)(2)(2+) 4, alon g with some Ru(eta(6)-phenol)(eta(6)-OTs)(+), 6. Similarly gave cyclop entenone in the presence of various arenes (eta(5)-hydroxycyclopentadi enyl)(eta(6)-arene)(+). Duroquinone complexed to Ruaq(2+) as a monopro tonated hydroquinolate in 2,3,5,6-tetramethyl-1,4-hydroquinone)(eta(6) -OTs), 14. Ru(eta(5)-cycropentadienyl)(eta(6)-OTs), 8, and 14 were cha racterized by single crystal x-ray structure analyses, data see Table 1. Whereas both ligands in 8 are planar, the 1,4-hydroquinone ligand i n 14 shows distinct bending of the COH groups.