OXIDATION OF ISOMERIC ETA(6)-FLUORENYLCHROMIUMTRICARBONYL AND ETA(5)-FLUORENYLCHROMIUMTRICARBONYL ANIONS

The oxidation of the carbon-centered [(eta(6)-C13H9)Cr(CO)(3)](-) anio n (1(-)) results in formation of (6):eta(6)-9,9-bifluorenyl)bis-chromi umtricarbonyl (3) due to coupling of the intermediate carbon-centered radical (1(.)). The oxidation of the metal-centered anion [(eta(5)-C13 H9)Cr(CO)(3)](-) (2(-)), which is isomeric to the 1(-) anion, gives an equilibrium mixture of the chromium-centered radical {(eta(5)-C13H9)C r(CO)(3)}(.) (2(.)) and its dimer [(eta(5)-C13H9)Cr(CO)(3)](2) (6). Ra dical 2(.) readily reacts with Mel and the solvent (THF): the resultin g derivatives, (eta(5)-C13H9)Cr(CO)(3)R (R = Me (10); R = H (7)), unde rgo fast ricochet inter-ring eta(5)-->eta(6) rearrangements into (eta( 6)-9R-C13H9)Cr(CO)(3) (R = CH3 (9); R = H (4)).