PERMERCURATION OF FERROCENES AND RUTHENOCENES - NEW APPROACHES TO COMPLEXES BEARING PERHALOGENATED CYCLOPENTADIENYL LIGANDS

Treatment of ferrocene with mercuric trifluoroacetate (10 equiv) and m ercuric oxide (5 equiv) in 1:1 diethyl ether/ethanol afforded decakis[ (trifluoroacetoxy)mercurio]ferrocene (60%) as a yellow-orange powder. Reaction with cupric chloride dihydrate in acetone yielded mixtures of partially chlorinated ferrocenes, of which decachloroferrocene was a minor component. Treatment of ferrocene with mercuric acetate (10 equi v) in refluxing dichloroethane for 18 h afforded decakis(acetoxymercur io)ferrocene (95%). Halogenation of decakis(acetoxymercurio)ferrocene with cupric chloride dihydrate in acetone, potassium tribromide in wat er, or potassium triiodide in water afforded decachloroferrocene (27%) , decabromoferrocene (60%), and decaiodoferrocene (67%), respectively. Examination of the H-1 NMR spectra of crude decachloroferrocene and d ecabromoferrocene revealed small amounts (less-than-or-equal-to 5%) of partially halogenated ferrocenes, which suggested that decakis(acetox ymercurio)ferrocene was not completely decamercurated. Treatment of ru thenocene with mercuric acetate (10 equiv) in refluxing dichloroethane afforded decakis(acetoxymercurio)ruthenocene (88%). Reaction of decak is(acetoxymercurio)ruthenocene with cupric chloride dihydrate in aceto ne, potassium tribromide in water, or potassium triiodide in water aff orded decachlororuthenocene (73%), decabromoruthenocene (47%), and dec aiodoruthenocene (39%), respectively. Inspection of the H-1 NMR spectr a of crude decachlororuthenocene and decabromoruthenocene showed no re sonances that could be attributed to partially halogenated ruthenocene s, which indicates that decakis(acetoxymercurio)ruthenocene was greate r-than-or-equal-to 98% decamercurated. Treatment of pentamethylrutheno cene with mercuric acetate in 1:1 diethyl ether/ethanol afforded penta kis(acetoxymercurio)pentamethylruthenocene (88%). Pentakis(acetoxymerc urio)pentamethylruthenocene showed hindered rotation of the mercury-ac etate groups in the H-1 NMR spectra. Halogenation afforded pentachloro pentamethylruthenocene (67%), pentabromopentamethylruthenocene (35%), and pentaiodopentamethylruthenocene (60%). Treatment of methylcyclopen tadienyl)(eta5-indenyl)ruthenium(II) with mercuric acetate (greater-th an-or-equal-to 3 equiv) in 1:1 diethyl ether-ethanol afforded yl)(eta5 -pentamethylcyclopentadienyl)ruthenium(II) (99%), which could be bromi nated and iodinated to afford tribromoindenyl)(eta5-pentamethylcyclope ntadienyl) ruthenium(II) (29%) and triiodoindenyl)(eta5-pentamethylcyc lopentadienyl)r uthenium(II) (66%). The structure of triiodoindenyl)(e ta5-pentamethylcyclopentadienyl)r uthenium(II) was determined, showing that it crystallized in the monoclinic space group P2(1)/c with cell dimensions a 15.934(3) angstrom, b = 10.308(4) angstrom, c = 12.530 (5 ) angstrom, beta = 93.53(2)-degrees, V = 2054(1) angstrom3, and Z = 4.