Oxidation of [M(#eta#-C_5H_5)_2], M = Cr, Fe or Co, by the new Bronsted acid H_2O .B(C_6F_5)_3 yielding the salts [M(#eta#-C_5H_5)_2]~+ A~-, where A~- = [(C_6F_5)_3B(μ-OH)B(C_6F_5)_3]~- or [(C_6F_5)_3BOH...H_2OB(C_6F_5)_3]~-

摘要

The Bronsted acids H_2O.B(C_6F_5)_3 have been synthesized. Reaction of neutral divalent metallocenes [M(#eta#-C_5H_5)_2], M = Cr, Fe or Co, with two equivalents of H_2O.B(C_6F_5)_3 2a resulted in metallocene oxidation and formation of salts containing [M(#eta#-C_5H_5)_2]~+ cations together with the hydroxoborate anion [HOB(C_6F_5)_3]~- which is hydrogen bonded to the second acid equivalent, namely [M(#eta#-C_5H_5)_2][(F_5C_6)_3~-BOH...H_2OB(C_6F_5)_3], M = Cr 3a, Fe 4a or Co 5a. Treatment of one equivalent of 2a and one equivalent of B(C_6F_5)_3 1 with [M(#eta#-C_5H_5)_2] yielded salts containing the same metallocene cations but now with μ-OH bridged anions, as in [M(#eta#-C_5H_5)_2][F_5C_6)_3], where M = Cr 3b or Co 5b. All products have been characterised by NMR spectroscopy, elemental analysis, and the single-crystal structures of 2a, 3a, 4a and 5a have been determined.