Synthetic applications of the reaction of silver(I) salts with the bis-[dicarbonyl(π-cyclopentadienyl)iron] complex

Abstract

In polar solvents the iron–iron bond of the dimeric complex [(cp)₂Fe₂(CO)₄](cp =π-cyclopentadienyl) is smoothly oxidised by Ag^I ions to give diamagnetic cations containing a co-ordinated solvent molecule, and metallic silver. Using acetone as solvent, the cation [(cp)Fe(CO)₂(acetone)]⁺ has been isolated and fully characterised as the hexafiuorophosphate salt. The use of Ag^I salts as convenient reagents for the synthesis of a wide variety of [(cp)Fe(CO)₂R][R = NO₃,CF₃CO₂,SCN,NCO,PhCO₂,p-Me-C₆ H₄SO₃ and OP(O)(OPh)₂], and[(cp)Fe(CO)₂L]⁺{L = CO, Ph₃P, Ph₃As, Ph₃Sb, MeCN, PhCH₂CN, Ph₂CHCN, PhSMe, and [(cp) Fe (CO)₂I]} complexes is described. Some mechanistic implications of the reaction are briefly discussed.