Organosulphur–transition-metal chemistry. Part 6. Reactions of cyclo-octatetraenyl and cycloheptatrienyl thioethers with metal carbonyls

Abstract

The compound C8H7SMe has been prepared by treating cyclo-octatetraenyl-lithium with MeSCl. Reaction with [Fe2(CO)9] provides tricarbonyliron complexes [Fe(CO)3(C8H7SMe)] and trans-[Fe2(CO)6(C8H7SMe)]; the former appears to undergo the characteristic oscillatory fluxional motion of such monosubstituted cyclo-octatetraene complexes, but the latter is non-fluxional. Sulphur–C8H7 bond cleavage is also evident, in the formation of [Fe2(CO)6(µ-SMe)2] and [Fe4(CO)12(µ4-S)(µ-SMe)2], and of bicyclo-octatetraenyl when C8H7SMe and [Ru3(CO)12] react. Similarly S–C7H7 bond cleavage is predominant in reactions of known C7H7SR-7 (R = Me or Ph) and new C7H7SBut-7 (from [C7H7][BF4] and Na[SBut]) with a variety of metal carbonyls. Only [Fe2(CO)6(µ-SR)2] is obtained with [Fe2(CO)9], and [Mo2(CO)2(µ-SBut)2(η-C5H5)2] with [Mo2(CO)6(η-C5H5)2], but from [Ru3(CO)12] complexes, [Ru3(CO)6(µ3-SBut){µ3-(η7-C7H7)}] and [Ru2(CO)4(µ-SR){µ-(η7-C7H7)}](R = Me or But) are isolated, containing the components of C7H7SR as separate ligands. Fluxional rotation of the C7H7 ring in the diruthenium complexes is slowed at –100 °C, shown by n.m.r. spectra which also reveal restricted rotation about the S–But bond.