Hydrocarbon complexes of ruthenium. Part III. Reactions of cycloheptatrienes with ruthenium carbonyl
Abstract
Cycloheptatriene reacts with [Ru3(CO)12] in heptane to give as major product the cluster complex [Ru3(CO)6(C7H7)(C7H9)], together with the compounds [Ru(CO)3(C7H10)], [Ru(CO)3(C7H8)], [Ru(CO)2(C7H8)], and [Ru2(CO)6(C7H8)]. The complex [Ru3(CO)6(C7H7)(C7H9)], which contains both a cycloheptadienyl ligand and a bridging cycloheptatrienyl ring, reacts with iodine or CX4(X = Cl or Br) to give the compounds [Ru(X)(CO)2(C7H9)](X = Br or l) and [Ru2(X)(CO)4(C7H7)](X = Cl, Br, or l). Both [Ru3(CO)6(C7H7)(C7H9)] and [Ru2(X)(CO)4(C7H7)] contain C7H7 rings which are fluxional down to –100°C. Substituted cycloheptatrienes 7R-C7H7(R = Me or Ph) yield analogous complexes [Ru3(CO)6(C7H6R)(C7H8R)] with [Ru3(CO)12]. These in turn give [Ru(I)(CO)2(C7H8R)] and [Ru2(I)(CO)4(C7H6R)] with iodine. The latter are fluxional with n.m.r. spectra which are limiting at low temperatures; this, together with a knowledge of the ground-state molecular structure of [Ru2(I)(CO)4(C7H6Ph)], allows an understanding of the degenerate process involved.