摘要:
The cluster Ir-3(CO)(3)(eta(5)-C9H7)(3) (1) reacts with (HBF4Et2O)-Et-. to form [Ir-3 mu-H)(CO)(3)(eta(5)-C9H7)(3)]-[BF4] (2). Deprotonation of 2 with NEt3 generates C-s-Ir-3(CO)(3)eta(5)-C9H7)(3) (1c), which rapidly reverts to an equilibrium mixture containing C-3nu-Ir-3(mu-CO)(3)(eta(5)-C9H7)(3) (1a) as the major isomer. Activation parameters for the reversion are DeltaH(double dagger) = 17.0(3) kcal mol(-1) and DeltaS(dagger) = -13(1) cal mol(-1) K-1, and K-eq = [1a]/[1c] = 16.7(7) at 25 degreesC. Variable-temperature NMR experiments indicate that 1c undergoes a dynamic process, with T-c = -30 degreesC and DeltaG(c)(double dagger) = 12.4(3) kcal mol(-1), which equilibrates the three indenyl ligands but does not equilibrate the two sets of CO ligands on opposite sides of the Ir-3 plane.