PI-OLEFIN IRIDIUM COMPLEXES .22. C-H ACTI VATION OF AROMATIC AND ALIPHATIC SOLVENT MOLECULES RH IN THE REACTION OF [CP-ASTERISK-IRCL2](2) WITH BUTADIENEMAGNESIUM WITH FORMATION OF [CP-ASTERISK-IR(ETA(3)-C4H7)R], AND CRYSTAL-STRUCTURE OF [CP-ASTERISK-IR(ETA(3)-C4H7)C6H5]

Reactions of [CpIrCl2](2) (Cp* = eta(5)-C(5)Me(5)) with [MgC4H6.2 THF ](n) at low temperature give [CpIr(eta(4)-C4H6)] together with [Cp*Ir (eta(3)-C4H7)R] compounds, the latter being formed via C-H activation of solvent molecules RH (RH = benzene, toluene, anisole, thiophene, fu rane, N-methylpyrrole, pentane, cyclohexane, THF). In the case of pyrr ole, C-N-activation occurs. The ratio of syn and anti isomers of the 1 -methylallyl complexes as well as the sites of C-H activation of RH we re investigated by NMR spectrometry. An enantiomorphous crystal of [CP Ir(eta(3)-C4H7)C6H5] was characterized by X-ray diffraction analysis which reveals trigonal planar coordination at the Ir atom and an exo, syn conformation of the 1-methylallyl ligand. A mechanism of the react ion which involves 16-electron intermediates is discussed. The corresp onding system [CpRhCl2](2)/butadienemagnesium/RH gives only [Cp*Rh(et a(4)-C4H6)], and no C-H activation is observed.