Activation of CO, Isocyanides, and Alkynes by Frustrated Lewis Pairs Based on Cp*M/N (M = Rh, Ir) Couples.

The complexes [CpM(κ,',″-)][SbF] (Cp = η-CMe; M = Rh, , Ir, ; = pyridinyl-amidine) display M/N transition metal frustrated Lewis pair reactivity toward a range of substrates containing triple bonds. Whereas the rhodium complex reacts with CO yielding compound [CpRh(CO)(κ,-)][SbF] (), which contains a terminal carbonyl and a carbamoyl group, the iridium complex generates compound [CpIr(κ,,'-)][SbF] (), which only features the carbamoyl group. Compounds and react with stoichiometric amounts of the isocyanides CNR (R = Cyclohexyl, -CH(OMe), CHSO(-Tolyl)) to give the corresponding 1,1-insertion complexes [CpM(κ,,'-)][SbF] (). Complexes containing inserted and coordinated isocyanide ligands of formula [CpM(CNR)(κ,-)][SbF] () are obtained upon treating and with excess of the corresponding isocyanide. Compound reacts with CNBu affording the adduct [CpIr(CNBu)(κ,'-)][SbF] () which contains a terminal CNBu ligand. Complex is protonated by HSbF to give [CpIr(CNBu)(κ,'-)][SbF] (). The terminal alkynes HC≡CR (R = Ph, COEt) react with and rendering the alkynyl complexes . Dimethyl acetylenedicarboxylate reacts with complex to give compound via the formal 1,2-addition of a basic nitrogen atom and the metal across the alkyne triple bond. The new complexes have been characterized by analytical, spectroscopic and X-ray diffraction (XRD) methods.