SYNTHESIS, CHARACTERIZATION, AND REACTIVITY OF TRANS-IR(PR(3))2(CO)(NHR'), WHERE R=ME AND ET AND R'=PH AND BU(T)

The synthesis and characterization of terminal Ir(I)-amido complexes containing trialkylphosphine ligands are described. The anilide complexes, trans-Ir(PR(3))(2)(CO)(NHPh), where PR(3) = PMe(3) (1) and PEt(3) (2), undergo insertion reactions with CO and subsequent C-H activation to produce Ir(PR(3))(2)(CO)(H)[C(O)NH(C6H4)], 5 and 6. The structure of these orthometallated products is similar to that found for the analogous PPh(3) complexes reported previously. It was also possible for the first time to synthesize an alkylamide complex, trans-Ir(PEt(3))(2)(CO)(NHBu(t)), 3, which was found to readily convert to an amido-bridged dimeric species [Ir(PEt(3))(CO)(mu-NHBu(t))](2), 4. A rapid reaction results between 3 and CO to produce a carbamoyl complex, Ir(PEt(3))(2)(CO)(2)[C(O)NHBu(t)], 7. A detailed spectroscopic study established the structure of 7 to be trigonal bipyramidal, with the carbamoyl ligand in an axial position and the phosphine ligands distributed between axial and equatorial positions. An alkyne adduct was formed between 3 and PhC=CPh, whereas PhC=CH produces a monoalkynyl complex. Addition of two or more equivalents of PhC=CH ultimately affords the bisalkynyl complex, trans-Ir(PEt(3))(2)(CO)(H)(-C=CPh)(2), 9.