A series of carbonyl-, olefin-, alkyne-, hydrido-, and vinyliridium complexes containing bulky bifunctional phosphanes /Pr2PCH2X as ligands 1 curret

Article abstract of DOI:10.1002/cber.19971301107

Etheneiridium(I) complexes of the general composition trans[IrCl(C₂H₄)L₂L= iPr₂PCH₂CO₂Me (2a), JPr2PCH₂CO₂Et (2b), iPr₂P(CH₂)₃NMe₂ (2c) have been prepared either from IrClL₂ (3) or [IrCl(C₂H₄)22 (7) as starting materials. The corresponding carbonyl derivatives trans-[IrCl(CO)L₂] (6,10, 11) are obtained along similar routes. Photolysis of trans[IrCl(C₂H₄)L₂] (L = 2a, 2b) leads, by intramolecular C-H activation, to the formation of the octahedral hydrido(vinyl)iridium(III) compounds [IrHCl(CH=CH₂)(κ-L)κ²-L)] (16, 17), which are highly fluctional in solution. Carbonyl(hydrido) (vinyl) complexes are accessible either from 16 or 17 and CO, or from frans-[IrCl(C₂H₄)L₂] (L = 2a) and the propargylic alcohol HC=CCH(Ph)OH, respectively. Treatment of 3 or the corresponding dihydrido compound [IrH₂ClL₂] (4) with methyl vinyl ketone or methyl acrylate also yields hydrido(vinyl)iridi-um(III) complexes [IrHCl(CH=CHX)L₂] [X = C(=O)Me (18), C(=O)OMe (19)], in which instead of the C=O function of the phosphanyl ester the carbonyl group of the vinylic moiety is coordinated to the metal. The reaction of 16 (L = 2a) with terminal alkynes HC=CR (R = Ph, CO₂Me) affords the structurally related alkynyl(hydrido)iridium(III) compounds [IrHCl(C=CR)(κ-L)(κ²-L)] (28, 29), while from 16 and internal alkynes RCCR the iridium(I) complexes rans-[IrCl-(RCsCR)L₂] (30, 31) are obtained. Stepwise treatment of /rans-[IrCl(CO)L₂] (6: L = 2a) with (i) NaN(SiMe₃)₂, (U) H₂O, and (iii) HC1 leads, in the coordination sphere of the metal center, to a conversion of jPr₂PCH₂CO₂Me to iPr₂PCH₂CO₂H via the isolated phosphanylenolate and phosphanylacetate complexes 32 and 33 as intermediates. WILEY-VCH Verlag GmbH, 1997.