A SERIES OF CARBONYL-IRIDIUM, OLEFIN-IRIDIUM, ALKYNE-IRIDIUM, HYDRIDO-IRIDIUM, AND VINYLIRIDIUM COMPLEXES CONTAINING BULKY BIFUNCTIONAL PHOSPHANES IPR(2)PCH(2)X AS LIGANDS

Etheneiridium(I) complexes of the general composition trans-[IrCl(C2H4 )L-2] [L = iPr(2)PCH(2)CO(2)Me (2a), iPr(2)PCH(2)CO(2)Et (2b), iPr(2)P (CH2)(3)NMe2 (2c)] have been prepared either from [IrClL2] (3) or [IrC l(C2H4)(2)](2) (7) as starting materials. The corresponding carbonyl d erivatives trans-[IrCl(CO)L-2] (6, 10, 11) are obtained along similar routes. Photolysis of trans-[IrCl(C2H4)L-2] (L = 2a, 2b) leads, by int ramolecular C-H activation, to the formation of the octahedral hydrido (vinyl)iridium(III) compounds [IrHCl(CH=CH2)(kappa-L)(kappa(2)-L)] (16 , 17), which are highly fluctional in solution. Carbonyl(hydrido) (vin yl) complexes are accessible either from 16 or 17 and CO, or from tran s-[IrCl(C2H4)L-2] (L = 2a) and the propargylic alcohol HC=CCH(Ph)OH, r espectively. Treatment of 3 or the corresponding dihydrido compound [I rH2ClL2] (4) with methyl vinyl ketone or methyl acrylate also yields h ydrido(vinyl)iridium(III) complexes [IrHCl(CH=CHX)L-2] [X = C(=O)Me (1 8), C(=O)OMe (19)], in which instead of the C=O function of the phosph anyl 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)(kappa-L)(kappa(2)-L)] (28, 29), while from 16 and internal alkynes RC=CR the iridium(I) complexes trans-[IrCl(RC =CR)L-2] (30, 31) are obtained. Stepwise treatment of trans-[IrCl(CO)L -2] (6: L = 2a) with (i) NaN(SiMe3)(2), (ii) H2O, and (iii) HCl leads, in the coordination sphere of the metal center, to a conversion of iP r(2)PCH(2)CO(2)Me to iPr(2)PCH(2)CO(2)H via the isolated phosphanyleno late and phosphanylacetate complexes 32 and 33 as intermediates.