Vinyliden-Uebergangsmetallkomplexe VIII. Die stufenweise Umwandlung von Alkiniridium(I)- in Alkinyl(hydrido)iridium(III)- und Vinylideniridium(I)-Komplexe

Article abstract of DOI:10.1016/0022-328X(90)85231-M

Square-planar vinylidene iridium(I) complexes trans-i3)2> (XIa-c) have been prepared in two steps from trans-i3)2> (VIIIa-c) via the isolated (for R=Me, Ph) alkynyl(hydrido) iridium(III) isomers i3)2> (IXb, c).The reaction of 2 and PPrⁱ3 with HCCSiPh3 leads directly to the formation of i3)2> (IXe).The vinylidene complexes XIa-c react with HBF4 to give first i3)2>⁺ (XIIa-c) and then by intramolecular rearrangement to give the BF4 salts of the carbyne iridium cations trans-⁺ (XIIIa-c).In solution, an equilibrium exists between XIIIa-c and XIIa-c which lies almost exclusively towards XIIIa-c.Treatment of XIIIa-c with NaH in benzene regenerates the vinylidene iridium compounds XIa-c.The hydroxo, iodo and methyl derivatives, trans-i3)2> (X= OH: XVa-c; X= I: XVIa-c; X= CH3: XVIIa, c), are prepared from XIa-c by ligand displacement using KOH, NaI and LiCH3 as reagents. trans-i3)2> (XVIa) reacts with CO to give the octahedral alkynyl(hydrido)iridium(III) complex i3)2(CO)> (XVIII).From XIc and XIa as starting materials, the vinyl iridium(III) compounds i3)2(CO)> (XIX) and i3)2> (XX) have also been obtained.