Reaction of the RuTp(PR3)Cl fragment with alkynols: Formation of carbene, vinylidene, allenylidene, and carbyne complexes

The reaction of RuTp(COD)Cl (1) with PR3 (PR3 = PPh2iPr, PiPr3, PPh3) and propargylic alcohols HCCCPh2OH, HCCCFc2OH (Fc = ferrocenyl), and HCCC(Ph)MeOH has been studied.In the case of PR3 = PPh2iPr, PiPr3 and HCCCPh2OH, the 3-hydroxyvinylidene complexes RuTp(PPh2iPr)(CCHC(Ph)2OH)Cl (2a) and RuTp(PiPr3)(CCHC(Ph2)OH)Cl (2b) were isolated.With PR3 = PPh2iPr and HCCCFc2OH as well as with PR3 = PPh3 and HCCCPh2OH dehydration takes place affording the allenylidene complexes RuTp(PPh2iPr)(CCCFc2)Cl (3b) and RuTp(PPh3)(CCCPh2)Cl (3c).Similarly, with PPh2iPr and HCCC(Ph)MeOH rapid elimination of water results in the formation of the vinylvinylidene complex RuTp(PPh2iPr)(CCHC(Ph)CH2)Cl (4).In contrast to the reactions of the RuTp(PR3)Cl fragment with propargylic alcohols, with HCC(CH2)nOH (n = 2, 3, 4, 5) six-, and seven-membered cyclic oxycarbene complexes RuTp(PR3)(C4H6O)Cl (5), RuTp(PR3)(C5H8O)Cl (6), and RuTp(PR3)(C6H10O)Cl (7) are obtained. On the other hand, with 1-ethynylcyclohexanol the vinylvinylidene complex RuTp(PPh2iPr)(CCHC6H9)Cl (8) is formed. The reaction of the allenylidene complexes 3a–c with acid has been investigated. Addition of CF3COOH to a solution of 3a–c resulted in the reversible formation of the novel RuTp vinylcarbyne complexes [RuTp(PPh2iPr)(C–CHCPh2)Cl]+ (9a), [RuTp(PPh2iPr)(C–CHCFc2)Cl]+ (9b), and [RuTp(PPh3)(C–CHCPh2)Cl]+ (9c). The structures of 3a, 3b, and 5b have been determined by X-ray crystallography.

Graphical abstractThe reaction of RuTp(COD)Cl with PR3 = PPh2iPr, PiPr3, PPh3 and alkynols HCCCR2′OH affords neutral allenylidene complexes RuTp(PR3)(CCCR2′)Cl.Addition of acid to a solution of these complexes leads to reversible formation of novel carbyne complexes of the type [RuTp(PR3)(C–CHCR2)Cl]+.Figure optionsDownload full-size imageDownload as PowerPoint slide