First Bis(allenylidene)diruthenium Derivatives [(Ph3P)4(μ-Cl)3Ru2(CCCAr2)2]PF6 and Access to [(Ph2PCH2CH2PPh2)2ClRu(CCCAr2)]PF6 Complexes

RuCl2(PPh3)3 reacts with HC⋮CC(OH)Ar2 derivatives in the presence of NaPF6 to selectively afford only one isomer of the cationic bis(allenylidene) binuclear complexes [(Ph3P)4(μ-Cl)3Ru2(CCCAr2)2]PF6 [3; Ar = C6H5 (a), p-C6H4Cl (b), p-C6H4F (c)]. Complex 3a on treatment with an excess of Ph2PCH2CH2PPh2 (dppe) gives access to the new mononuclear complex trans-[(dppe)2ClRu(CCCAr2)]PF6 (4a). The direct reaction of cis-RuCl2(dppe)2 with the alcohols HC⋮CC(OH)Ar2 and NaPF6 also readily gives the allenylidene complexes 4a − c.