Reactions of Ruthenium Complexes Containing Pentatetraenylidene Ligand

Two ruthenium acetylide complexes [Ru]−C≡C−C≡C−C(OR)(C3H5)2 (2, R=H and 2 a, R=CH3; [Ru]=Cp(PPh3)2Ru) each with two cyclopropyl rings were synthesized from TMS−C≡C−C≡C−C(OH)(C3H5)2 (1; TMS=trimethylsilyl). Treatments of 2 and 2 a with allyl halide in the presence of KPF6 afforded the vinylidene complexes 3 and 3 a, respectively. When NH4PF6 was used, instead of KPF6, additional ring‐opening reaction took place on one of the three‐membered ring. Treatment of [Ru]Cl with 1,3‐butadiyne (6), bearing an epoxide ring, afforded acetylide complex 7 with a furyl ring. Treatment of 2 a with Ph3CPF6 presumably afforded pentatetraenylidene complex {[Ru]=C=C=C=C=C(C3H5)2}[PF6] (10), which was not isolated. Additions of various alcohols in a solution of 10 generated a number of disubstituted allenylidene complexes {[Ru]=C=C=C(OR)−C=C(C3H5)2}[PF6] (11). Treatment of 11 with K2CO3 afforded the acetylide complex 12 bearing a carbonyl group, characterized by single X‐ray diffraction analysis. Addition of a primary amine to 10 caused cleavage of the farthermost C=C bond and several allenylidene complexes {[Ru]=C=C=C(Me)(NHR)}[PF6] (18) were isolated. R‐u with diyne: Ruthenium acetylide complex 2 a has been synthesized using a 1,3‐butadiyne ligand. Further addition of trityl ion Ph3CPF6 presumably generated ruthenium pentatetraenylidene complex 10. Various nucleophilic reagents were used in a solution of the cumulene complex, and a number of different substituted allenylidene and acetylide complexes were obtained.