Reactions of Ruthenium Complexes Containing Pentatetraenylidene Ligand.

Abstract

Two ruthenium acetylide complexes [Ru]-C≡C-C≡C-C(OR)(C3 H5 )2 (2, R=H and 2 a, R=CH3 ; [Ru]=Cp(PPh3 )2 Ru) each with two cyclopropyl rings were synthesized from TMS-C≡C-C≡C-C(OH)(C3 H5 )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 NH4 PF6 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 Ph3 CPF6 presumably afforded pentatetraenylidene complex {[Ru]=C=C=C=C=C(C3 H5 )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(C3 H5 )2 }[PF6 ] (11). Treatment of 11 with K2 CO3 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.