The allenylidene complex [Ru(η5-C5H5)(CCCPh2)(CO)(PiPr3)]BF4 (1) reacts with diethylamine and piperidine to give the azoniabutadienyl derivatives [Ru(η5-C5H5){C(CHCPh2)NEt2}(CO)(PiPr3)]BF4 (2) and (3), respectively. The molecular structure of 2 has been determined by X-ray crystallography. The geometry around the ruthenium center is close to octahedral with the cyclopentadienyl ligand occupying three sites of a face. The Ru−Cα bond length is 2.063(6) Å, whereas the Cα−N distance is 1.306(7) Å. Treatment of 2 and 3 with sodium methoxide produces the deprotonation of the CHCPh2 fragment to afford the aminoallenyl derivatives Ru(η5-C5H5){C(NEt2)CCPh2}(CO)(PiPr3) (4) and (5). Complex 1 also reacts with n-propylamine and aniline. In this case, the reaction products are [Ru(η5-C5H5){C(CHCPh2)NHnPr}(CO)(PiPr3)]BF4 (6) and [Ru(η5-C5H5){C(CHCPh2)NHPh}(CO)(PiPr3)]BF4 (7). Treatment of 6 and 7 with sodium methoxide produces the deprotonation of the nitrogen atom of the unsaturated η1-carbon ligand, to give the azabutadienyl compounds Ru(η5-C5H5){C(CHCPh2)NnPr}(CO)(PiPr3) (8) and Ru(η5-C5H5){C(CHCPh2)NPh}(CO)(PiPr3) (9), respectively. The ellipticities of the Ru−Cα and Cα−N bonds of the model compounds [Ru(η5-C5H5){C(CHCH2)NH2}(CO)(PH3)]+ (10), Ru(η5-C5H5){C(NH2)CCH2}(CO)(PH3) (11), and Ru(η5-C5H5){C(CHCH2)NH}(CO)(PH3) (12) have been studied using the AIMPAC series of programs. The obtained values are 0.07 and 0.12 (10), 0.05 and 0.07 (11), and 0.07 and 0.10 (12), respectively.

The allenylidene complex [Ru(η5-C5H5)(CCCPh2)(CO)(PiPr3)]BF4 (1) reacts with 2-aminopyridine to give a mixture of the complexes [Ru(η5-C5H5){2,2-diphenyl-2H-pyridinium[1,2-a]pyrimidin-4-yl}(CO)(PiPr3)]BF4 (2) and (3). The molar ratio of the isomers in the mixture depends on the reaction temperature. At temperatures lower than −30 °C, isomer 2 is the main reaction product, while at 0 °C an inverse relationship is observed. The structure of 2 has been determined by an X-ray investigation, revealing a Ru−C(bicycle) distance of 2.08(1) Å. Treatment of 2 with sodium methoxide results in the deprotonation of the NH group of the heterocycle to give the pyrido[1,2-a]pyrimidinyl derivative Ru(η5-C5H5){2,2-diphenyl-2H-pyrido[1,2-a]pyrimidin-4-yl}(CO)(PiPr3) (4), which has been also characterized by an X-ray diffraction analysis. In this case, the study reveals a Ru−C(bicycle) distance of 2.097(5) Å. The deprotonation of 2 is reversible. Thus, the addition of HBF4·OEt2 to dichloromethane solutions of 4 regenerates 2. Similarly, the treatment of 4 with methyl trifluoromethanesulfonate affords [Ru(η5-C5H5){1-methyl-2,2-diphenyl-2H-pyridinium[1,2-a]pyrimidin-4-yl}(CO)(PiPr3)]CF3SO3 (5). Complex 1 also reacts with thioisonicotinamide. The reaction yields [Ru(η5-C5H5){4,4-diphenyl-2-(p-pyridinyl)-4H-1,3-thiazinium-6−yl}(CO)(PiPr3)]BF4 (6), which in the presence of sodium methoxide affords Ru(η5-C5H5){4,4-diphenyl-2-(p-pyridinyl)-4H-1,3-thiazin-6-yl}(CO)(PiPr3) (7). The structure of 7 has been determined by an X-ray investigation, revealing a Ru−C(cycle) distance of 2.067(4) Å. The deprotonation of 6 is also reversible. Thus, the addition of HBF4·OEt2 to dichloromethane solutions of 7 regenerates 6. Similarly, treatment of 7 with methyl trifluoromethanesulfonate gives [Ru(η5-C5H5){3-methyl-4,4-diphenyl-2-(p-pyridinyl)-4H-1,3-thiazinium-6-yl}(CO)(PiPr3)]CF3SO3 (8).