Addition of Secondary and Primary Amines to the Allenylidene Ligand of [Ru(η5-C5H5)(CCCPh2)(CO)(PiPr3)]BF4: Synthesis of Azoniabutadienyl, Aminoallenyl, and Azabutadienyl Derivatives of Ruthenium(II)

Abstract

The allenylidene complex [Ru(η5-C5H5)(CCCPh2)(CO)(PiPr3)]BF4 (1) reacts with diethylamine and piperidine to give the azoniabutadienyl derivatives [Ru(η5-C5H5){C(CHCPh2)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 CHCPh2 fragment to afford the aminoallenyl derivatives Ru(η5-C5H5){C(NEt2)CCPh2}(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(CHCPh2)NHnPr}(CO)(PiPr3)]BF4 (6) and [Ru(η5-C5H5){C(CHCPh2)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(CHCPh2)NnPr}(CO)(PiPr3) (8) and Ru(η5-C5H5){C(CHCPh2)NPh}(CO)(PiPr3) (9), respectively. The ellipticities of the Ru−Cα and Cα−N bonds of the model compounds [Ru(η5-C5H5){C(CHCH2)NH2}(CO)(PH3)]+ (10), Ru(η5-C5H5){C(NH2)CCH2}(CO)(PH3) (11), and Ru(η5-C5H5){C(CHCH2)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.