Phosphonioalkynyl indenylruthenium(II) complexes [Ru{C
CC(R)H(PR3)}(η5-C9H7)(PPh3)2][PF6] (R = Ph, PR3 = PMe3; R = H, PR3 = PPh3): suitable precursors of highly unsaturated σ-alkynyl and vinylidene derivatives
Abstract
Deprotonation of the phosphonioalkynyl ruthenium(II) complexes [Ru{CCC(R1)H(PR3)}(η5-C9H7)(PPh3)2][PF6] (R1 = Ph, PR3 = PMe3 1; R1 = H, PR3 = PPh3 2) with LiBun in THF at –20 °C gave the ylide alkynyl derivatives [Ru{C
CC(R1)
PR3}(η5-C9H7)(PPh3)2] (R1 = Ph, PR3 = PMe3 3; R1 = H, PR3 = PPh3 4), which react in situ with aldehydes or ketones via a Wittig process to afford the neutral σ-enynyl complexes [Ru{C
CC(R1)
CR2R3}(η5-C9H7)(PPh3)2] [R2R3 = CH2(CH2)3CH2, R1 = Ph 5a or H 6a; R2 = H, R3 = Me, R1 = Ph 5b or H 6b; R2 = R3 = R1 = Ph 5c]. Compounds 5b and 6b have been obtained as mixtures of the corresponding E and Z stereoisomers. Protonation of 5 and 6 with HBF4·Et2O in THF at –20 °C takes place selectively on the Cβ of the enynyl chain to yield the cationic vinylvinylidene derivatives [Ru{
C
C(H)C(R1)
CR2R3}(η5-C9H7)(PPh3)2][BF4] [R2R3 = CH2(CH2)3CH2, R1 = Ph 7a or H 8a; R2 = H, R3 = Me, R1 = Ph 7b or H 8b; R2 = R3 = R1 = Ph 7c]. The σ-polyenynyl complexes [Ru{C
CC(R1)
CH(CH
CH)nR2}(η5-C9H7)(PPh3)2] (n = 1, R2 = Ph, R1 = Ph 9a or H 10a; R2 = Prn, R1 = Ph 9b or H 10b; n = 2, R2 = Me, R1 = Ph 11 or H 12) have been obtained in high yields, as mixtures of the E and Z stereoisomers, by reaction of 3 and 4 with unsaturated aldehydes. Protonation of these derivatives yielded the highly unsaturated vinylidene complexes [Ru{
C
C(H)C(R1)
CH(CH
CH)nR2}(η5-C9H7)(PPh3)2][BF4] (n = 1, R2 = Ph, R1 = Ph 13a or H 14a; R2 = Prn, R1 = Ph 13b or H 14b; n = 2, R2 = Me, R1 = Ph 15 or H 16). The σ-ynenynyl and σ-keteniminyl complexes [Ru{C
CC(Ph)
CH(C
CPh)}(η5-C9H7)(PPh3)2] and [Ru{C
CC(Ph)
C
NPh}(η5-C9H7)(PPh3)2] have also been prepared by reaction of 3 with PhC
CCHO and phenyl isocyanate, respectively. The 1H, 31P-{1H} and 13C-{1H} NMR data for all the novel complexes are reported.