Indenyl Ruthenium Research Articles

Synthesis of phosphine‐tethered indenyl ruthenium complexes through c‐h bonds activation followed by C‐C bond coupling: High performance catalysts for the redox isomerization of allylic alcohols

Reactions of 3‐(2‐pyridyl)indene and 5‐methyl‐3‐(2‐pyridyl)indene with Ru(PPh3)3Cl2, generated two phosphine‐tethered indenyl ruthenium complexes {η5,κ1P‐(C5H4N‐C9H4R‐C6H4PPh2)}RuCl(PPh3) (R = H, 1; R = CH3, 2), respectively. While treatment of 3‐(6‐methyl‐2‐pyridyl)indene with Ru(PPh3)3Cl2 gave a product {η5‐(CH3C5H3N‐C9H6)}RuCl(PPh3)2 (3); 1 could further react with NaBArF4 to produce a cationic complex [{η5,κ1P‐(C5H4N‐C9H5‐C6H4PPh2)}Ru(PPh3)][BArF4] (15). When treated with NaOMe in methanol, 1 was converted into [{η5,κ1P‐(C5H4N‐C9H5‐C6H4PPh2)}RuH(PPh3)] (16). These five complexes were investigated as catalysts for redox isomerization of allylic alcohols, and 16 exhibited best catalytic activity in the presence of tBuOK, reaching quantitative yield in 5 min when α‐vinylbenzyl alcohol was used as the substrate, requiring catalyst loading of 1 mol%.

Cyclopentadienyl and indenyl ruthenium(II) complexes containing diazafluorenone derivative ligands: Syntheses, characterization, antibacterial and cytotoxicity studies

We have successfully synthesized a series of eight versatile, half-sandwich ruthenium(II) cationic complexes [(Cp/Ind)Ru(к2(N∩N)L)(PPh3)]PF6 (1–8), where L represents a 4,5-diazafluorenone derivative ligand. These complexes were isolated as their hexafluorophosphate salts and subjected to thorough characterization using various spectroscopic techniques such as FT-IR, NMR, UV and Mass. Furthermore, single-crystal X-ray diffraction studies determined the molecular structures of representative complexes 1, 7, and 8. We screened the synthesized complexes and ligands in vitro to assess their potential antibacterial activity against three bacterial strains: the Gram-positive Staphylococcus aureus, the Gram-negative Escherichia coli and Klebsiella pneumoniae. Remarkably, all the compounds exhibited potent antibacterial activity against the tested organisms. In addition, we conducted a cell viability assessment to evaluate the cytotoxicity of the free ligands. The results indicated that the ligands did not demonstrate statistically significant cytotoxicity. However, it is noteworthy that complex 1 displayed more pronounced cytotoxic effects on the DL cell line, followed by complexes 3, 5, and 7.

Cyclopentadienyl and indenyl ruthenium(II) complexes containing pyridyl/pyrimidyl based thiourea derivative ligands: Syntheses, antibacterial and antioxidant studies

A series of cationic complexes [(Cp/Ind)Ru(к2(NS)-L)(PPh3)]PF6 (1–8) were synthesized by the reaction of [CpRu(PPh3)2Cl] or [(Ind)Ru(PPh3)2Cl] (Cp=η5-C5H5, Ind=η5-C9H7) with respective pyridyl/pyrimidyl thiourea derivatives 1-phenyl-3-(pyridin-2-yl)thiourea (L1), 1-phenyl-3-(pyrazin-2-yl)thiourea (L2), 1-(4-methylpyridin-2-yl)-3-phenylthiourea (L3) and 1-benzyl-3-(pyridin-2-yl)thiourea (L4). The complexes have been fully characterized by IR, UV–Vis, NMR and ESI-MS spectral methods. The molecular structures of complexes 1 and 3 were established by single-crystal X-ray diffraction studies. Furthermore, the complexes (1–8) and the ligands were screened for radical scavenging activity and pathogenic bacteria such as S. aureus, E. coli and K. pneumoniae.

Cp and indenyl ruthenium complexes containing dithione derivatives: Synthesis, antibacterial and antifungal study

A series of cationic complexes [(Cp/Ind)Ru(к2(SS)-L)(PPh3)]PF6 (1–6) are obtained by the reaction of [CpRu(PPh3)2Cl] or [(Ind)Ru(PPh3)2Cl] (Cp = η5-C5H5, Ind = η5-C9H7) with respective dithione derivatives 1,2-di(piperidin-1-yl)ethane-1,2-dithione (L1), 1,2-dimorpholinoethane-1,2-dithione (L2) and 1,2-dithiomorpholinoethane-1,2-dithione (L3). All the compounds are characterized using spectroscopic techniques. The molecular structures of complexes 1, 2 and 4 are established by single-crystal X-ray diffraction studies. Antimicrobial studies were tested against three strains of bacterial microorganisms Staphylococcus aureus (gram + ve), Bacillus subtilis (gram + ve), Klebsiella pneumoniae (gram -ve) and one strain of fungal microorganism Candida albicans.

Indenyl Ruthenium Complexes with an Unusual η3 Coordination Mode

Dinuclear indenyl ruthenium complexes were prepared and characterized using X-ray crystallography. Their crystal structures revealed the first examples of indenyl complexes containing an unusual η3 coordination mode with bonding through the junction carbon and the adjacent carbons of the five- and six-membered rings of the indenyl ligand.

1,4-Bis(diphenylphosphanyl)butane-κ2P,P′]chlorido(η5-indenyl)ruthenium(II)

Facile ligand substitution is observed when the ruthenium chloride complex [Ru(η5-C9H7)Cl(PPh3)2] is treated with 1,4-bis­(diphenyl­phosphan­yl)butane in refluxing toluene yielding the title compound, [Ru(C9H7)Cl(C28H28P2)]. The RuII atom has a typical piano-stool coordination, defined by the indenyl ligand, one Cl atom and two phosphanyl P atoms. The Ru—P bond lengths are 2.2502 (9) and 2.2968 (8) Å.

Pyridyl-Substituted Indenyl Ruthenium Complexes: Synthesis, Structures, and Reactivities

We have investigated the synthesis of a novel pyridyl-substituted indenyl trinuclear ruthenium complex, {μ2-η5:η1-(C5H4N)(C9H5)}Ru3(CO)9 (1), and its reactivities with pyridine derivatives, PPh3, and different types of alkenes. Complex 1 was synthesized in 89% yield from Ru3(CO)12 and 3-(2-pyridyl)indene (1:1 mol ratio) in refluxing heptane. The reaction of 1 with a 5-fold excess of 3-(2-pyridyl)indene gave two complexes, {η1-(C5H4N)(C9H6)}2Ru(CO)2 (2) and {η5-(C5H4N)(C9H6)}{η1-(C5H4N)(C9H6)}Ru2(CO)4 (3). Both were also converted back to 1 in the presence of an equimolar amount of Ru3(CO)12, although the yields were low. Reaction of 1 in refluxing toluene afforded an unexpected complex, {μ3-η6:η3:η1-(C5H4N)(C9H5)}Ru3(CO)7 (4), via the loss of two CO groups. Complex 4 represents a completely new type of coordination mode (μ3-η6:η3:η1) of indenyl ligands in transition metal complexes. The reactions of 1 with 2-(2-pyridyl)indene, 1,2,3,5-tetramethyl-4-(2-pyridyl)cyclopentadiene, 1,2-diphenyl-4-(2-pyridyl)cyc...

Diels−Alder Reactions of Benzyne with Indenyl and Fluorenyl Ruthenium Complexes

The indenyl ruthenium compound (η5-C9H7)Ru(η5-C5Me5) (1) was found to react with benzyne, generated from o-trimethylsiylphenyl triflate by fluoride-induced 1,2-elimination, to afford the Diels−Alder adduct 1,2-(1,4-dihydronaphthalen-1,4-diyl)pentamethylruthenocene (2). When the bis(indenyl) ruthenium complex (η5-C9H7)2Ru (3) reacted with benzyne, the bisadduct 4 was obtained along with the monoadduct 5. Reaction of fluorenyl ruthenium compound (η5-C13H9)Ru(η5-C9H7) (6) with benzyne gave only the monoadduct 7 and a byproduct, 9,9′-diphenylfluorene (8). The crystal structures of 7 and 8 were determined by X-ray diffraction analysis.

Rate Studies on the Release of Terminal Alkynes from Indenylruthenium(II) Vinylidene Complexes. Implications on the Mechanism of η1-Vinylidene into η2-Alkyne Isomerization

The indenylruthenium(II) vinylidene complexes [Ru{═C═C(H)R}(η5-C9H7)(PPh3)2][PF6] [R = Ph (1), 4-MeOC6H4 (2), 4-MeC6H4 (3), 4-PhC6H4 (4), 4-FC6H4 (5), 4-ClC6H4 (6), 4-IC6H4 (7), 4-MeCOC6H4 (8), 4-O2NC6H4 (9), nBu (10), (η5-C5H4)Fe(η5-C5H5) (11, Fc)] have been synthesized from [RuCl(η5-C9H7)(PPh3)2] and RC≡CH, in a methanolic solution of NaPF6 at room temperature. The complexes, when dissolved in acetonitrile-d3, release the vinylidene ligand upon thermal activation in the form of the corresponding terminal alkyne, with formation of the solvato complex [Ru(N≡CCD3)(η5-C9H7)(PPh3)2][PF6] (1a). The reactions, followed by 31P{1H} NMR spectroscopy, exhibit first-order behavior in the vinylidene substrates, and the activation parameters ΔH⧧ = 24 ± 1 kcal mol−1 and ΔS⧧ = −3 ± 2 cal mol−1 K−1 for complex 1 (36−54 °C). The Hammett plot derived from the aryl-substituted complexes yields the reaction parameter ρ = −1.5, indicating a rate enhancement effect by electron-donor substituents on the β-C atom. Formation of ...

Indenyl complexes of ruthenium containing thiolate ligands. Structure of IndRu(dppe)SPh

The indenyl ruthenium thiolate complexes IndRu(PPh3)2SR, (1) [Ind = η5-C9H7; R = Prn (a), Ph (b), CH2Ph(c)] were prepared directly by reacting the thiolate anions (RS−) with IndRu(PPh3)2Cl. The one-pot reaction of IndRu(PPh3)2Cl, thiolate anions and dppa ligands gave IndRu(dppa)SR [dppa= bis(diphenylphosphino)ethane: dppe (2); bis(diphenylphosphino)methane: dppm (3)]. Complexes (1) readily react with NOBF4 in THF at room temperature to give [IndRu(PPh3)(NO)SR]BF4, (4). Complexes (1)–(4) have been characterized by spectroscopic techniques (i.r.,1H-n.m.r., 31P-n.m.r.) and by elemental analysis. The crystal structure of IndRu(dppe)SC6H5, (2b) has been determined by X-ray analysis.

Synthesis of indenyl ruthenium triazolato complexes by [3 + 2] cycloaddition of activated nitrile and alkynes to indenyl ruthenium azido complexes: crystal structures of [( η 5-C9H7)Ru(PMe2Ph)2{N3C2(CO2Me)2}] and [( η 5-C9H7)Ru(dppe){N3C2H(CN}

The indenyl ruthenium(II) azide complexes [(η5-C9H7)Ru(L2)N3], L2 = (PMe2Ph)2 (1), dppe (2) and dppm (3), (where dppe = Ph2PCH2CH2PPh2 and dppm = PPh2CH2PPh2) were readily prepared by the reaction of NaN3 with corresponding chloro complexes [(η5-C9H7)Ru(L2)Cl]. The azido complexes undergo [3 + 2] dipolar cycloaddition reactions with activated alkynes and nitrile (NCCH = CHCN) to yield new indenyl ruthenium triazolato complexes [(η5-C9H7)Ru(L2)(N3C2(CO2R)2)], L2 = (PMe2Ph)2, R = Me (4), Et (5); L2 = dppe, R = Et (6), L2 = dppm, R = Et (7) and [(η5-C9H7)Ru(L2)(N3C2HCN)], L2 = (PMe2Ph)2 (8), L2 = dppe (9), L2 = dppm (10). The complexes were fully characterized on the basis of microanalyses, IR and NMR spectroscopy. The structures of representative complexes 4 and 9 have been determined by single-crystal X-ray methods.

Half‐Sandwich η5‐Indenyl‐ and η6‐Areneruthenium(II) Complexes Bearing the Chiral Ligand (4S)‐2‐[(Sp)‐2‐(Diphenylphosphanyl)ferrocenyl]‐4‐(methylethyl)oxazoline (FcPN)

AbstractChiral indenylruthenium(II) [Ru(η5‐C9H7){κ2(P,N)‐FcPN}(PPh3)][PF6] (1), [Ru(η5‐C9H7)Cl{κ2(P,N)‐FcPN}] (2) and areneruthenium(II) [RuX(η6‐arene){κ2(P,N)‐FcPN}][PF6] [η6‐arene = p‐cymene, X = Cl (6a), H (7), N3 (8); η6‐arene = 1,2,3,4‐tetramethylbenzene, X = Cl (6b)] complexes containing the chiral ligand (4S)‐2‐[(SP)‐2‐(diphenylphosphanyl)ferrocenyl]‐4‐(methylethyl)oxazoline (FcPN) have been synthesised diastereoselectively. Reaction of 2 with terminal alkynes allows the synthesis of alkynyl [Ru(η5‐C9H7)(C≡CR){κ2(P,N)‐FcPN}] [R = Ph (3a), p‐CH3C6H4 (3b)], allenylidene [Ru(η5‐C9H7){κ2(P,N)‐FcPN}(=C=C=CPh2)][PF6] (4) and Fischer‐type carbene [Ru(η5‐C9H7){κ2(P,N)‐FcPN}{=C(OMe)CH=CHPh}][PF6] (5) complexes. The structures of complexes 2, 3a and 6a have been determined by X‐ray diffraction methods. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

Constrained coordination through atropisomerism: Synthesis and structure of an η 5:κ N-bidentate N, N-dimethylaniline-functionalised indenylruthenium(II) complex

Reaction of 1-(2- N, N-dimethylaminophenyl)-2-methylindenyllithium with (Ph 3P) 3RuCl 2 affords the chloro(indenyl)bis(triphenylphosphine)ruthenium(II) complex 5, where the nitrogen is not coordinated to the metal. The corresponding reaction of 1-(2- N, N-dimethylamino-6-methylphenyl)-2-methylindenyllithium affords the chloro(η 5:κ N-indenyl)(triphenylphosphine)ruthenium(II) complex 6, which has been characterised by single crystal X-ray analysis.

Indenylruthenium(II) Aminoallenylidenes: New Building Blocks for the Synthesis of Highly Unsaturated Alkynyl and Allenylidene Complexes

The allenylidene complexes [Ru(=C=C=CRPh)(η 5 -C 9 H 7 )(PPh 3 ) 2 ][PF 6 ] (R = Ph (1); R = H (2)) react with the ynamines R'C≡CNEt 2 (R' = Me, SiMe 3 ), yielding the aminoallenylidenes [Ru{=C=C=C(NEt 2 )[C(R')=C(R)Ph](η 5 -C 9 H 7 )(PPh 3 ) 2 ][PF 6 ] (R = Ph, R' = Me (3); R = H, R' = Me (4); R = Ph, R' = SiMe 3 (5)). The reactions proceed regio- and stereoselectively, the insertion of the ynamine taking place exclusively at the C β =C γ bond of the unsaturated chain. The analogous allenylidene complex 6 (R' = H, R = Ph) is obtained by desylilation of complex 5 with KF. The treatment of complex 3 with HBF 4 leads to the formation of the dicationic vinylidene [Ru{=C=C(H)C(=NEt 2 )[C(Me)=CPh 2 ]}(η 5 -C 9 H 7 )(PPh 3 ) 2 ] 2 + (7). The aminoallenylidene complex 3 undergoes regioselective nucleophilic additions of acetylides and other carbanions at the Cy atom, yielding (i) the disubstituted alkynylalkenylallen-ylidenes [Ru{=C=C=C(C≡CR)[C(Me)=CPh 2 ]}(η 5 -C 9 H 7 )(PPh 3 ) 2 ][BF 4 ] (R = Ph (8), SiMe 3 (9)) from the addition of acetylides LiC=CR, (ii) the 3-alkenyl-3,4,5-hexatrien-1-ynyl derivatives [Ru{C≡CC(=C=C=CRR')[C(Me)=CPh 2 ]}(η 5 -C 9 H 7 )(PPh 3 ) 2 ] (R = R' = Me (10); R = Ph, R' = H (11)) from the reaction with LiC=CCHRR', and (iii) the 3-alkenyl-3-buten-1-ynyl species [Ru{C≡CC(=CHR)[C(Me)=CPh 2 ]}(η 5 -C 9 H 7 )(PPh 3 ) 2 ] (R = H (12), R = n-Pr (13)) and the 3-alkenyl-3,5-hexadien-1-ynyl complex [Ru{C≡CC(=CHCH=CH 2 )[C(Me)=CPh 2 ]}(η 5 -C 9 H 7 )-(PPh 3 ) 2 ] (14) from the treatment with LiCH 2 R (R = H, n-Pr) and BrMgCH 2 CH=CH 2 , respectively. The secondary allenylidenes [Ru{=C=C=C(H)[C(R)=CPh 2 ]}(η 5 -C 9 H 7 )(PPh 3 ) 2 ]-[PF 6 ] (R = Me (16), R = H (17)) are obtained in a one-pot synthesis from the reactions of aminoallenylidenes 3 and 6 with LiBHEt 3 and subsequent treatment with silica, respectively. Highly unsaturated alkenylaminoallenylidenes of the general formula [Ru{=C=C=C(NEt 2 )-[(CR=CH) n C(Me)=CPh 2 ]}(η 5 -C 9 H 7 )(PPh 3 ) 2 ][PF 6 ] (n = 1, R = Me (18), R = SiMe 3 (19); n = 2, R = Me (22)) have been synthesized by regio- and stereoselective sequential insertion of one or two ynamines RC≡CNEt 2 (R = Me, SiMe 3 ) into the C β =C γ bond of the cumulene group of complexes [Ru{=C=C=C(H)[C(Me)=CPh 2 ]}(η 5 -C 9 H 7 )(PPh 3 ) 2 ][PF 6 ] (16) and [Ru{= C=C=C(H)[(CMe=CH)C(Me)=CPh 2 ]}(η 5 -C 9 H 7 )(PPh 3 ) 2 ][PF 6 ] (21), respectively. Structures of complexes 3 and 18 have been confirmed by X-ray crystallography.

In Search of Asymmetric Propargylic Substitution Reactions Mediated by Optically Active Indenyl‐ruthenium(II) Allenylidene Complexes

AbstractFor Abstract see ChemInform Abstract in Full Text.

Syntheses and characterization of indenylruthenium(II) complexes containing N, N′ donor Schiff base ligands. Molecular structures of [( η5-C 9H 7)Ru(PPh 3) 2(CH 3CN)]BF 4 and [( η5-C 9H 7)Ru(PPh 3)(C 5H 4–N-2–CHN–C 6H 4- p-CH 3)]BF 4

Reaction of the complex [( η 5-C 9H 7)Ru(PPh 3) 2Cl] ( 1) with acetonitrile in the presence of NH 4BF 4 leads to formation of the complex [( η 5-C 9H 7)Ru(PPh 3) 2(CH 3CN)]BF 4 ( 2). The complex ( 2) undergoes reactions with a series of N, N ′ donor Schiff bases, viz., para-substituted N-(pyrid-2-ylmethylene)-phenylamines (ppa) in methanol yielding indenyl ruthenium(II) Schiff base complexes of formulation [( η 5-C 9H 7)Ru(PPh 3)(C 5H 4N-2–CHN–C 6H 4- p-X)]BF 4 ( 3a– 3e), where C 9H 7=indenyl, X=H ( 3a), Me ( 3b), OMe ( 3c), NO 2 ( 3d), and Cl ( 3e), respectively. These complexes were fully characterized on the basis of elemental analyses and NMR spectroscopy. The molecular structures of the starting complex [( η 5-C 9H 7)Ru(PPh 3) 2(CH 3CN)]BF 4 ( 2) and a representative complex [( η 5-C 9H 7)Ru(PPh 3)(C 5H 4N–CHN–C 6H 4- p-CH 3)]BF 4 ( 3b) have been established by X-ray diffraction study.

Bond Activation by Electron Transfer in Indenyl Ruthenium(II) Complexes. The Electrochemical Reduction of [Ru(η5-C9H7)Cl(L)2] and [Ru(η5-C9H7)(L)2]+, L2= COD, L = PPh3

The reduction of half-sandwich indenyl complexes of general formula [Ru(η5-C9H7)Cl(L)2] (L = PPh3, 1; L2 = 1,5-cyclooctadiene, 2) and [Ru(η5-C9H7)(L)2]+ has been carried out in order to investigate...

Synthesis of indenyl-ruthenium(II) σ-alkynyl complexes via nucleophilic addition of (1 R)-(+)- and (1 S)-(−)-camphor enolates on the allenylidene group of [Ru(CCCPh 2)(η 5-C 9H 7)(PPh 3) 2][PF 6]: Efficient synthesis of novel optically pure vinylidene derivatives

The diphenylallenylidene complex [Ru(CCCPh 2)(η 5-C 9H 7)(PPh 3) 2][PF 6] ( 1) regioselectively reacts at the C γ atom with the lithium enolate derived from (1 R)-(+)-camphor to yield σ-alkynyl derivative [Ru{CCCPh 2(C 10H 15O)}(η 5-C 9H 7)(PPh 3) 2] ( 2). Complex 2 was obtained as a non-separable mixture of two diastereoisomers, i.e. (1 R,3 S,4 R)- 2 and (1 R,3 R,4 R)- 2 (ca. 3:2 ratio), in which the alkynyl fragment is located in exo or endo disposition on the camphor skeleton, respectively. Protonation of this mixture with HBF 4·Et 2O affords the vinylidene derivative [Ru{CC(H)CPh 2(C 10H 15O)}(η 5-C 9H 7)(PPh 3) 2][BF 4] ( 3) as a single diastereoisomer, i.e. (1 R,3 S,4 R)- 3, showing an exo disposition of the vinylidene group. The structure of complex (1 R,3 S,4 R)- 3 has been confirmed by X-ray diffraction. The molecular structure shows the typical pseudo-octahedral three-legged piano-stool geometry around the ruthenium atom, which is linked to the phosphorus atoms of the PPh 3 ligands, to the η 5-bonded indenyl ligand, and to an almost linear vinylidene chain (RuC(1)C(2)=165.6 (18)°) with a RuC(1) bond length of 1.88 (2) Å. Demetalation of (1 R,3 S,4 R)- 3, by treatment with acetonitrile at reflux, yields the terminal alkyne HCCCPh 2(C 10H 15O) ( 4) and the nitrile complex [Ru(NCMe)(η 5-C 9H 7)(PPh 3) 2][BF 4] ( 5). Compound 4 was obtained as a non-separable mixture of two diastereoisomers, i.e. (1 R,3 S,4 R)- 4 and (1 R,3 R,4 R)- 4 (ca. 3:1 ratio). Related reactions starting from diphenylallenylidene 1 and the (1 S)-(−)-camphor enolate are also reported.

Indenyl–ruthenium(ii) allenylidene complexes containing terpenic substituents as precursors of optically active terminal alkynes: scope and limitations

The optically active allenylidene complex [Ru{CCC(C9H16)}(η5-C9H7)(PPh3)2][PF6] (C(C9H16) = (1R,4S)-1,3,3-trimethyl-bicyclo[2.2.1]hept-2-ylidene) 1 regio- and stereoselectively reacts with unhindered anionic nucleophiles to yield the neutral σ-alkynyl derivatives [Ru{CCC(C9H16)R}(η5-C9H7)(PPh3)2] (R = H 2a, CN 2b, Me 2c, CCPh 2d). Protonation of 2a–d with HBF4·Et2O affords the cationic vinylidene complexes [Ru{CC(H)C(C9H16)R}(η5-C9H7)(PPh3)2][BF4] 3a–d, which can be easily demetalated, by treatment with acetonitrile, yielding the corresponding chiral acetylenic compounds HCC(C9H16)R 4a–d. The novel optically active indenyl–ruthenium(II) allenylidene complexes [Ru{CCC(C9H16)}(η5-C9H7)(PPh3)2][PF6] (C(C9H16) = (1R,4R)-1,7,7-trimethyl-bicyclo[2.2.1]hept-2-ylidene) 9 and [Ru{CCC(C9H14)}(η5-C9H7)(PPh3)2][PF6] (C(C9H14) = (1S,5S)-4,6,6-trimethyl-bicyclo[3.1.1]hept-3-en-2-ylidene) 10 have been prepared by activation of propargylic alcohols derived from the natural ketones (+)-camphor and (−)-verbenone, respectively, with [RuCl(η5-C9H7)(PPh3)2] 6. Treatment of 9 with anionic nucleophiles generates the neutral σ-enynyl complex [Ru{CCC(C9H15)}(η5-C9H7)(PPh3)2] 11 (C(C9H15) = (1R,4R)-1,7,7-trimethyl-bicyclo[2.2.1]hept-2-en-2-yl).

Easy Entry to Terminal 1,5- and 1,6-Enynes from (Indenyl)ruthenium(II) Allenylidenes and Grignard Reagents

The allenylidene complexes [Ru(CCCR1R2)(η5-C9H7)(PPh3)2][PF6] (R1 = R2 = Ph (1a); R1 = H, R2 = Ph (1b), C(Me)CPh2 (1c); CR1R2 = (1R)-1,3,3-trimethylbicyclo[2.2.1]hept-2-ylidene (1d)) react with Grignard reagents CH2CH(CH2)nMgBr (n = 1, 2) to yield the σ-alkynyl derivatives [Ru{C⋮CCR1R2(CH2)nCHCH2}(η5-C9H7)(PPh3)2] (2a−d, 3a−c). Protonation of 2a−d and 3a−c with HBF4·Et2O leads to the vinylidene complexes [Ru{CC(H)CR1R2(CH2)nCHCH2}(η5-C9H7)(PPh3)2][BF4] (4a−d and 5a−c), which can be easily demetalated with acetonitrile to afford the terminal enynes HC⋮CCR1R2(CH2)nCHCH2 (6a−d and 7a−c) and the nitrile complex [Ru(N⋮CMe)(η5-C9H7)(PPh3)2][BF4] (8).