165463-49-0

Upstream product

• 673-32-5 1-Phenylprop-1-yne 

Downstream Products

• 175607-29-1 ReBr(C₅H₅)(C₆H₅CCCH₃)(P(C₆H₅)3)⁽¹⁺⁾*PF₆^(1-) = [ReBr(C₅H₅)(C₆H₅CCCH₃)(P(C₆H₅)3)]PF₆ 
• 199395-08-9 Re(C₅H₅)(C(C₆H₅)C(CH₃)CHCHC₆H₄P(C₆H₅)2)⁽¹⁺⁾*BF₄^(1-) = [Re(C₅H₅)(C(C₆H₅)C(CH₃)CHCHC₆H₄P(C₆H₅)2)]BF₄ 

Relevant academic research and scientific papers

Synthesis and reactivity of η2(4e)-alkyne and η2(3e)-vinyl complexes of rhenium

Reaction of cis-/trans-[ReBr2(CO)2(η-C5H5)] with PhC2Ph and MeC2Ph in refluxing toluene afforded good yields of the n2(4e)-donor alkyne complexes [ReBr2(η2-PhC2Ph)(η-C5H 5)] 1 and [ReBr2(η2-MeC2Ph)(η-C5H 5)] 2, respectively. Treatment of 1 and 2 with either AgBF4 or TlPF6 in the presence of PPh3, PMePh2 or P(OMe)3 (L) gave monocations [ReBr{η2(4e)-alkyne}L(η-C5H5)] +, whereas a similar reaction with 2 equivalents of AgBF4 and 1 equivalent of Ph2PCH2CH2PPh2 (dppe) afforded dications [Re(η2-PhC2Ph)(dppe)(η-C5H 5)][BF4]2 and [Re(η2-MeC2Ph)(dppe)(η-C5H 5)][BF4]2. The structural identity of [ReBr(η2-PhC2Ph)(PMePh2)(η-C 5H5)][PF6] was confirmed by single-crystal X-ray crystallography. The alkyne C-C vector lies parallel to the Re-Br bond and the alkyne C-C bond length [C(1)-C(2) 1.26(4) A] is relatively short. Treatment of [ReBr(η2-PhC2Ph)(PPh3)(η-C 5H5)][BF4] and [ReBr(η2-PhC2Ph)(PMePh2)-(η-C 5H5)][PF6] with K[BHBus3] in dichloromethane at -78°C led to neutral η2(3e)-vinyl complexes [Re{=C(Ph)CHPh}Br(PPh3)(η-C5H5)] and [Re{=C(Ph)CHPh}Br(PMePh2)(η-C5H5)]. The crystal structure of the latter showed that the C-C vector of the vinyl moiety lies almost parallel to the Re-Br bond. The stereochemistry of these reactions is discussed in the light of extended-Hueckel molecular orbital calculations. Reaction (-78°C) of [Re(η2-PhC2Ph)(dppe)(η-C5H 5)][BF4]2 with 1 equivalent of K[BHBus3] in tetrahydrofuran afforded the X-ray crystallographically identified monocationic η2(3e)-vinyl complex [Re{=C(Ph)CHPh}(dppe)(η-C5H5)][BF4], which reacted at room temperature with a further equivalent of K[BHBus3] to give the cis-stilbene-substituted complex [Re(η2-Z-PhCH=CHPh)(dppe)(η-C5H5)]. The crystal structure of the latter showed that the alkene phenyl substituents are orientated towards the cyclopentadienyl ring. In contrast, a similar reaction between K[BHBus3] and [Re(η2-MeC2Ph)(dppe)(η-C5H 5)][BF4]2 gave initially the η2(3e)-vinyl complex [Re{=C(Me)CHPh}(dppe)(η-C5H5)][BF4]; a further equivalent of K[BHBus3] led to deprotonation and formation of the η2-allene complex [Re{η2-CH(Ph)=C=CH2}(dppe)-(η-C5H 5)], in which the substituted allenic bond is co-ordinated to the rhenium. The dinuclear complex [Re2Br2(PPh3)2(μ-O)(η-C 5H5)2][BF4]2 was also prepared and shown crystallographically to possess a single rhenium-rhenium bond [2.731(5) A].

Formation of cisoid-η4(5e)-Butadienylrhenium Complexes by Coupling of Alkene and Alkyne Ligands

The reaction of the η2(4e)-bonded alkyne complexes 2-RC2Ph)(η-C5H5)> (R = Me or Ph) with o-diphenylphosphinostyrene and 2 equiv.AgBF4 in THF surprisingly affords HBF4, AgBr and excellent yields of the cationic η4(5e)-butadienyl complexes 3-(η-C5H5)>; the methyl-substituted system being structurally characterised by a single-crystal X-ray diffraction study.