Synthesis and reactivity of water-soluble arene–ruthenium(II) complexes and dimerization of terminal alkynes in organic and aqueous media

• We reported new method for synthesis of water-soluble arene–ruthenium(II) complexes.
• Reaction of arene–ruthenium(II) complex with HCC(O)OR1 in R2OH was studied.
• Arene–ruthenium(II) complex catalyzes the dimerization of some terminal alkynes HCCR in organic and aqueous medium.
• Their structures are elucidated by IR, NMR and X-ray crystallography.

Treatment of the dimeric precursor [{RuCl(μ-Cl) (η6-C6H5OCH2CH2OH)}2] (1) with HNCPh2 in the presence of H2O afforded the arene–ruthenium(II) complex [(η6-C6H5OCH2CH2OH) (HN]CPh2)RuCl2] (2), as well as the aquo-species [(η6-C6H5OCH2CH2OH) (H2O)RuCl2] (3). The hydroxyethoxy substituent on the arene induces water-solubility of the resulting complexes. Reaction of 2 with HCC(O)OR1 in R2OH afforded the chelate vinyl ether complexes [Tp(PPh3)Ru–C(OR2)CHC(O)OR1] (4a, R1 = Me, R2 = Me; 4b, R1 = Et, R2 = Me; 4c, R1 = Et, R2 = Et; 4d, R1 = Me, R2 = Et), respectively. Preliminary results on the catalytic activity of 2 are also accessible. Intriguingly, complex 2 catalyzes the dimerization of some terminal alkynes HCCR in organic and aqueous medium. Whereas with R = COOMe, E-selective head-to-head dimerization takes place exclusively, in the case of R = SiMe3, t-Bu isomeric mixtures of head-to-head and head-to-tail coupling products are obtained. The structure of 3 has been determined by X-ray diffraction analysis.

Treatment of the dimeric precursor 1 with HNCPh2 in the presence of H2O afforded 2, as well as the aquo-species 3. Reaction of 2 with HCC(O)OR1 in R2OH afforded the chelate vinyl ether complexes. Preliminary results on the catalytic activity of 2 are also accessible.Figure optionsDownload as PowerPoint slide