1407833-79-7Relevant academic research and scientific papers
Ruthenium(II) Arene complexes with asymmetrical guanidinate ligands: Synthesis, characterization, and application in the base-free catalytic isomerization of allylic alcohols
Garcia-Alvarez, Rocio,Suarez, Francisco J.,Diez, Josefina,Crochet, Pascale,Cadierno, Victorio,Antinolo, Antonio,Fernandez-Galan, Rafael,Carrillo-Hermosilla, Fernando
, p. 8301 - 8311 (2012)
The ruthenium(II) arene dimer [{RuCl(μ-Cl)(η6-p-cymene)} 2] readily reacted with 4 equiv of guanidines (iPrHN) 2C=NR (R = iPr (1a), 4-C6H4 tBu (1b), 4-C6H4Br (1c), 2,4,6-C 6H2Me3 (1d), 2,6-C6H 3iPr2 (1e)) in toluene at room temperature to generate the mononuclear complexes [RuCl{κ2N,N'-C(NR)(N iPr)NHiPr}(η6-p-cymene)] (2a-e) and the easily separable guanidinium chloride salts [(iPrHN) 2C(NHR)][Cl] (3a-e). Compounds 2a-e and 3a-e were fully characterized by elemental analysis and IR and NMR spectroscopy. The structures of [RuCl{κ2N,N'-C(NiPr)2NH iPr}(η6-p-cymene)] (2a) and [RuCl{κ 2N,N'-C(N-4-C6H4tBu)(N iPr)NHiPr}(η6-p-cymene)] (2b) were also determined by X-ray diffraction analysis. Regardless of the steric requirements of the aromatic substituents, a nonsymmetric coordination of the guanidinate anions in 2b-e was observed, in complete accord with theoretical calculations (DFT) on the corresponding [RuCl{κ2N,N'-C(NR)(N iPr)-NHiPr}(η6-p-cymene)] and [RuCl{κ2N,N'-C(NiPr)2NHR} (η6-p-cymene)] models. Remarkably, complexes 2a-e were active catalysts for the redox isomerization of allylic alcohols in the absence of base, which represents the first catalytic application known for ruthenium guanidinate species.
