26127-08-2Relevant articles and documents
Biochemical Responses of Wheat Seedlings on the Introduction of Selected Chiral Ionic Liquids to the Soils
Pawlowska, Barbara,Feder-Kubis, Joanna,Telesiński, Arkadiusz,Biczak, Robert
, p. 3086 - 3095 (2019/03/19)
In this study, new chiral ionic liquids (CILs) were obtained from the natural-origin material (1R,2S,5R)-(-)-menthol. The physicochemical characteristics of the studied imidazolium salts were investigated. The obtained 3-ethyl-1-[(1R,2S,5R)-(-)-menthoxy-m
Synthesis and spectroscopic properties of symmetrical ionic liquids based on (?)-menthol
Feder-Kubis, Joanna
, p. 63 - 70 (2017/01/14)
Several symmetrical imidazolium salts were obtained from the natural chiral pool of (1R,2S,5R)-(?)-menthol. First 1,3-bis[(1R,2S,5R)-(?)-menthoxymethyl]imidazolium chloride, which is a prototype for ionic liquids, was prepared with the use of two different methods. Furthermore, metathesis of this symmetrical imidazolium chloride with various salts was carried out. The ion exchange reaction goes smoothly, with the satisfactory yield of 97.5 to 99.5%. Obtained 1,3-bis[(1R,2S,5R)-(?)-menthoxymethyl]imidazolium salts are stable in the air, in contact with water and in commonly used organic solvents. Moreover they are non-volatile and non-flammable. Discussed symmetrical salts belong to chiral ionic liquids (CILs) where the chirality resided in the cation and is associated with the presence of optically active (1R,2S,5R)-(?)-menthol. The diastereotopic protons in the 1H NMR were thoroughly described. Moreover, the 1H NMR and 13C NMR spectra indicated notable differences in the chemical shifts depending on the anion used. Comparing the differences between values of the chemical shifts, the anions were ordered according to their increasing shielding capacities. The changing of the electron density surrounding the imidazolium ring was discussed.
Synthesis of inexpensive chiral half-sandwich nickel N-heterocyclic carbene complexes: X-ray diffraction study of the D-menthyl-functionalized complex [Ni(iPr2Ph-NHC-CH2OMent)ClCp]
Rocquin, Mansuy,Ritleng, Vincent,Barroso, Sónia,Martins, Ana M.,Chetcuti, Michael J.
, p. 57 - 62 (2018/03/27)
The imidazolium salts, 1-(2,4,6-trimethylphenyl)-3-[(1R,2S,5R)-(?)-menthoxymethyl]imidazolium chloride (Mes-NHC-CH2OMent·HCl) (1a) and 1-(2,6-diisopropylphenyl)-3-[(1R,2S,5R)-(?)-menthoxymethyl]imidazolium chloride (iPr2Ph-NHC-CH2OMent·HCl) (1b), are readily accessible from inexpensive (1R,2S,5R)-(?)-menthol. They react with nickelocene to give two new chiral nickel-N-heterocyclic carbene (NHC) complexes, [Ni(Mes-NHC-CH2OMent)ClCp] (2a) and [Ni(iPr2Ph-NHC-CH2OMent)ClCp] (2b), in good yields. The new complexes were fully characterized by standard spectroscopic techniques and by a single crystal X-ray diffraction study on complex 2b. Complex 2b crystallizes in the chiral spacegroup P1, with two independent molecules in the unit cell, which are slightly different from each other. Preliminary studies show that these complexes are effective catalysts for the hydrosilylation of ketones. However no chiral induction was observed.