- New ionic plastic crystals of NR4BEt3Me (R = Me and Et) and NRxR'4-xBEt3Me (R = Et, R' = Me and Pr, x = 13) in a new class of plastic crystals
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New ionic plastic crystals of NR4BEt3Me (R = Me and Et) and NRxR'4-xBEt3Me (R = Et, R' = Me and Pr, x = 13) were formed in a new region of plastic crystal. In this area, globular cations and anions are assembled by weak interactions. On the basis of our results of 1H and 13CNMR spectra and electrical conductivity measurements, we could conclude that isotropic reorientation and self-diffusion of globular cations and anions were detected in the crystal. X-ray diffraction (XRD) lines observed in RxR'4-xBEt3Me (R = Et, R' = Me, x = 04) revealed a CsCl-type cubic crystal structure. Additionally, DSC spectra revealed that this new class of plastic crystals displays low phase-transition temperatures in the plastic phase and have high melting points. The former tendency is frequently detected in molecular plastic crystals while the latter is often found in ionic plastic crystals.
- Hayasaki, Tomoyuki,Hirakawa, Satoru,Honda, Hisashi
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- Alkylation of ammonium salts catalyzed by imidazolium-based ionic liquid catalysts
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Quaternary ammonium salts were synthesized from ammonium salts and dialkyl carbonates over imidazolium ionic liquid catalysts. The reaction gave almost stoichiometric amounts of the quaternary ammonium salts for halides and nitrates. It was found that the electron-donating property of the alkyl moieties of ammonium cations, the electrophilic nature of the alkyl group of the carbonate, the acidity of the acid that the anion of the ammonium salt corresponds to, and the steric hindrance of the ammonium salts and the dialkyl carbonates are the key factors that influence the yields of quaternary ammonium salts. Strong electron-donating alkyl groups on the nitrogen atom of the ammonium salt, electron-withdrawing groups on the methylene carbon of dialkyl carbonate, and weaker steric hindrance of the starting ammonium salts and dialkyl carbonates favor the alkylation reaction of ammonium salts.
- Zheng, Zhuo Qun,Wang, Jie,Wu, Ting Hua,Zhou, Xiao Ping
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p. 1095 - 1101
(2008/03/27)
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- Novel one-pot synthesis of quaternary ammonium halides: New route to ionic liquids
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Treatment of an amide with an alkyl or substituted alkyl halide in the presence of a weak base in a one-pot reaction leads to crystalline quaternary ammonium halides with reasonable chemical yields; some of the compounds show low melting points and a liquid range of over 50-100°C before decomposition.
- Ropponen, Jarmo,Lahtinen, Manu,Busi, Sara,Nissinen, Maija,Kolehmainen, Erkki,Rissanen, Kari
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p. 1426 - 1430
(2007/10/03)
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- Wideline 185Re- and 187Re Solid-State NMR Spectroscopy of Metaperrhenates with Alkyl-Substituted Cations of Main Group V
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127I solid-state NMR spectra of metaperiodates with alkyl- or aryl-substituted cations of main group V yield second order quadrupole effects due to the distortion of the tetrahedra surrounding the iodine nuclei.In some cases the 127I quadrupole effects were found to become very small or even vanish.Thus the isomorphous metaperrhenates should also be accesible by 185Re, 187Re solid-state NMR.Owing to the very large quadrupole moments of the 185Re and 187Re isotopes, very small distortions or changes in dynamical effects can be detected in systems with such voluminous cations. The solid-state NMR spectra of (CH3)4AsReO4 yield the calculated 185Re, 187Re second order quadrupole effects.These result from two kinds of differently distorted ReO4- tetrahedra.X-ray investigations and calculations based on a point charge model for (CH3)4SbReO4 manifest the inaccessibility of quadrupole effects by wideline solid-sate NMR in a magnetic field of BO=4.698 Tesla.
- Burkert, Paul K.,Grommelt, Meinhard,Pietrass, Tanja,Lachmann, Joachim,Mueller, Gerhard
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p. 725 - 730
(2007/10/02)
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