- Phosphonium-phosphates/thiophosphates: Ionic liquids or liquid ion pairs? NMR spectroscopic classification
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Structurally unique ionic liquids phosphonium-phosphate and phosphonium-thiophosphate, having both phosphorus based counter ions, in which the anionic part is represented by di-aryl phosphate or di-aryl thiophosphate and cations been tetraalkylphosphonium groups, behave differently in terms of their NMR behaviour. While phosphonium-phosphates show significant changes in its 1H, 13C and 31P NMR chemical shifts vis. á vis. corresponding chemical shifts for a physical mixture of tetraalkylphosphonium bromide and di-aryl phosphate, phosphonium-thiophosphates behave almost similarly in terms of NMR with their synthetic precursors, hence indicating phosphate-phosphonium interaction has a significant covalent component resembling more to a liquid ion pair while thiophosphate-phosphonium interaction is principally ionic in nature. Translational diffusion behavior studied by PFGSE-NMR experiments and ionic conductivities of these ionic liquids in chloroform solution corroborated the hypothesis. The effect of variable alkyl chain length in phosphonium cation is effectively observed in the extent of ion association. Results of this study may provide insight into the solution state behavior of these ionic liquids, would help to classify those in terms of their strength of ion association and thus potential application thereof.
- Mondal, Sujit,Mandal, Tanmay,Sharma, Meeta,Kumar, Ravindra,Arora, Ajay K.,Bansal, Veena,Christopher,Kapur
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p. 2460 - 2464
(2017/06/01)
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- Lamellar structures in fluorinated phosphonium ionic liquids: The roles of fluorination and chain length
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Ionic liquids (ILs) exhibit tunable behaviour and properties that are due to their supramolecular structure. We synthesized a series of alkylated and fluorinated phosphonium dicyanamide ILs to study the relation between molecular structure and assembly with a focus on the roles of cation chain length and fluorination. Small angle X-ray scattering indicated a lamellar structure with long-range order for all fluorinated ILs, while alkylated ILs showed only the general structures of ILs, i.e., alternating a polar ionic-zone and a nonpolar alkyl-zone. "Fluorophobic" interactions caused microphase segregation between perfluorinated and other molecular segments, "fluorophilic" interactions among the perfluorinated segments stabilized the microphase structure, and the coupling of "fluorophobic" and "fluorophilic" interactions resulted in a stable mesophase structure. The perfluorinated segments packed more densely than the alkylated analogues; the fluorinated versions (except for F2) liquefied at temperatures considerably above that of alkylated ILs. The lamellar structures strongly affected the rheology of the ILs. Fluorinated ILs had higher viscosities and exhibited non-Newtonian shear thinning; the alkylated ILs of the same length had an order of magnitude lower viscosities and were purely Newtonian. We propose that the disruption of lamellar structure in the shear flow causes the non-Newtonian flow behaviour.
- Rauber, Daniel,Zhang, Peng,Huch, Volker,Kraus, Tobias,Hempelmann, Rolf
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p. 27251 - 27258
(2017/10/27)
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- Coordination Catalysis in Organic Electrosynthesis. Electrochemical Phosphorylation of Organic Halides in the Presence of Samarium Dichloride
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The feasibility was demonstrated for arylation (or alkylation) of white phosphorus under the action of electrochemically generated Sm(II).
- Budnikova,Yakhvarov,Kargin
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p. 566 - 569
(2007/10/03)
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- Process for the preparation of substantially fluorinated alkyl bromides
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According to the process according to the invention, substantially fluorinated alkyl bromides, preferably perfluoroalkyl bromides, are prepared by reaction of substantially fluorinated alkyl iodides, with phase transfer catalysts in the bromide form.
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- Process for the preparation of substantially fluorinated alkyl bromides
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According to the process according to the invention, substantially fluorinated alkyl bromides, preferably perfluoroalkyl bromides, are prepared by reaction of substantially fluorinated alkyl iodides with organic bromine compounds in which the bromine atom is bound covalently to a carbon atom or a nitrogen atom.
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- Alcohols and aldehydes prepared from olefins and synthesis gas
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This invention concerns a process of preparing alcohols and aldehydes which comprises the steps of contacting a mixture of terminal and/or internal olefins and synthesis gas with a catalyst system comprising a ruthenium-containing compound dispersed in a low melting quaternary phosphonium or ammonium base or salt and heating said resultant reaction mixture under a pressure of 100 psi or greater at a temperature of at least 50° C. for a sufficient time to produce said alcohols and aldehydes.
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- 1H-NMR- AND MOESSBAUER INVESTIGATIONS ON THE ION PAIRS OF TETRACHLOROFERRATE(III) ANION WITH QUATERNARY PHOSPHONIUM CATIONS
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Paramagnetic ion pairs were investigated by 1H-NMR and Moessbauer spectroscopy in chloroform and dimethyl sulphoxide.It has been shown that the chemical shifts of 1H-NMR peaks arise from a combination of contact and pseudocontact interactions of opposite sign, and the ratio of interactions was definitely influenced by the extent of solvation.On the basis of Moessbauer measurements it was shown that the change of the cation size had an effect on the electron delocalization and symmetry conditions of iron(III) in solid samples, too.In concentrated frozen solutions of ion pairs, different interactions were indicated by Moessbauer spectros copy in chloroform and dimethyl sulphoxide, in accordance with 1H-NMR results.However, in dilute solution such an anion-solvent interaction was observed directly, which could be shown by the NMR method only indirectly.
- Vincze, L.,Papp, S.
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p. 153 - 162
(2007/10/02)
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