- Synthesis of SCF3-Substituted Sulfonium Ylides from Sulfonium Salts or α-Bromoacetic Esters
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A metal-free direct trifluoromethylthiolation of sulfonium ylides with an electrophilic trifluoromethylthiolating reagent has been established, in which sulfonium salt or α-bromoacetic ester is employed as sulfonium ylide precursors. This trifluoromethylthiolation enables the straightforward construction of SCF3-substituted sulfonium ylides from a wide range of substrates, including ketones, esters, and even PEGylated substrates. Moreover, the application of this approach in large-scale preparation and the fluorescence and fluorine-19 magnetic resonance imaging capabilities of the product are also explored. (Figure presented.).
- Xiao, Yushan,Jia, Yimin,Huang, Jinfeng,Li, Xiangyu,Zhou, Zhiwen,Zhang, Jing,Jiang, Mou,Zhou, Xin,Jiang, Zhong-Xing,Yang, Zhigang
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supporting information
p. 738 - 743
(2022/01/11)
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- Low toxicity functionalised imidazolium salts for task specific ionic liquid electrolytes in dye-sensitised solar cells: A step towards less hazardous energy production
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Novel solvent free task specific ionic liquid (TSIL) electrolytes for dye sensitised solar cells (DSSC) were synthesised and tested. Of great concern is the replacement of low-moderate toxicity second generation ILs, with high toxicity third generation TSILs. As most 1-butyl-3-methylimidazolium (Bmim) and especially 1-ethyl-3-methylimidazolium (Emim) based ILs have low toxicity, the designing of replacement TSILs of comparable toxicity is a challenge. Structural features of TSIL investigated herein were incorporation of heteroatoms into the side chain of imidazolium cations (i.e. ether, ester and amide) and anion (bromide, iodide, and triflimide [NTf2]). Preliminary toxicity screening against 20 microorganisms (8 bacteria and 12 fungi) found that all ILs, imidazolium salts, N-butylbenzimidazole (NBB) and guanidinium thiocyanate (GNCS) do not exhibit high antimicrobial toxicity. However NBB and a pentyl ester substituted IL displayed moderate toxicity to several strains of bacteria and fungi. Further toxicity testing to establish IC50 values shows several novel TSIL compounds and imidazolium salts are in fact less toxic to microorganisms (e.g. bacteria) than commonly used 1-ethyl-3-methylimidazolium iodide (EmimI) and 1,3-dimethylimidazolium iodide (DmimI). We have demonstrated that the presence of ether and either ester or amide groups in the structure of the cation of the TSIL and imidazolium salts reduces antimicrobial toxicity, which is consistent with the lowering of the lipophilicity of ILs. Iodide and bromide analogues have lower toxicity than the NTf2 examples in this study. The DSSC performance using these "greener" ILs in place of the standard EmimI compare quite favourably. Two low antibacterial toxicity iodide examples exhibit photocurrents of 9.27 mA cm-2 and 8.85 mA cm -2, respectively, achieving promising efficiencies of 3.39% and 3.31%, respectively (EmimI = 4.94%). DSSC performance is further improved by 15% minimum to 66% maximum, depending on IL chosen, by the presence of small amounts of moisture and DSSCs employing a low antibacterial toxicity iodide TSIL or imidazolium salt can surpass the performance of dry EmimI. Of note the DSSC containing TSIL NTf2 examples, performed poorly compared to the halide analogues, with the outcome that the most toxic TSILs under investigation are also the least preferred based on performance. the Partner Organisations 2014.
- Ghavre, Mukund,Byrne, Owen,Altes, Lena,Surolia, Praveen K.,Spulak, Marcel,Quilty, Brid,Thampi, K. Ravindranathan,Gathergood, Nicholas
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supporting information
p. 2252 - 2265
(2014/04/17)
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- Biodegradable, non-bactericidal oxygen-functionalised imidazolium esters: A step towards 'greener' ionic liquids
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A series of imidazolium ionic liquids was prepared and screened against 7 bacterial strains. The incorporation of ether groups into the ester side-chain significantly reduced the toxicity compared with alkyl ester derivatives. Biodegradation data are also presented for 15 of the ionic liquids - including 6 examples which can be classed as readily biodegradable.
- Morrissey, Saibh,Pegot, Bruce,Coleman, Deborah,Garcia, M. Teresa,Ferguson, Damien,Quilty, Brid,Gathergood, Nicholas
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supporting information; experimental part
p. 475 - 483
(2010/04/22)
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- BIODEGRADABLE SOLVENTS FOR THE CHEMICAL INDUSTRY
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This invention relates to ionic liquid (ILs) solvents for chemical synthesis based on an alkyl - imidazolium cation core containing ionic liquids which have enhanced biodegradability and reduced toxicity relative to existing imidazolium bases ILs such as 1-butyl-3-methylimidazolium (bmmim) salts. Many of the described ILs produce a score of over 60% biodegradability over 28 days in a biodegradability test such as the Sturm Test, the Closed Bottle Test (OECD 301D) or the CO2 Headspace Test (ISO 14593). The ILs of the invention comprise an alkyl substituted imidazolium cationic core having a -C=OX- side chain in the 3-position of the imidazole ring, wherein X = O, NH, N or S and an associated counteranion characterized in that the -C=OX side chain comprises at least one ether linkage. The biodegradable and non-toxic IL may be used as green solvents for the chemical, pharmaceutical, biofuel and biomass industries. The ILs of the invention are particularly useful in hydrogenation, pericyclic and metathesis reactions.
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Page/Page column 17
(2009/04/25)
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