Traditionally,Hofmeister effect was understood on the basis of hydration abilities of ions.Recent studies found short-range structuring effects of ions on water which shifted the attention from ion-water interaction t...Traditionally,Hofmeister effect was understood on the basis of hydration abilities of ions.Recent studies found short-range structuring effects of ions on water which shifted the attention from ion-water interaction to ion-protein interaction.In this study,ATR-FTIR spectroscopy at different RH is used to study the effect of a representative Kosmotrope(MgSO4),Chaotrope(NH4NO3)and neutral(KCl)salt on glycine.The salting out,salting in and neutral effects of salts on glycine are found aligned with Hofmeister effect.Interestingly,direct interaction of kosmotrope anion(SO2-4)with the glycine is observed experimentally which validates the recent idea of ion-protein interaction.Further detailed studies will be needed for deeper insight.展开更多
Molecular interactions of a representative pyrrolidinium-based ionic liquid 1-butyl-l-methyl-pyrrolidinium bis（triflorosulfonyl）- imide （[BMPyrr][TFSI]） with dimethyl sulfoxide （DMSO） and acetonitrile （AN） hav...Molecular interactions of a representative pyrrolidinium-based ionic liquid 1-butyl-l-methyl-pyrrolidinium bis（triflorosulfonyl）- imide （[BMPyrr][TFSI]） with dimethyl sulfoxide （DMSO） and acetonitrile （AN） have been analyzed in this work. Attenuated total reflection Fourier transform infrared spectroscopy （ATR-FTIR） and density functional theory （DFT） calculations are used in the investigation, while excess infrared spectra and two-dimensional correlation spectroscopy are used to explore the data in detail. It has been found that the molecular solvents can interact with TFSI- （mainly with S=O and weakly with S-N-S group）. AN interacts feebly with BMPyrr＋ as compared with the strong interaction of DMSO. The strength of the interactions depends on the electron donating ability of the solvent. Upon mixing, hydrogen bonds regarding C-Hs in cation and S-N-S in anion are weakened, while that regarding S=O in anion is strengthened. Among the C-Hs which are connected directly with the N of the cation, Cl-H is the main interaction site for both DMSO and AN. This means that Cl-H is the most acidic hydrogen in pyrrolidinium cation.展开更多
基金National Natural Science Foundation of China(91544223,41875144)
文摘Traditionally,Hofmeister effect was understood on the basis of hydration abilities of ions.Recent studies found short-range structuring effects of ions on water which shifted the attention from ion-water interaction to ion-protein interaction.In this study,ATR-FTIR spectroscopy at different RH is used to study the effect of a representative Kosmotrope(MgSO4),Chaotrope(NH4NO3)and neutral(KCl)salt on glycine.The salting out,salting in and neutral effects of salts on glycine are found aligned with Hofmeister effect.Interestingly,direct interaction of kosmotrope anion(SO2-4)with the glycine is observed experimentally which validates the recent idea of ion-protein interaction.Further detailed studies will be needed for deeper insight.
基金supported by the National Natural Science Foundation of China (21133009, 21473099)
文摘Molecular interactions of a representative pyrrolidinium-based ionic liquid 1-butyl-l-methyl-pyrrolidinium bis（triflorosulfonyl）- imide （[BMPyrr][TFSI]） with dimethyl sulfoxide （DMSO） and acetonitrile （AN） have been analyzed in this work. Attenuated total reflection Fourier transform infrared spectroscopy （ATR-FTIR） and density functional theory （DFT） calculations are used in the investigation, while excess infrared spectra and two-dimensional correlation spectroscopy are used to explore the data in detail. It has been found that the molecular solvents can interact with TFSI- （mainly with S=O and weakly with S-N-S group）. AN interacts feebly with BMPyrr＋ as compared with the strong interaction of DMSO. The strength of the interactions depends on the electron donating ability of the solvent. Upon mixing, hydrogen bonds regarding C-Hs in cation and S-N-S in anion are weakened, while that regarding S=O in anion is strengthened. Among the C-Hs which are connected directly with the N of the cation, Cl-H is the main interaction site for both DMSO and AN. This means that Cl-H is the most acidic hydrogen in pyrrolidinium cation.
