N,O-bis（trimethylsily）trifluoroacetamide （BSTFA） and N-methyl-N（trimethylsily） trifluoroacetamide （MSTFA） are common derivatization reagents used in the GC-MS analysis of estrogen steroids such as estrone （El...N,O-bis（trimethylsily）trifluoroacetamide （BSTFA） and N-methyl-N（trimethylsily） trifluoroacetamide （MSTFA） are common derivatization reagents used in the GC-MS analysis of estrogen steroids such as estrone （El） and 17α-ethinylestradiol （EE2）. In this study, three trimethylsilyl （TMS） steroid derivatives, mono- and di-trimethylsilyl EE2 and mono-trimethylsilyl El, were observed during the derivatization of EE2 with BSTFA or MSTFA and/or GC separation. Factors influencing the production of multiple TMS derivatives and their relative abundance were examined. It was found that both methanol and bisphenol A competed with estrogenic esteroids when reacting with silylation reagents, and thus affected the formation of TMS derivatives and their relative abundance in the derivatization products. Methanol was found to be more reactive than bisphenol A with the BSTFA reagent. None of the three solvents tested in this study could prevent the generation of multiple TMS derivatives during the derivatization of EE2 with BSTFA, followed by GC analysis. A similar result was observed using MSTFA as the derivative reagent followed by GC analysis. Thus, the suitability of BSTFA or MSTFA as the derivatization reagent for the determination of E1 and EE2 by GC-MS, under the conditions reported here, is questionable. This problem can be solved by adding trimethylsilylimidaz （TMSI） in the BSTFA reagent as recommended, and the performance of the method has been proved in this study.展开更多
Tris(trimethylsilyl)borate(TMSB) has been intensively studied to improve the performances of lithiumion batteries. However, it is still an interesting issue needed to be resolved for the research on the Li^(+) solvati...Tris(trimethylsilyl)borate(TMSB) has been intensively studied to improve the performances of lithiumion batteries. However, it is still an interesting issue needed to be resolved for the research on the Li^(+) solvation structure affected by TMSB additive. Herein, the electrochemical tests, quantum chemistry calculations, potential-resolved in-situ electrochemical impedance spectroscopy measurements and surface analyses were used to explore the effects of Li^(+) solvation structure with TMSB additive on the formation of the cathode electrolyte interface(CEI) film in LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/Li half cells. The results reveal that the TMSB additive is easy to complex with Li^(+) ion, thus weaken the intermolecular force between Li^(+) ions and ethylene carbonate solvent, which is benefit for the cycle performance. Besides, the changed Li^(+) solvation structure results in a thin and dense CEI film containing compounds with Si–O and B–O bonds which is favorable to the transfer of Li^(+) ions. As a result, the performances of the LNCM811/Li half cells are effectively improved. This research provides a new idea to construct a high-performance CEI film by adjusting the Li^(+) solvation structures.展开更多
N-Boc-2, 5-bis(trimethylsilyl)pyrrolidine 4 was synthesized from the reaction of N-Boc-pyrrolidine 1 with trimethylsilyl chloride (TMSCl) at optional temperature in one-pot in good yield.
Trimethylsilylated silica was synthesized. through hydrolytic condensation of tetraethoxysilane followed by trimethylsilylation. Rheological properties of the silicone resin with trimethylsilylated silica as modifier ...Trimethylsilylated silica was synthesized. through hydrolytic condensation of tetraethoxysilane followed by trimethylsilylation. Rheological properties of the silicone resin with trimethylsilylated silica as modifier were studied. It turned out that the particle size of silica was important to the rheological behavior of the modified resin. Trimethylsilylated silica of medium particle size shows the strongest tendency of forming physical network in the resin.展开更多
A mild, efficient and fast method for direct oxidation of trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds using trinitratocerium（Ⅳ） bromate （TNCB） supported on...A mild, efficient and fast method for direct oxidation of trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds using trinitratocerium（Ⅳ） bromate （TNCB） supported on NaHSO4.H2O under solvent-free conditions is reported.展开更多
Surface modification of poly [1-(trimethylsilyl)-1-propyne] (PTMSP) membranes bybromine vapor has been studied. It is shown that Br/C atomic ratio at the surfaces increased withthe time of bromination until about 60 m...Surface modification of poly [1-(trimethylsilyl)-1-propyne] (PTMSP) membranes bybromine vapor has been studied. It is shown that Br/C atomic ratio at the surfaces increased withthe time of bromination until about 60 min, then it reached a plateau. The results of XPS and IRstudies indicated that the addition of bromine to double bonds and the replacement of H on CH_3 bybromine had taken place so that a new peak at 286.0 eV (C--Br)in C_(1s) spectra and some newbands, e. g. at 1220 and 580cm^(-1) in IR spectra were formed. The fact,t Po_2, permeability ofoxygen, decreased and α_(O_2/N_2), separation factor of oxygen relative to nitrogen, increased withbromination time, shows that surface modification of PTMSP by bromine may be an efficient approach to prepare PTMSP membranes used for practical gas separations.展开更多
The influence of tris(trimethylsilyl) borate (TMSB) as an electrolyte additive on lithium ion cells have been studied using Li/LiCo1/3Ni1/3Mn1/3O2 cells at a higher voltage, 4.7 V versus Li/Li+. 1 wt% TMSB can dramati...The influence of tris(trimethylsilyl) borate (TMSB) as an electrolyte additive on lithium ion cells have been studied using Li/LiCo1/3Ni1/3Mn1/3O2 cells at a higher voltage, 4.7 V versus Li/Li+. 1 wt% TMSB can dramatically reduce the capacity fading that occurs during cycling at room temperature (RT) and elevated temperature (60 degrees C). After 150 cycles at 1 C rate (1 C= 278 mAh/g), the capacity retention of Li/LiCo1/3Ni1/3Mn1/3O2 is up to near 72% in the electrolyte with TMSB added, while it is only about 35% in the baseline electrolyte. The electrochemical behaviors, the surface chemistry and structure of Li/LiCo1/3Ni1/3Mn1/3O2 cathode are characterized with charge/discharge test, linear sweep voltammetry (LSV), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), thermal gravimetric analyses (TGA), scanning electron microscope (SEM) and transmission electron microscopy (TEM). These analysis results reveal that the addition of TMSB is able to protectively modify the electrode CEI film in a manner that suppresses electrolyte decomposition and degradation of electrode surface structure, even though at both a higher voltage of 4.7 V and an elevated temperature of 60 degrees C. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.展开更多
Lead free tin perovskite solar cells(PKSCs)are the most suitable alternative candidate for conventional lead perovskite solar cells.However,the efficiency and the stability are insufficient,mainly because of the poor ...Lead free tin perovskite solar cells(PKSCs)are the most suitable alternative candidate for conventional lead perovskite solar cells.However,the efficiency and the stability are insufficient,mainly because of the poor film quality and numerous defects.Here we introduce an efficient strategy based on a simple trimethylsilyl halide surface passivation to increase the film quality and reduce the defect density.At the same time,a hydrophobic protective layer on the perovskite surface is formed,which enhanced the PKSCs’stability.The efficiency of the solar cell after the passivation was enhanced from 10.05%to 12.22%with the improved open-circuit voltage from 0.57 V to 0.70 V.In addition,after 92 days of storage in N_(2) filled glovebox,the modified T-PKSCs demonstrated high stability maintaining 80%of its initial efficiency.This work provides a simple and widely used strategy to optimize the surface/interface optoelectronic properties of perovskites for giving more efficient and stable solar cells and other optoelectronic devices.展开更多
A reliable method is described for the detection of amitoride,triamterene. canrenone and spironolactone in human urine using GC-MS analysis after trimethytsitytation.The mass spectrometric and metabotic features of th...A reliable method is described for the detection of amitoride,triamterene. canrenone and spironolactone in human urine using GC-MS analysis after trimethytsitytation.The mass spectrometric and metabotic features of the compounds are discussed展开更多
基金Project supported by the National Basic Research Program (973) of China(No. 2007CB407301)Beijing Municipal Natural Science Foundation(No. 8061004).
文摘N,O-bis（trimethylsily）trifluoroacetamide （BSTFA） and N-methyl-N（trimethylsily） trifluoroacetamide （MSTFA） are common derivatization reagents used in the GC-MS analysis of estrogen steroids such as estrone （El） and 17α-ethinylestradiol （EE2）. In this study, three trimethylsilyl （TMS） steroid derivatives, mono- and di-trimethylsilyl EE2 and mono-trimethylsilyl El, were observed during the derivatization of EE2 with BSTFA or MSTFA and/or GC separation. Factors influencing the production of multiple TMS derivatives and their relative abundance were examined. It was found that both methanol and bisphenol A competed with estrogenic esteroids when reacting with silylation reagents, and thus affected the formation of TMS derivatives and their relative abundance in the derivatization products. Methanol was found to be more reactive than bisphenol A with the BSTFA reagent. None of the three solvents tested in this study could prevent the generation of multiple TMS derivatives during the derivatization of EE2 with BSTFA, followed by GC analysis. A similar result was observed using MSTFA as the derivative reagent followed by GC analysis. Thus, the suitability of BSTFA or MSTFA as the derivatization reagent for the determination of E1 and EE2 by GC-MS, under the conditions reported here, is questionable. This problem can be solved by adding trimethylsilylimidaz （TMSI） in the BSTFA reagent as recommended, and the performance of the method has been proved in this study.
基金supported by the National Natural Science Foundation of China(51962019)the Natural Science Foundation of Gansu Province(20JR5RA469)+1 种基金the Education Department of Gansu Province:"Star of Innovation"Project for Outstanding Graduate Students(2021CXZX-455)the Lanzhou University of Technology Hongliu First-class Discipline Construction Program。
文摘Tris(trimethylsilyl)borate(TMSB) has been intensively studied to improve the performances of lithiumion batteries. However, it is still an interesting issue needed to be resolved for the research on the Li^(+) solvation structure affected by TMSB additive. Herein, the electrochemical tests, quantum chemistry calculations, potential-resolved in-situ electrochemical impedance spectroscopy measurements and surface analyses were used to explore the effects of Li^(+) solvation structure with TMSB additive on the formation of the cathode electrolyte interface(CEI) film in LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/Li half cells. The results reveal that the TMSB additive is easy to complex with Li^(+) ion, thus weaken the intermolecular force between Li^(+) ions and ethylene carbonate solvent, which is benefit for the cycle performance. Besides, the changed Li^(+) solvation structure results in a thin and dense CEI film containing compounds with Si–O and B–O bonds which is favorable to the transfer of Li^(+) ions. As a result, the performances of the LNCM811/Li half cells are effectively improved. This research provides a new idea to construct a high-performance CEI film by adjusting the Li^(+) solvation structures.
基金the National Natural Science Foundation of China (No 29772004).
文摘N-Boc-2, 5-bis(trimethylsilyl)pyrrolidine 4 was synthesized from the reaction of N-Boc-pyrrolidine 1 with trimethylsilyl chloride (TMSCl) at optional temperature in one-pot in good yield.
文摘Trimethylsilylated silica was synthesized. through hydrolytic condensation of tetraethoxysilane followed by trimethylsilylation. Rheological properties of the silicone resin with trimethylsilylated silica as modifier were studied. It turned out that the particle size of silica was important to the rheological behavior of the modified resin. Trimethylsilylated silica of medium particle size shows the strongest tendency of forming physical network in the resin.
文摘A mild, efficient and fast method for direct oxidation of trimethylsilyl, tetrahydropyranyl and methoxymethyl ethers to their corresponding carbonyl compounds using trinitratocerium（Ⅳ） bromate （TNCB） supported on NaHSO4.H2O under solvent-free conditions is reported.
基金The project is supported by the National Natural Science Foundation of China
文摘Surface modification of poly [1-(trimethylsilyl)-1-propyne] (PTMSP) membranes bybromine vapor has been studied. It is shown that Br/C atomic ratio at the surfaces increased withthe time of bromination until about 60 min, then it reached a plateau. The results of XPS and IRstudies indicated that the addition of bromine to double bonds and the replacement of H on CH_3 bybromine had taken place so that a new peak at 286.0 eV (C--Br)in C_(1s) spectra and some newbands, e. g. at 1220 and 580cm^(-1) in IR spectra were formed. The fact,t Po_2, permeability ofoxygen, decreased and α_(O_2/N_2), separation factor of oxygen relative to nitrogen, increased withbromination time, shows that surface modification of PTMSP by bromine may be an efficient approach to prepare PTMSP membranes used for practical gas separations.
文摘The influence of tris(trimethylsilyl) borate (TMSB) as an electrolyte additive on lithium ion cells have been studied using Li/LiCo1/3Ni1/3Mn1/3O2 cells at a higher voltage, 4.7 V versus Li/Li+. 1 wt% TMSB can dramatically reduce the capacity fading that occurs during cycling at room temperature (RT) and elevated temperature (60 degrees C). After 150 cycles at 1 C rate (1 C= 278 mAh/g), the capacity retention of Li/LiCo1/3Ni1/3Mn1/3O2 is up to near 72% in the electrolyte with TMSB added, while it is only about 35% in the baseline electrolyte. The electrochemical behaviors, the surface chemistry and structure of Li/LiCo1/3Ni1/3Mn1/3O2 cathode are characterized with charge/discharge test, linear sweep voltammetry (LSV), X-ray photoelectron spectroscopy (XPS), electrochemical impedance spectroscopy (EIS), thermal gravimetric analyses (TGA), scanning electron microscope (SEM) and transmission electron microscopy (TEM). These analysis results reveal that the addition of TMSB is able to protectively modify the electrode CEI film in a manner that suppresses electrolyte decomposition and degradation of electrode surface structure, even though at both a higher voltage of 4.7 V and an elevated temperature of 60 degrees C. (C) 2016 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.
文摘Lead free tin perovskite solar cells(PKSCs)are the most suitable alternative candidate for conventional lead perovskite solar cells.However,the efficiency and the stability are insufficient,mainly because of the poor film quality and numerous defects.Here we introduce an efficient strategy based on a simple trimethylsilyl halide surface passivation to increase the film quality and reduce the defect density.At the same time,a hydrophobic protective layer on the perovskite surface is formed,which enhanced the PKSCs’stability.The efficiency of the solar cell after the passivation was enhanced from 10.05%to 12.22%with the improved open-circuit voltage from 0.57 V to 0.70 V.In addition,after 92 days of storage in N_(2) filled glovebox,the modified T-PKSCs demonstrated high stability maintaining 80%of its initial efficiency.This work provides a simple and widely used strategy to optimize the surface/interface optoelectronic properties of perovskites for giving more efficient and stable solar cells and other optoelectronic devices.
文摘A reliable method is described for the detection of amitoride,triamterene. canrenone and spironolactone in human urine using GC-MS analysis after trimethytsitytation.The mass spectrometric and metabotic features of the compounds are discussed
