Two novel heteroatom-bridged his (benzo-12-crown-4 ether)s, i.e. his [2-nitro-4,5 (1,4,7,10-tetraoxadecamethylene) disulfide 1 and diselenide 2, have been synthesized. X ray crystallographic structure was obtained for...Two novel heteroatom-bridged his (benzo-12-crown-4 ether)s, i.e. his [2-nitro-4,5 (1,4,7,10-tetraoxadecamethylene) disulfide 1 and diselenide 2, have been synthesized. X ray crystallographic structure was obtained for 1. Ion selective electrodes (ISE) for Ag+, containing 1 and 2 in PVC membrane as neutral carriers, were prepared, and their selectivity coefficients for Ag^+ (K_(Ag.M)^(pot)) were determined against other heavy metal ions, alkali and alkaline-earth metal ions. and ammonium ion. These ISEs showed excellent Ag^+ selectivities, log K_(Ag.M)^(pot) ≤ -3.8, against most of the interfering canons examined, except for Hg^+.展开更多
A new chiral multidenate ligand (S, S)-1,7-bis(4-benzyloxazolin-2-yl-methyl)-1, 7-diaza- 12-crown-4 1 has been synthesized and used as ligand in the copper catalyzed asymmetric cyclopropanation of 1, 1-diphenylethylene.
A once overlooked source of electrolyte degradation incurred by dissolved manganese(Ⅱ)species in lithium-ion batteries has been identified recently.In order to deactivate the catalytic activity of such manganese(II)i...A once overlooked source of electrolyte degradation incurred by dissolved manganese(Ⅱ)species in lithium-ion batteries has been identified recently.In order to deactivate the catalytic activity of such manganese(II)ion,1-aza-12-crown-4-ether(A12C4)with cavity size well matched manganese(Ⅱ)ion is used in this work as electrolyte additive.Theoretical and experimental results show that stable complex forms between A12C4 and manganese(II)ions in the electrolyte,which does not affect the solvation of Li ions.The strong binding effect of A12C4 additive reduces the charge density of manganese(II)ion and inhibits its destruction of the PF_(6)^(-)structure in the electrolyte,leading to greatly improved thermal stability of manganese(II)ions-containing electrolyte.In addition to bulk electrolyte,A12C4 additive also shows capability in preventing Mn^(2+) from degrading SEI on graphite surface.Such bulk and interphasial stability introduced by A12C4 leads to significantly improved cycling performance of LIBs.展开更多
Lithium bis(trifluoromethanesulfonyl)imide(Li-TFSI)/4-tert-butylpyridine(tBP)is a classic doping system for the hole transport material Spiro-OMeTAD in typical n-i-p structure perovskite solar cells(PSCs),but this sys...Lithium bis(trifluoromethanesulfonyl)imide(Li-TFSI)/4-tert-butylpyridine(tBP)is a classic doping system for the hole transport material Spiro-OMeTAD in typical n-i-p structure perovskite solar cells(PSCs),but this system will cause many problems such as high hygroscopicity,Li+migration,pinholes and so on,which hinder PSC from maintaining high efficiency and stability for long-term.In this work,an effective strategy is demonstrated to improve the performance and stability of PSC by replacing t BP with 12-crown-4.The chelation of 12-crown-4 with Li+not only improves the doping effect of Li-TFSI,but also perfectly solves the problems caused by the Li-TFSI/tBP system.The PSC based on this strategy achieved a champion power conversion efficiency(PCE)over 21%,which is significantly better than the pristine device(19.37%).More importantly,the without encapsulated device based on Li-TFSI/12-crown-4 still maintains 87%of the initial PCE even after 60 days exposure in air,while the pristine device only maintains 22%of the initial PCE under the same aging conditions.This strategy paves a novel way for constructing efficient and stable PSCs.展开更多
文摘Two novel heteroatom-bridged his (benzo-12-crown-4 ether)s, i.e. his [2-nitro-4,5 (1,4,7,10-tetraoxadecamethylene) disulfide 1 and diselenide 2, have been synthesized. X ray crystallographic structure was obtained for 1. Ion selective electrodes (ISE) for Ag+, containing 1 and 2 in PVC membrane as neutral carriers, were prepared, and their selectivity coefficients for Ag^+ (K_(Ag.M)^(pot)) were determined against other heavy metal ions, alkali and alkaline-earth metal ions. and ammonium ion. These ISEs showed excellent Ag^+ selectivities, log K_(Ag.M)^(pot) ≤ -3.8, against most of the interfering canons examined, except for Hg^+.
基金the National Natural Science Foundation of China (No. 20371040) the Foundation (031-A21-004)of Gansu province and the Foundation (No. 02-18) of Northwest Normal University.
文摘A new chiral multidenate ligand (S, S)-1,7-bis(4-benzyloxazolin-2-yl-methyl)-1, 7-diaza- 12-crown-4 1 has been synthesized and used as ligand in the copper catalyzed asymmetric cyclopropanation of 1, 1-diphenylethylene.
基金supported by the National Natural Science Foundation of China(21972049)the Guangdong Program for Distinguished Young Scholar(2017B030306013)the Science and Technology Planning Project of Guangdong Province(2017B090901020)。
文摘A once overlooked source of electrolyte degradation incurred by dissolved manganese(Ⅱ)species in lithium-ion batteries has been identified recently.In order to deactivate the catalytic activity of such manganese(II)ion,1-aza-12-crown-4-ether(A12C4)with cavity size well matched manganese(Ⅱ)ion is used in this work as electrolyte additive.Theoretical and experimental results show that stable complex forms between A12C4 and manganese(II)ions in the electrolyte,which does not affect the solvation of Li ions.The strong binding effect of A12C4 additive reduces the charge density of manganese(II)ion and inhibits its destruction of the PF_(6)^(-)structure in the electrolyte,leading to greatly improved thermal stability of manganese(II)ions-containing electrolyte.In addition to bulk electrolyte,A12C4 additive also shows capability in preventing Mn^(2+) from degrading SEI on graphite surface.Such bulk and interphasial stability introduced by A12C4 leads to significantly improved cycling performance of LIBs.
基金the National Natural Science Foundation of China(22175029 and 62104031)the Sichuan Science and Technology Program(2019YJ0162)+3 种基金the Open Foundation of State Key Laboratory of Electronic Thin Films and Integrated Devices(KFJJ202109)the Natural Science Foundation of Shenzhen Innovation Committee(JCYJ20210324135614040)the Technical Field Funds of 173 Project(2021-JCJQ-JJ-0663)the Fundamental Research Funds for the Central Universities of China(ZYGX2021J010 and Y030202059018023)for financial support。
文摘Lithium bis(trifluoromethanesulfonyl)imide(Li-TFSI)/4-tert-butylpyridine(tBP)is a classic doping system for the hole transport material Spiro-OMeTAD in typical n-i-p structure perovskite solar cells(PSCs),but this system will cause many problems such as high hygroscopicity,Li+migration,pinholes and so on,which hinder PSC from maintaining high efficiency and stability for long-term.In this work,an effective strategy is demonstrated to improve the performance and stability of PSC by replacing t BP with 12-crown-4.The chelation of 12-crown-4 with Li+not only improves the doping effect of Li-TFSI,but also perfectly solves the problems caused by the Li-TFSI/tBP system.The PSC based on this strategy achieved a champion power conversion efficiency(PCE)over 21%,which is significantly better than the pristine device(19.37%).More importantly,the without encapsulated device based on Li-TFSI/12-crown-4 still maintains 87%of the initial PCE even after 60 days exposure in air,while the pristine device only maintains 22%of the initial PCE under the same aging conditions.This strategy paves a novel way for constructing efficient and stable PSCs.
