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91.
Johannes Kretsch Anne-Kathrin Kreyenschmidt Timo Schillmöller Dr. Märt Lõkov Dr. Regine Herbst-Irmer Prof. Dr. Ivo Leito Prof. Dr. Dietmar Stalke 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(38):9858-9865
A novel sterically demanding bis(4-benzhydryl-benzoxazol-2-yl)methane ligand 6 (4−BzhH2BoxCH2) was gained in a straightforward six-step synthesis. Starting from this ligand monomeric [M(4-BzhH2BoxCH)] (M=Na ( 7 ), K ( 81 )) and dimeric [{M(4-BzhH2BoxCH)}2] (M=K ( 82 ), Rb ( 9 ), Cs ( 10 )) alkali metal complexes were synthesised by deprotonation. Abstraction of the potassium ion of 8 by reaction with 18-crown-6 resulted in the solvent separated ion pair [{(THF)2K@(18-crown-6)}{bis(4-benzhydryl-benzoxazol-2-yl)methanide}] ( 11 ), including the energetically favoured monoanionic (E,E)-(4-BzhH2BoxCH) ligand. Further reaction of 4−BzhH2BoxCH2 with three equivalents KH and two equivalents 18-crown-6 yielded polymeric [{(THF)2K@(18-crown-6)}{K@(18-crown-6)K(4-BzhBoxCH)}]n (n→∞) ( 12 ) containing a trianionic ligand. The neutral ligand and herein reported alkali complexes were characterised by single X-ray analyses identifying the latter as a promising precursor for low-valent main group complexes. 相似文献
92.
利用和频光谱技术详细研究了磷酸钾缓冲溶液与带负电荷的生物仿生膜(d54-DMPG磷脂双层膜)相互作用的实时过程.通过监控CD2、CD3、磷脂分子头部的磷酸根以及羰基官能团的光谱信号随加入磷酸钾缓冲溶液的实时变化,获得了磷脂双层膜分子结构的动力学变化.结果表明K+能够结合到细胞膜上,并且很快地引起了CD2、CD3、磷脂头部磷酸根以及羰基官能团信号的变化.根据各官能团的和频信号响应,磷酸钾缓冲溶液很可能是通过在双层膜中形成环形气孔来与磷脂双层膜发生作用.该结果可以很好地解释磷酸钾缓冲溶液环境下的离子协助蛋白质的跨膜过程. 相似文献
93.
Facile Preparation of α‐Zirconium Phosphate/Polyaniline Hybrid Film for Detecting Potassium Ion in a Wide Linear Range 下载免费PDF全文
Yanhong Wang Chunfeng Xue Xiumin Li Xiao Du Zhongde Wang Guozhang Ma Xiaogang Hao 《Electroanalysis》2014,26(2):416-423
A novel α‐zirconium phosphate/polyaniline (α‐ZrP/PANI) hybrid film used as K+ ion sensor was fabricated on carbon paper by electrochemical method. Mechanisms of film formation and detection of K+ ions were also proposed. The exfoliated α‐ZrP was mixed with PANI and deposited on carbon paper. The resultant α‐ZrP/PANI film exhibited a good current response to K+ ion with different concentrations. It also showed a wide logarithmic linear response in detecting K+ ions in the ranges of 10?8–10?4 M and 10?4–10?2 M, respectively. The results can be attributed to the synergetic effect of α‐ZrP and PANI. 相似文献
94.
An efficient synthesis of Biginelli-type compounds using potassium phthalimide as a green, mild, and commercially available organocatalyst in a one-pot, multi-component cyclocondensation reaction of cyclopentanone, aldehydes, and urea/thiourea is reported. The present methodology is a green approach to access 4-aryl-7-(aryImethylene)-3,4,6,7-tetrahydro-1H-cyclopenta[d]pyrimidin-2(5H)-ones/thiones. It offers several merits such as simple operational procedures, no use of hazardous organic solvents, and cheap and environmentally friendly solid basic catalyst. 相似文献
95.
采用等体积浸渍法制备了Cu-K-La/γ-Al2O3催化剂,考察了KCl对该催化剂催化HCl氧化制Cl2反应性能的影响. 当KCl的负载量为5 wt%时,Cu-K-La/γ-Al2O3催化剂表现出较好的催化活性和稳定性,可在较大的原料气空速变化范围内使用. 在0.1 MPa,360 ℃,空速450 L/(kg-cat·h)和HCl/O2摩尔比为2:1的反应条件下,Cu-K-La/γ-Al2O3催化剂上HCl转化率在100 h内保持85%以上. 表征结果表明,Cu,K和La物种均高度分散于γ-Al2O3载体表面;一定量KCl的加入可降低Cu2+ → Cu+的还原温度,从而提高Cu2+活性中心的催化活性. 相似文献
96.
97.
Litao Zhao Fanghong Luo Anting Wang Jing Zhang Yuanhang Wang Liangtao Zhao Zhaoyan Wang Qiaosheng Pu 《Electrophoresis》2020,41(15):1273-1279
Mutations in the potassium channel genes may be linked to the development of epilepsy and affect the blood potassium levels. Therefore, accurate determination of potassium in the blood will be critical to diagnose the cause of epilepsy. CE is a competent technique for the fast detection of multiple ions, but complicated matrices of a blood sample may cause significant variation of migration times and the peak shape. In this work, a procedure for rapid stabilization of the capillary inner surface through preflushing of a blood sample was employed. The process takes only 40 min for a capillary and then it can be used for more than 2 weeks. No pretreatment of the blood sample or other surface modification of the capillary is needed for the analysis. The RSDs of the migration time and peak area were reduced to 1.5 and 5.1% from 12.6 and 14.5%, respectively. The proposed method has been successfully applied to the determination of the potassium contents in the blood sample of patients with epilepsy at different stages. The recoveries of potassium ions in these blood samples are in a range from 86.5 to 104.5%. 相似文献
98.
A pilot plant study of the radiation grafting of styrene to polyvinyl chloride) (PVC) latex is described. When correct extraction conditions are used less than 3% grafting took place. This is shown to be due to the low total radiation doses needed to polymerize the styrene in an emulsion system. A parallel study with PVC film did, however, lead to substantial true grafting. The G (radical) value for PVC film as determined by ESR was found to be 4.6. 相似文献
99.
A solid state metathesis (SSM) reaction was investigated with respect to the formation of rare‐earth carbodiimides, the role of the co‐produced salt (LiCl), and the eutectic flux medium (LiCl/KCl). A SSM reaction is characterized by an exothermic reaction in which a salt (often LiCl) is coproduced. When the salt melts, it can serve as a useful medium for the crystallization of a desired product. An improved crystal growth can be observed by using an eutectic flux. However, the composition of an eutectic LiCl/KCl flux is altered when LiCl is produced during the reaction. The thermal effects concerning the endothermic melting of the flux and the exothermic ingnition of the SSM reaction may compensate each other, which is not necessarily a drawback for the reaction to proceed. 相似文献
100.
Zbigniew GrobelnyAndrzej Stolarzewicz Barbara Morejko-Bu?Adalbert Maercker 《Journal of organometallic chemistry》2002,660(1):6-13
The linear ether bond was exclusively cleaved in benzyl glycidyl ether and triphenylmethyl glycidyl ether under the influence of K−, K+(15-crown-5)2 (1), whereas the strongly strained three-membered oxacyclic ring remained undisturbed. Potassium glycidoxide and benzylpotassium were found as the primary reaction products of benzyl glycidyl ether with 1. Subsequently, benzylpotassium reacted with benzyl glycidyl ether giving the next potassium glycidoxide molecule and bibenzyl. Benzyl phenyl ether was used as a model compound to explain the mechanism of bibenzyl formation. The reaction of triphenylmethyl glycidyl ether with 1 resulted in potassium glycidoxide and stable triphenylmethylpotassium. After treating with a quenching agent a new glycidyl ether or glycidyl ester was obtained from potassium glycidoxide. These results were found when the reaction occurred at the excess of glycidyl ether. In another case, i.e. at the excess of 1 further reactions took place with the participation of potassium anions and various new compounds were observed in the reaction mixture after benzylation or methylation. Thus, the method of substrates delivery influences the course of studied processes in a decisive way. 相似文献