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961.
Zhihong Liu Minghao Zheng Xin Yan Qiong Gu Johann Gasteiger Johan Tijhuis Peter Maas Jiabo Li Jun Xu 《Journal of computer-aided molecular design》2014,28(9):941-950
Predicting compound chemical stability is important because unstable compounds can lead to either false positive or to false negative conclusions in bioassays. Experimental data (COMDECOM) measured from DMSO/H2O solutions stored at 50 °C for 105 days were used to predicted stability by applying rule-embedded naïve Bayesian learning, based upon atom center fragment (ACF) features. To build the naïve Bayesian classifier, we derived ACF features from 9,746 compounds in the COMDECOM dataset. By recursively applying naïve Bayesian learning from the data set, each ACF is assigned with an expected stable probability (p s ) and an unstable probability (p uns ). 13,340 ACFs, together with their p s and p uns data, were stored in a knowledge base for use by the Bayesian classifier. For a given compound, its ACFs were derived from its structure connection table with the same protocol used to drive ACFs from the training data. Then, the Bayesian classifier assigned p s and p uns values to the compound ACFs by a structural pattern recognition algorithm, which was implemented in-house. Compound instability is calculated, with Bayes’ theorem, based upon the p s and p uns values of the compound ACFs. We were able to achieve performance with an AUC value of 84 % and a tenfold cross validation accuracy of 76.5 %. To reduce false negatives, a rule-based approach has been embedded in the classifier. The rule-based module allows the program to improve its predictivity by expanding its compound instability knowledge base, thus further reducing the possibility of false negatives. To our knowledge, this is the first in silico prediction service for the prediction of the stabilities of organic compounds. 相似文献
962.
963.
以甲醇为溶剂,将异马来二氰基二硫烯酸钾[K2(i-mnt)]和六水氯化镍分别与溴化4-溴苄基喹啉盐([4-BrBzQl]Br)或溴化4-硝基苄基喹啉盐([4-NO2BzQl]Br)直接反应,得到两种新的离子对配合物[4-BrBzQl]2[Ni(i-mnt)2](1)和[4-NO2BzQl]2[Ni(i-mnt)2](2);测定了其红外光谱和紫外-可见光谱,并利用X射线衍射表征了配合物1的晶体结构.结果表明,配合物[4-BrBzQl]2[Ni(i-mnt)2]为三斜晶系,P-1空间群,其每个不对称单元含半个[Ni(i-mnt)2]2-阴离子和1个[4-BrBzQl]+阳离子,晶体中的阴、阳离子通过静电作用和C-H…S、C-H…N氢键作用形成网络结构. 相似文献
964.
研究了南美白对虾苗中4种硝基呋喃代谢物呋喃唑酮代谢物(AOZ)、呋喃它酮代谢物(AMOZ)、呋喃妥因代谢物(AHD)、呋喃西林代谢物(SEM)的高效液相色谱–串联质谱(HPLC–MS/MS)测定方法。以水解衍生并添加4种同位素内标的方法对样品进行处理,补偿了衍生化效率,提高了定量的准确性。实验结果表明,AOZ,AMOZ的检出限为0.10μg/kg,SEM,AHD的检出限为0.25μg/kg;AOZ,AMOZ的定量下限为0.40μg/kg,SEM,AHD的定量下限为0.50μg/kg。方法加标回收率在88.2%~97.6%之间,相对标准偏差在4.6%~8.1%(n=6)之间。该法检测灵敏度高,测量结果的精密度和准确度满足药物残留检测要求。 相似文献
965.
Dr. Huizeng Li Wei Fang Zhipeng Zhao An Li Dr. Zheng Li Prof. Mingzhu Li Prof. Qunyang Li Prof. Xiqiao Feng Prof. Yanlin Song 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(26):10622-10626
Precise separation and localization of microdroplets are fundamental for various fields, such as high-throughput screening, combinatorial chemistry, and the recognition of complex analytes. We have developed a droplet self-splitting strategy to divide an impacting droplet into predictable microdroplets and deposit them at preset spots for simultaneous multidetection. No matter exchange was observed between these microdroplets, so they could be manipulated independently. Droplet self-splitting was attributed to anisotropic liquid recoiling on the patterned adhesive surface, as influenced by the droplet Weber number and the width of the low-adhesive stripe. A quantitative criterion was also developed to judge the droplet self-splitting capability. The precise separation and distribution of microdroplets enabled simultaneous arrayed reactions and multiple analyte detection using one droplet of sample. 相似文献
966.
Shuyuan Zheng Tianwen Zhu Yunzhong Wang Tianjia Yang Prof. Wang Zhang Yuan 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(25):10104-10108
Nonaromatic, cross-conjugated, and highly twisted luminogens consisting of acylated succinimides demonstrate aggregation-induced emission characteristics along with tunable multicolor photoluminescence and afterglows in their single crystals. Effective through-space conjugation among different moieties bearing n/π electrons promote the spin–orbit coupling and intersystem crossing and lead to diverse emissive clusters with concurrently rigidified conformations, thus allowing readily tunable emissions. Derived from it, the proof-of-concept application for advanced anti-counterfeiting is illustrated. These results should spur the rational design of novel nonaromatic AIEgens, and moreover advance understandings of the non-traditional intrinsic luminescence and the origin of tunable multicolor afterglows. 相似文献
967.
Dr. Chun-Chao Hou Dr. Lianli Zou Dr. Liming Sun Dr. Kexin Zhang Dr. Zheng Liu Prof. Yinwei Li Dr. Caixia Li Prof. Ruqiang Zou Prof. Jihong Yu Prof. Qiang Xu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(19):7454-7459
Single-atom catalysts have drawn great attention, especially in electrocatalysis. However, most of previous works focus on the enhanced catalytic properties via improving metal loading. Engineering morphologies of catalysts to facilitate mass transport through catalyst layers, thus increasing the utilization of each active site, is regarded as an appealing way for enhanced performance. Herein, we design an overhang-eave structure decorated with isolated single-atom iron sites via a silica-mediated MOF-templated approach for oxygen reduction reaction (ORR) catalysis. This catalyst demonstrates superior ORR performance in both alkaline and acidic electrolytes, comparable to the state-of-the-art Pt/C catalyst and superior to most precious-metal-free catalysts reported to date. This activity originates from its edge-rich structure, having more three-phase boundaries with enhanced mass transport of reactants to accessible single-atom iron sites (increasing the utilization of active sites), which verifies the practicability of such a synthetic approach. 相似文献
968.
Dr. Zheng Deng Dr. Chang-Jong Kang Prof. Dr. Mark Croft Dr. Wenmin Li Dr. Xi Shen Dr. Jianfa Zhao Prof. Dr. Richeng Yu Prof. Dr. Changqing Jin Prof. Dr. Gabriel Kotliar Dr. Sizhan Liu Prof. Dr. Trevor A. Tyson Dr. Ryan Tappero Prof. Dr. Martha Greenblatt 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(21):8317-8323
Given the consensus that pressure improves cation ordering in most of known materials, a discovery of pressure-induced disordering could require recognition of an order–disorder transition in solid-state physics/chemistry and geophysics. Double perovskites Y2CoIrO6 and Y2CoRuO6 polymorphs synthesized at 0, 6, and 15 GPa show B-site ordering, partial ordering, and disordering, respectively, accompanied by lattice compression and crystal structure alteration from monoclinic to orthorhombic symmetry. Correspondingly, the long-range ferrimagnetic ordering in the B-site ordered samples are gradually overwhelmed by B-site disorder. Theoretical calculations suggest that unusual unit-cell compressions under external pressures unexpectedly stabilize the disordered phases of Y2CoIrO6 and Y2CoRuO6. 相似文献
969.
Qingyun Zheng Tian Wang Guo-Chao Chu Chong Zuo Rui Zhao Xin Sui Linzhi Ye Yuanyuan Yu Jingnan Chen Xiangwei Wu Wenhao Zhang Prof. Haiteng Deng Prof. Jing Shi Dr. Man Pan Prof. Yi-Ming Li Prof. Lei Liu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(32):13598-13603
Triazole-based deubiquitylase (DUB)-resistant ubiquitin (Ub) probes have recently emerged as effective tools for the discovery of Ub chain-specific interactors in proteomic studies, but their structural diversity is limited. A new family of DUB-resistant Ub probes is reported based on isopeptide-N-ethylated dimeric or polymeric Ub chains, which can be efficiently prepared by a one-pot, ubiquitin-activating enzyme (E1)-catalyzed condensation reaction of recombinant Ub precursors to give various homotypic and even branched Ub probes at multi-milligram scale. Proteomic studies using label-free quantitative (LFQ) MS indicated that the isopeptide-N-ethylated Ub probes may complement the triazole-based probes in the study of Ub interactome. Our study highlights the utility of modern protein synthetic chemistry to develop structurally and new families of tool molecules needed for proteomic studies. 相似文献
970.
Peng-Bo Jin Yuan-Qi Zhai Ke-Xin Yu Prof. Dr. Richard E. P. Winpenny Prof. Dr. Yan-Zhen Zheng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(24):9436-9440
The dicarbollide ion, nido-C2B9H112− is isoelectronic with cyclopentadienyl. Herein, we make dysprosiacarboranes, namely [(C2B9H11)2Ln(THF)2][Na(THF)5] (Ln=Dy, 1Dy ) and [(THF)3(μ-H)3Li]2[{η5-C6H4(CH2)2C2B9H9}Dy{η2:η5-C6H4(CH2)2C2B9H9}2Li] 3Dy and show that dicarbollide ligands impose strong magnetic axiality on the central DyIII ion. The effective energy barrier (Ueff) for the loss of magnetization can be varied by the substitution pattern on the dicarbollide. This finding is demonstrated by comparing complexes of nido-C2B9H112− and nido-[o-xylylene-C2B9H9]2−, which show a Ueff of 430(5) K and 804(7) K, respectively. The blocking temperature defined by the open hysteresis temperature of 3Dy reaches 6.8 K. Moreover, the linear complex [Dy(C2B9H11)2]− is predicted to have comparable properties with the linear [Dy(CpMe3)2]+ complex. As such, carboranyl ligands and their derivatives may provide a new type of organometallic ligand for high-performance single-molecule magnets. 相似文献