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排序方式: 共有575条查询结果,搜索用时 15 毫秒
1.
Agarwal Madhu Kuldeep Brijesh John Annie P. Maheshwari Karishma Dohare Rajeev 《Journal of Thermal Analysis and Calorimetry》2022,147(13):7243-7252
Journal of Thermal Analysis and Calorimetry - In this study, beeswax is studied as a phase change material (PCM) to store heat due to its high latent heat. The disadvantages of using beeswax were... 相似文献
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Metal–organic frameworks (MOFs) are emerging porous coordination polymers constructed by metal ions and organic linkers that have attracted numerous interests in recent years. The large surface area, high porosity, tunable size, and versatile functionality make them promising materials for cargo delivery (i.e., drugs, mRNA, dyes) and sensing (i.e., nucleic acids, small molecules, ions). In addition, the metal ions released from MOFs offer antibacterial and antifungal utility. This review presents a snapshot of current MOF-related research, highlighting the synthesis approaches, and the various bioapplications of MOFs in terms of biosensing platforms, drug delivery, and antimicrobial agents, exposing potential for future research in the MOF field. 相似文献
4.
Rouven F. Pfleger Sören Schlittenhardt Dr. Marcel P. Merkel Prof. Dr. Mario Ruben Prof. Dr. Karin Fink Dr. Christopher E. Anson Prof. Jesper Bendix Prof. Dr. Annie K. Powell 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(61):15086-15095
We report three structurally related single ion Dy compounds using the pentadentate ligand 2,6-bis((E)-1-(2-(pyridin-2-yl)-hydrazineylidene)ethyl)pyridine (H2dapp) [Dy(H2dapp)(NO3)2]NO3 ( 1 ), [Dy(H2dapp)(OAc)2]Cl ( 2 ) and [Dy(H2dapp)(NO3)2]Cl0.92(NO3)0.08 ( 3 ). The (H2dapp) occupies a helical twisted pentagonal equatorial arrangement with two anionic ligands in the axial positions. Further influence on the electronic and magnetic structure is provided by a closely associated counterion interacting with the central N−H group of the (H2dapp). The slow relaxation of the magnetisation shows that the anionic acetates give the greatest slowing down of the magnetisation reversal. Further influence on the relaxation properties of compounds 1 and 2 is the presence of short nitrate-nitrate intermolecular ligand contact opening further lattice relaxation pathways. 相似文献
5.
A Bis‐Sulfonyl O,C,O Aryl Pincer Ligand and its Tin(II) Complex: Synthesis,Structural Studies,and DFT Calculations 下载免费PDF全文
Mohammad El Ezzi Romaric Lenk Dr. David Madec Dr. Jean‐Marc Sotiropoulos Sonia Mallet‐Ladeira Dr. Annie Castel 《Angewandte Chemie (International ed. in English)》2015,54(3):805-808
The efficiency of the deprotonated aryl bis‐sulfone [2,6‐{(p‐tolyl)SO2}2C6H3]? as an O,C,O‐coordinating pincer‐type ligand was described. The bis‐sulfone precursor was synthesized using a straightforward palladium‐catalyzed cross‐coupling reaction. As a result of directed ortho metalation (DoM) through sulfonyl groups, a selective lithiation of the aryl group was achieved and the corresponding carbanion was isolated and its structure determined by single‐crystal X‐ray diffraction analysis. A heteroleptic tin(II) complex has been prepared by a nucleophilic substitution reaction. Crystallographic analysis and DFT calculations indicate that the bis‐sulfonyl moiety acts as a new O,C,O‐coordinating pincer‐type ligand with intramolecular S?O coordination to a tin(II) center. The cis form with the two nonbonded oxygen atoms of the sulfonyl groups on the same side is preferentially obtained. 相似文献
6.
Stereoselective Synthesis of the Halaven C14–C26 Fragment from D‐Quinic Acid: Crystallization‐Induced Diastereoselective Transformation of an α‐Methyl Nitrile 下载免费PDF全文
Francis Belanger Dr. Charles E. Chase Dr. Atsushi Endo Dr. Francis G. Fang Dr. Jing Li Steven R. Mathieu Dr. Annie Z. Wilcoxen Huiming Zhang 《Angewandte Chemie (International ed. in English)》2015,54(17):5108-5111
Crystallization‐induced diastereoselective transformation (CIDT) of an α‐methyl nitrile completes an entirely non‐chromatographic synthesis of the halichondrin B C14–C26 stereochemical array. The requisite α‐methyl nitrile substrate is derived from D ‐quinic acid through a series of substrate‐controlled stereoselective reactions via a number of crystalline intermediates that benefit from a rigid polycyclic template. Therefore, all four stereogenic centers in the Halaven C14–C26 fragment were derived from the single chiral source D ‐quinic acid. 相似文献
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Self‐Assembly of a Giant Tetrahedral 3 d–4 f Single‐Molecule Magnet within a Polyoxometalate System 下载免费PDF全文
Dr. Masooma Ibrahim Dr. Valeriu Mereacre Dr. Nicolas Leblanc Prof. Wolfgang Wernsdorfer Dr. Christopher E. Anson Prof. Annie K. Powell 《Angewandte Chemie (International ed. in English)》2015,54(51):15574-15578
A giant tetrahedral heterometallic polyoxometalate (POM) [Dy30Co8Ge12W108O408(OH)42(OH2)30]56?, which shows single‐molecule magnet (SMM) behavior, is described. This hybrid contains the largest number of 4f ions of any polyoxometalate (POM) reported to date and is the first to incorporate two different 3d–4f and 4f coordination cluster assemblies within same POM framework. 相似文献
8.
Annie Burns-Childers Draga Vidakovic 《International Journal of Mathematical Education in Science & Technology》2018,49(5):660-679
The purpose of this study was to gain insight into 30, first year calculus students’ understanding of the relationship between the concept of vertex of a quadratic function and the concept of the derivative. APOS (action-process-object-schema) theory was applied as a guiding framework of analysis on student written work, think-aloud and follow up group interviews. Students’ personal meanings of the vertex, including misconceptions, were explored, along with students’ understanding to solve problems pertaining to the derivative of a quadratic function. Results give evidence of students’ weak schema of the vertex, lack of connection between different problem types and the importance of linguistics in relation to levels of APOS theory. A preliminary genetic decomposition was developed based on the results. Future research is suggested as a continuation to improve student understanding of the relationship between the vertex of quadratic functions and the derivative. 相似文献
9.
Dr. Dominique T. Thielemann Anna T. Wagner Dr. Yanhua Lan Dr. Pascual Oña‐Burgos Prof. Dr. Ignacio Fernández Prof. Dr. Esther S. Rösch Dr. Dominik K. Kölmel Prof. Dr. Annie K. Powell Prof. Dr. Stefan Bräse Prof. Dr. Peter W. Roesky 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(7):2813-2820
A new family of pentadecanuclear coordination cluster compounds (from now on simply referred to as clusters) [{Ln15(OH)20(PepCO2)10(DBM)10Cl}Cl4] (PepCO2=2‐[{3‐(((tert‐butoxycarbonyl)amino)methyl)benzyl}amino]acetate, DBM=dibenzoylmethanide) with Ln=Y and Dy was obtained by using the cell‐penetrating peptoid (CPPo) monomer PepCO2H and dibenzoylmethane (DBMH) as supporting ligands. The combination of an inorganic cluster core with an organic cell‐penetrating peptoid in the coordination sphere resulted in a core component {Ln15(μ3‐OH)20Cl}24+ (Ln=Y, Dy), which consists of five vertex‐sharing heterocubane {Ln4(μ3‐OH)4}8+ units that assemble to give a pentagonal cyclic structure with one Cl atom located in the middle of the pentagon. The solid‐state structures of both clusters were established by single‐crystal X‐ray crystallography. MS (ESI) experiments suggest that the cluster core is robust and maintained in solution. Pulsed gradient spin echo (PGSE) NMR diffusion measurements were carried out on the diamagnetic yttrium compound and confirmed the stability of the cluster in its dicationic form [{Y15(μ3‐OH)20(PepCO2)10(DBM)10Cl}Cl2]2+. The investigation of both static (dc) and dynamic (ac) magnetic properties in the dysprosium cluster revealed a slow relaxation of magnetization, indicative of single‐molecule magnet (SMM) behavior below 8 K. Furthermore, the χT product as a function of temperature for the dysprosium cluster gave evidence that this is a ferromagnetically coupled compound below 11 K. 相似文献
10.
Amily Fang-ju Jou Chun-Hua Lu Yen-Chuan Ou Shian-Shiang Wang Shih-Lan Hsu Itamar Willner Ja-an Annie Ho 《Chemical science》2015,6(1):659-665
The microRNA, miR-141, is a promising biomarker for prostate cancer. We implement here a two-step sensing platform for the sensitive detection of miR-141. The first step involves the use of semiconductor CdSe/ZnS quantum dots (QDs) modified by FRET quencher-functionalized nucleic acids, that include the recognition sequence for miR-141 and a telomerase primer sequence for the second step of the analytical platform. Subjecting the probe-modified QDs to miR-141, in the presence of duplex specific nuclease, DSN, leads to the formation of a miR-141/probe duplex and to its DSN-mediated cleavage, while regenerating the miR-141. The DSN-induced cleavage of the quencher units leads to the activation of the fluorescence of the QDs, thus allowing the optical detection of miR-141 with a sensitivity corresponding to 1.0 × 10–12 M. The nucleic acid residues associated with the QDs after cleavage of the probe nucleic acids by DSN act as primers for telomerase. The subsequent telomerase/dNTPs-stimulated elongation of the primer units forms G-quadruplex telomer chains. Incorporation of hemin in the resulting G-quadruplex telomer chains yields horseradish peroxidase-mimicking DNAzyme units, that catalyze the generation of chemiluminescence in the presence of luminol/H2O2. The resulting chemiluminescence intensities provide a readout signal for miR-141, DL = 2.8 × 10–13 M. The first step of the sensing platform is non-selective toward miR-141 and the resulting fluorescence may be considered only as an indicator for the existence of miR-141. The second step in the sensing protocol, involving telomerase, provides a selective chemiluminescence signal for the existence of miR-141. The two-step sensing platform is implemented for the analysis of miR-141 in serum samples from healthy individuals and prostate cancer carriers. Impressive discrimination between healthy individuals and prostate cancer carriers is demonstrated. 相似文献