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排序方式: 共有264条查询结果,搜索用时 31 毫秒
71.
Partha S. Ray Joan Buote Charles A. Webster Michael J. Manning 《Journal of heterocyclic chemistry》1993,30(1):45-48
Synthesis of pyridazino[1,2-a][1,2,4]benzotriazin-6-one derivatives involving reaction of either 1,2,3,6-tetra-hydropyridazine ( 9 ) or hexahydropyridazine 14 with 2-fluoro-5-nitrophenylisocyanate ( 5 ) to give, via intramolecular cyclization, 3a and 16 respectively is described. Compound 3a was converted to 18 via methylation and hydroxylation to give 20 followed by conversion to the acetonide derivative 18 . Both 16 and 18 were reduced to the amino derivatives 17 and 19 respectively. 相似文献
72.
Thomas J. Manning Brian Little Jerry Purcell Amy Feldman William Parker Katrice Register Brandy Sumner Clint Schibner 《The Chemical Educator》2002,7(5):278-283
The goal of this paper is to provide data that can be used in a variety of exercises ranging from kinetics in general chemistry to advanced problems in physical chemistry. The data provided relates to ozone-decay kinetics in various atmospheres (O2, N2, Ar) as measured by ultraviolet/visible absorbance spectroscopy (UV/vis) at 254 nm. The absorbance of ozone is monitored over a 75-min time period, and by using Beers law the concentration is calculated. Nine data sets, each repeated three times, of absorbance measurements are provided for student exercises, and prelaboratory and postlaboratory questions are suggested. 相似文献
73.
The reactions of [Fe2(η-C5H5)2(CO)2(L)(CNMe)] (L CO or CNME) with HgX2 (X Cl, Br or I) give [Fe(η-C5H5)(CO)2HgX] and [Fe(η-C5H5)(L)-(CNMe)X] as the sole products in ca. quantitative yields; this is consistent with the previously proposed mechanism for the reactions of electrophiles with polynuclear metal carbonyl derivatives. 相似文献
74.
Haiwen Zhang Jennifer E. Enman Maren L. Conrad Marcy J. Manning Courtney S. Turner Susan L. Wheaton Christopher M. Vogels Stephen A. Westcott Andreas Decken Felix J. Baerlocher 《Transition Metal Chemistry》2006,31(1):13-18
Pyridinecarboxaldimines (N–N′) derived from pyridin-2-ylcarboxaldehydes and unsaturated amines add to [PdCl2(coe)]2 (coe = cis-cyclooctene) to give complexes of the type PdCl2(N–N′) in moderate yields. The palladium complexes have been investigated as substrates for hydroboration reactions and as
antifungal agents against Aspergillus niger, A. flavus, Candida albicans, and Saccharomyces cerevisiae. 相似文献
75.
Aikaterini Vriza Angelos B. Canaj Rebecca Vismara Laurence J. Kershaw Cook Troy D. Manning Michael W. Gaultois Peter A. Wood Vitaliy Kurlin Neil Berry Matthew S. Dyer Matthew J. Rosseinsky 《Chemical science》2021,12(5):1702
The implementation of machine learning models has brought major changes in the decision-making process for materials design. One matter of concern for the data-driven approaches is the lack of negative data from unsuccessful synthetic attempts, which might generate inherently imbalanced datasets. We propose the application of the one-class classification methodology as an effective tool for tackling these limitations on the materials design problems. This is a concept of learning based only on a well-defined class without counter examples. An extensive study on the different one-class classification algorithms is performed until the most appropriate workflow is identified for guiding the discovery of emerging materials belonging to a relatively small class, that being the weakly bound polyaromatic hydrocarbon co-crystals. The two-step approach presented in this study first trains the model using all the known molecular combinations that form this class of co-crystals extracted from the Cambridge Structural Database (1722 molecular combinations), followed by scoring possible yet unknown pairs from the ZINC15 database (21 736 possible molecular combinations). Focusing on the highest-ranking pairs predicted to have higher probability of forming co-crystals, materials discovery can be accelerated by reducing the vast molecular space and directing the synthetic efforts of chemists. Further on, using interpretability techniques a more detailed understanding of the molecular properties causing co-crystallization is sought after. The applicability of the current methodology is demonstrated with the discovery of two novel co-crystals, namely pyrene-6H-benzo[c]chromen-6-one (1) and pyrene-9,10-dicyanoanthracene (2).Machine learning using one class classification on a database of existing co-crystals enables the identification of co-formers which are likely to form stable co-crystals, resulting in the synthesis of two co-crystals of polyaromatic hydrocarbons. 相似文献
76.
Anthony Manning 《Proceedings of the American Mathematical Society》2005,133(6):1693-1697
Suppose that and are axiom A flows with attractors and . Then the attractor for the product flow on the product manifold is no longer hyperbolic (although there is a hyperbolic action of ).
It is easy to see that the attractor cannot explode but we show here that it cannot implode: for any flow sufficiently close to any attractor whose basin is not too thin is -dense in .
77.
78.
The sole and unexpected products from the reactions of a variety of lead (II) and lead (IV) compounds with [Co2(CO)6(L)2] complexes (L = tertiary arsine, phosphine, or phosphite) in refluxing benzene solution are the blue, air-stable percobaltoplumbanes [Pb{Co(CO)3(L)}4]. These have also been obtained from the reaction of Na[Co(CO)3(L)] (L PBu3n) with lead (II) acetate which with Na[Fe(CO)2(NO)(L)] forms the isoelectronic [Pb{Fe(CO)2(NO)(L)}4] [L P(OPh)3]. The IR spectra of the complexes in the v(CO) and v(NO) regions are consistent with tetrahedral PbCo4 or PbFe4 fragments, trigonal bipyramidal coordination about the cobalt or iron atoms and linear PbCoAs, PbCoP, or PbFeP systems. Unlike [Pb{Co(CO)4}4], our complexes do not dissociate to [Co(CO)3(L)]? or [Fe(CO)2(NO)(L)]? ions when dissolved in donor solvents. 相似文献
79.
D.C. Manning Walter Slavin G.R. Carnrick 《Spectrochimica Acta Part B: Atomic Spectroscopy》1982,37(4):331-341
Al was determined in the stabilized temperature platform furnace with very few interferences. No interferences were found for several metal nitrates, sulfates or phosphates, or for NaCl. The Al absorbance signal was delayed in the presence of MgCl2 but there was no interference. This led to the use of 50 μg Mg(NO3)2 as a matrix modifier for Al. There were no interferences for CaCl2 but it was particularly important to use new pyrolytically coated tubes to avoid “aging” effects. CuCl2 provided a very persistent interference that was reduced when the Mg(NO3)2 matrix modifier was used that permitted a char temperature of 1700°C. Perchloric acid interferences were severe with improperly coated graphite tubes but did not exist up to 0.5 M HClO4 when the new pyrolytically coated tubes were used. A serum Al method was tested briefly and no problems were found. Al was determined in seawater with no influence from the salinity of the sample and less than 0.6 μg/1 Al in seawater could be detected. 相似文献
80.