排序方式: 共有54条查询结果,搜索用时 93 毫秒
31.
Unsaturated N-chloroamines have been found to cyclise under palladium-catalysis in good yield, the proposed mechanism includes an oxidative addition of the chloroamine to Pd(0), thus opening a new entry to the amides of the late transition metals. 相似文献
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Juho Heiska Dr. Olli Sorsa Prof. Tanja Kallio Prof. Maarit Karppinen 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(34):8799-8803
Two new atomic/molecular layer deposition processes for depositing crystalline metal-organic thin films, built from 1,4-benzenedisulfonate (BDS) as the organic linker and Cu or Li as the metal node, are reported. The processes yield in-situ crystalline but hydrated Cu-BDS and Li-BDS films; in the former case, the crystal structure is of a previously known metal-organic-framework-like structure, while in the latter case not known from previous studies. Both hydrated materials can be readily dried to obtain the crystalline unhydrated phases. The stability and the ionic conductivity of the unhydrated Li-BDS films were characterized to assess their applicability as a thin film solid polymer Li-ion conductor. 相似文献
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Aleksandar R. Todorov Dr. Martin Nieger Dr. Juho Helaja 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(23):7269-7277
Novel 4‐hydroxyquinoline (4HQ) based tautomeric switches are reported. 4HQs equipped with coordinative side arms (8‐arylimino and 3‐piperidin‐1‐ylmethyl groups) were synthesized to access O‐ or N‐selective chelation of Zn2+ and Cd2+ ions by 4HQ. In the case of the monodentate arylimino group, O chelation of metal ions induces concomitant switching of phenol tautomer to the keto form in nonpolar or aprotic media. This change is accompanied by selective and highly sensitive fluorometric sensing of Zn2+ ions. In the case of the bidentate 8‐(quinolin‐8‐ylimino)methyl side arm, NMR studies in CD3OD indicated that both Cd2+ and Zn2+ ions afford N chelation for 4HQ, coexisting with tautomeric switching from quinolin‐4(1H)‐one to quinolin‐4‐olate. In corroboration, UV/Vis‐monitored metal‐ion titrations in toluene and methanol implied similar structural changes. Additionally, fluorescence measurements indicated that the metal‐triggered tautomeric switching is associated with compound signaling properties. The results are supported by DFT calculations at the B3LYP 6‐31G* level. Several X‐ray structures of metal‐free and metal‐chelating 4HQ are presented to support the solution studies. 相似文献
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Todorov AR Nieger M Helaja J 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(23):7269-7277
Novel 4-hydroxyquinoline (4HQ) based tautomeric switches are reported. 4HQs equipped with coordinative side arms (8-arylimino and 3-piperidin-1-ylmethyl groups) were synthesized to access O- or N-selective chelation of Zn(2+) and Cd(2+) ions by 4HQ. In the case of the monodentate arylimino group, O chelation of metal ions induces concomitant switching of phenol tautomer to the keto form in nonpolar or aprotic media. This change is accompanied by selective and highly sensitive fluorometric sensing of Zn(2+) ions. In the case of the bidentate 8-(quinolin-8-ylimino)methyl side arm, NMR studies in CD(3) OD indicated that both Cd(2+) and Zn(2+) ions afford N chelation for 4HQ, coexisting with tautomeric switching from quinolin-4(1H)-one to quinolin-4-olate. In corroboration, UV/Vis-monitored metal-ion titrations in toluene and methanol implied similar structural changes. Additionally, fluorescence measurements indicated that the metal-triggered tautomeric switching is associated with compound signaling properties. The results are supported by DFT calculations at the B3LYP 6-31G* level. Several X-ray structures of metal-free and metal-chelating 4HQ are presented to support the solution studies. 相似文献
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Juho Kanniainen 《Operations Research Letters》2011,39(4):260-264
This paper proposes a unified framework for option pricing, which integrates the stochastic dynamics of interest rates, dividends, and stock prices under the transversality condition. Using the Vasicek model for the spot rate dynamics, I compare the framework with two existing option pricing models. The main implication is that the stochastic spot rate affects options not only directly but also via an endogenously determined dividend yield and return volatility; consequently, call prices can be decreasing with respect to interest rates. 相似文献
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A chemoselective aminolysis of the β-keto ester of pheophorbide a methyl ester is demonstrated opening a facile access to an asymmetric amide functionalization of a chlorin ring using a range of aromatic and aliphatic, primary and secondary amine nucleophiles. Aminolysis of pheophorbide a methyl ester with trans-1,2-diaminocyclohexane is shown to give a symmetric open face chlorin dimer. 相似文献
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David S. Casadio Dr. Santeri Aikonen Dr. Anna Lenarda Dr. Martin Nieger Dr. Tao Hu Dr. Stefan Taubert Prof. Dage Sundholm Dr. Mikko Muuronen Dr. Tom Wirtanen Dr. Juho Helaja 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(16):5283-5291
Mildly thermal air or HNO3 oxidized activated carbons catalyse oxidative dehydrogenative couplings of benzo[b]fused heteroaryl 2,2’-dimers, e.g., 2-(benzofuran-2-yl)-1H-indole, to chiral 3,3’-coupled cyclooctatetraenes or carbazole-type migrative products under O2 atmosphere. DFT calculations show that the radical cation and the Scholl-type arenium cation mechanisms lead to different products with 2-(benzofuran-2-yl)-1H-indole, being in accord with experimental product distributions. 相似文献
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Dr. Tom Wirtanen Santeri Aikonen Dr. Mikko Muuronen Dr. Michele Melchionna Dr. Marianna Kemell Fatemeh Davodi Prof. Tanja Kallio Dr. Tao Hu Dr. Juho Helaja 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(53):12288-12293
HNO3-oxidized carbon nanotubes catalyze oxidative dehydrogenative (ODH) carbon–carbon bond formation between electron-rich (hetero)aryls with O2 as a terminal oxidant. The recyclable carbocatalytic method provides a convenient and an operationally easy synthetic protocol for accessing various benzofused homodimers, biaryls, triphenylenes, and related benzofused heteroaryls that are highly useful frameworks for material chemistry applications. Carbonyls/quinones are the catalytically active site of the carbocatalyst as indicated by model compounds and titration experiments. Further investigations of the reaction mechanism with a combination of experimental and DFT methods support the competing nature of acid-catalyzed and radical cationic ODHs, and indicate that both mechanisms operate with the current material. 相似文献