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排序方式: 共有78条查询结果,搜索用时 312 毫秒
1.
Maria Luiza Zeraik Ivani Pauli Luiz A. Dutra Raquel S. Cruz Marilia Valli Luana C. Paracatu Carolina M. Q. G. de Faria Valdecir F. Ximenes Luis O. Regasini Adriano D. Andricopulo Vanderlan S. Bolzani 《Molecules (Basel, Switzerland)》2021,26(8)
Cyclooxygenase (COX) and lipoxygenase (LOX) are key targets for the development of new anti-inflammatory agents. LOX, which is involved in the biosynthesis of mediators in inflammation and allergic reactions, was selected for a biochemical screening campaign to identify LOX inhibitors by employing the main natural product library of Brazilian biodiversity. Two prenyl chalcones were identified as potent inhibitors of LOX-1 in the screening. The most active compound, (E)-2-O-farnesyl chalcone, decreased the rate of oxygen consumption to an extent similar to that of the positive control, nordihydroguaiaretic acid. Additionally, studies on the mechanism of the action indicated that (E)-2-O-farnesyl chalcone is a competitive LOX-1 inhibitor. Molecular modeling studies indicated the importance of the prenyl moieties for the binding of the inhibitors to the LOX binding site, which is related to their pharmacological properties. 相似文献
2.
Experimental and Theoretical Studies on Arene‐Bridged Metal–Metal‐Bonded Dimolybdenum Complexes
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Dr. Mario Carrasco Natalia Curado Dr. Eleuterio Álvarez Dr. Celia Maya Dr. Riccardo Peloso Prof. Dr. Manuel L. Poveda Dr. Amor Rodríguez Prof. Dr. Eliseo Ruiz Prof. Dr. Santiago Álvarez Prof. Dr. Ernesto Carmona 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(20):6092-6102
The bis(hydride) dimolybdenum complex, [Mo2(H)2{HC(N‐2,6‐iPr2C6H3)2}2(thf)2], 2 , which possesses a quadruply bonded Mo2II core, undergoes light‐induced (365 nm) reductive elimination of H2 and arene coordination in benzene and toluene solutions, with formation of the MoI2 complexes [Mo2{HC(N‐2,6‐iPr2C6H3)2}2(arene)], 3?C6H6 and 3?C6H5Me , respectively. The analogous C6H5OMe, p‐C6H4Me2, C6H5F, and p‐C6H4F2 derivatives have also been prepared by thermal or photochemical methods, which nevertheless employ different Mo2 complex precursors. X‐ray crystallography and solution NMR studies demonstrate that the molecule of the arene bridges the molybdenum atoms of the MoI2 core, coordinating to each in an η2 fashion. In solution, the arene rotates fast on the NMR timescale around the Mo2‐arene axis. For the substituted aromatic hydrocarbons, the NMR data are consistent with the existence of a major rotamer in which the metal atoms are coordinated to the more electron‐rich C?C bonds. 相似文献
3.
Evaldo M. F. Curado Sofiane Faci Jean-Pierre Gazeau Diego Noguera 《Entropy (Basel, Switzerland)》2022,24(2)
In quantum information processing, using a receiver device to differentiate between two non-orthogonal states leads to a quantum error probability. The minimum possible error is known as the Helstrom bound. In this work, we study the conditions for state discrimination using an alphabet of squeezed coherent states and compare them with conditions using the Glauber-Sudarshan, i.e., standard, coherent states. 相似文献
4.
5.
Sauaia MG de Lima RG Tedesco AC da Silva RS 《Journal of the American Chemical Society》2003,125(48):14718-14719
The binuclear complex [RuII(NH3)5(pz)RuII(bpy)2(NO)](PF6)5 was prepared and characterized by elemental analysis, UV-vis, and IR spectroscopy. The complex UV-vis spectrum has presented bands at 242, 286, and 530 nm in acetate buffer solution at pH 4.5. The photochemical study by laser flash-photolysis at 532 nm showed the NO release account from the NO measured by a NO sensor. The quantum yield for NO release (0.025 +/- 0.004 mol einsten-1) was determined with a laser flash-photolysis apparatus (Continuum Q-switched Nd:YAG laser). The major irradiation product of the [RuII(NH3)5(pz)RuII(bpy)2(NO)]5+ complex besides nitric oxide is [RuIII(NH3)5(pz)RuII(bpy)2(H2O)]5+. 相似文献
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7.
Ronaldo Giro Liliana Y. A. Davila Angelita M. Machado Marilia J. Caldas Leni Akcelrud 《International journal of quantum chemistry》2010,110(4):885-892
We focus this work on the theoretical investigation of the block‐copolymer poly[oxyoctyleneoxy‐(2,6‐dimethoxy‐1,4phenylene‐1,2‐ethinylene‐phenanthrene‐2,4diyl) named as LaPPS19, recently proposed for optoelectronic applications. We used for that a variety of methods, from molecular mechanics to quantum semiempirical techniques (AM1, ZINDO/S‐CIS). Our results show that as expected isolated LaPPS19 chains present relevant electron localization over the phenanthrene group. We found, however, that LaPPS19 could assemble in a π‐stacked form, leading to impressive interchain interaction; the stacking induces electronic delocalization between neighbor chains and introduces new states below the phenanthrene‐related absorption; these results allowed us to associate the red‐shift of the absorption edge, seen in the experimental results, to spontaneous π‐stack aggregation of the chains. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 相似文献
8.
Torrent-Sucarrat M Ruiz-Lopez MF Martins-Costa M Francisco JS Anglada JM 《Chemistry (Weinheim an der Bergstrasse, Germany)》2011,17(18):5076-5085
We have investigated the HO(2) adsorption and acid dissociation process on the surface of (H(2)O)(20) and (H(2)O)(21) clusters by using quantum-chemistry calculations. Our results show that the radical forms a stable hydrogen-bond complex on the cluster. The HO(2) acid dissociation is more favorable in the case of the (H(2)O)(21) cluster, for which the inner water molecule plays a crucial role. In fact, acid dissociation of HO(2) is found to occur in two steps. The first step involves H(2) O autoionization in the cluster, and the second one involves the proton transfer from the HO(2) radical to the hydroxide anion. The presence of the HO(2) radicals on the surface of the cluster facilitates water autoionization in the cluster. 相似文献
9.
We discuss the role of generalized Heisenberg algebras (GHA) in obtaining an algebraic method to describe physical systems. The method consists in finding the GHA associated to a physical system and the relations between its generators and the physical observables. We choose as an example the infinite square-well potential for which we discuss the representations of the corresponding GHA. We suggest a way of constructing a physical realization of the generators of some GHA and apply it to the square-well potential. An expression for the position operator x in terms of the generators of the algebra is given and we compute its matrix elements. 相似文献
10.
Hassan K. Khartabil Marilia T. C. Martins-Costa Philippe C. Gros Yves Fort Manuel F. Ruiz-López 《Theoretical chemistry accounts》2008,121(5-6):321-326
Molecular dynamics simulations of organolithium aggregates in solution are reported for the first time. We use a combined quantum/classical force field (the so-called QM/MM approach) and study ethyl-lithium aggregates in dimethyl ether (DME) solvent. The solutes are described at the Density Functional Theory level while solvent molecules are described using molecular mechanics. NVT Molecular Dynamics simulations at 200 K are carried out in the Born–Oppenheimer approximation. After equilibration, the production phase was run for 80 ps (monomer), 40 ps (dimer) and 26 ps (tetramer). The analysis of the results focuses on Li coordination as a function of aggregate size and we show that the total Li coordination number is always 4. No decoordination has been observed along the simulations. Fluctuations of the structures are predicted to be large in some cases and possible implications on reactivity are discussed. 相似文献