Intramolecular Hydrogen Bond
Mostrando 1-12 de 43 artigos, teses e dissertações.
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1. Crystal Structure and Hirshfeld Surface Analysis of 1,4-Pentadien-3-one, (1E,4E)-1,5-diphenyl-2-(2,4-dinitrophenyl)hydrazone
The compound 1,4-pentadien-3-one,(1E,4E)-1,5-diphenyl-2-(2,4-dinitrophenyl)hydrazone presents the molecular formula C23H18N4O4 and was prepared in an undergraduate laboratory. The hydrazone was synthesized from the condensation between dibenzalacetone and 2,4-dinitrophenylhydrazine (DNPH) and crystallized employing water/acetone liquid-liquid diffusion. The
J. Braz. Chem. Soc.. Publicado em: 2021-02
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2. Multiple Dynamics of Hydrazone Based Compounds
Hydrazone derivatives of 2-quinolinecarboxaldehyde and 6-bromo-2-pyridinecarboxaldehyde were synthesized by sequence reactions with hydrazine derivatives. These compounds exhibited E/Z isomerization upon irradiation using a mercury lamp (250 W). The configurational changes were monitored by 1H nuclear magnetic resonance (NMR), UV-Vis and fluorescence spectro
J. Braz. Chem. Soc.. Publicado em: 2015-06
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3. Molecular Electronic Topology and Fragmentation Onset via Charge Partition Methods and Nuclear Fukui Functions: 1,1-Diamino-2,2-dinitroethylene
We investigated theoretically the ground state electronic structure and the onset of molecular fragmentation of 1,1-diamino-2,2-dinitroethylene (FOX-7) using density functional theory. The molecular charge density was analyzed via two partition methods: the distributed multipole analysis (DMA) and the deformed atoms in molecules (DAM). In this framework, the
J. Braz. Chem. Soc.. Publicado em: 2015-05
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4. Modulating the electronic structure of amino acids: interaction of model lewis acids with anthranilic acid
On the basis of theoretical B3LYP calculations, Yáñez and co-workers (J. Chem. Theory Comput. 2012, 8, 2293) illustrated that beryllium ions are capable of significantly modulating (changing) the electronic structures of imidazole. In this computational organic chemistry study, the interaction of this β-amino acid and five model Lewis acids (BeF1+, Be2+,
Quím. Nova. Publicado em: 2014
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5. Synthesis, characterization and computational studies of (E)-2-{[(2-aminopyridin-3-yl)imino]-methyl}-4,6-di-tert-butylphenol
(E)-2-{[(2-Aminopyridin-3-yl)imino]-methyl}-4,6-di-tert-butyl-phenol ( 3: ), a ligand containing an intramolecular hydrogen bond, was prepared according to a previous literature report, with modifications, and was characterized by UV-vis, FTIR, ¹H-NMR, 13C-NMR, HHCOSY, TOCSY and cyclic voltammetry. Computational analyses at the level of DFT and TD-DFT were
Quím. Nova. Publicado em: 2014
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6. Electron-beam processed corn starch: evaluation of physicochemical and structural properties and technical-economic aspects of the processing
The properties of starch can be modified by a variety of methods in order to meet desirable technological needs. Electron beam irradiation is able to induce changes in starch properties. The paper deals with investigation of physicochemical and structural modifications of corn starch processed by electron beam up to 50 kGy and evaluation of the technical-eco
Braz. J. Chem. Eng.. Publicado em: 2013-12
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7. MOLECULAR CHARACTERIZATION OF BIOPOLIMERS IN SOLUTION BY COMPUTATIONAL SIMULATION / Caracterização molecular de biopolímeros em solução utilizando simulação computacional
Computer simulation methods were used to characterize the structure and molecular properties of natural and synthetic biopolymers in aqueous solution. The polysaccharides chitin and chitosan, and aliphatic polypeptides were studied. The interest on the chitin and chitosan biopolymers is because of their biodegradability, biocompatibility and potential use as
Publicado em: 2009
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8. SYNTHESIS AND CHARACTERIZATION OF OXIMES LIGANDS AND THIOSEMICARBAZONES AND THEIR COMPLEXES / SÍNTESE E CARACTERIZAÇÃO DE LIGANTES OXIMAS E TIOSSEMICARBAZONAS E SEUS COMPLEXOS
This research shows the synthesis and characterization of five ligands and four complexes derived from oximes and thiosemicarbazones. It analyses the crystalline/molecular structures determined by X-ray difraction in monocrystals: the ligand 4- phenylthiosemicarbazone-isatin (Ligand 5), the complexes pyridine-salicylaldehyde-4- phenylthiosemicarbazone of Ni(
Publicado em: 2009
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9. Synthesis and Structural Analysis of new Coordination Polymer and molecular compounds of Phosphinatos Metals. / SÍNTESE E ANÁLISE ESTRUTURAL DE NOVOS POLÍMEROS DE COORDENAÇÃO E COMPOSTOS MOLECULARES DE FOSFINATOS METÁLICOS
In this work, the structures of coordination polymers and molecular compounds Cu(II), Hg(II), Pb(II) and Cd(II) with phenylphosphinate or diphenylphosphinate ligands were determined and are discussed. The reaction of phenylphosphinic or diphenylphosphinic acid with copper(II) acetate hydrate produces respectively aquaphenylphosphinate copper(II) or quadiphen
Publicado em: 2007
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10. INVESTIGATION OF THE STRUCTURAL EFFECTS OF LIGANDS 1,3-DIARIL TRIAZENIDOS SYMMETRICAL ORTO-SUBSTITUTEDS IN MERCURYS COMPLEXES (II) / INVESTIGAÇÃO DOS EFEITOS ESTRUTURAIS DE LIGANTES 1,3- DIARILTRIAZENIDOS SIMÉTRICOS ORTO-SUBSTITUÍDOS EM COMPLEXOS DE MERCÚRIO (II)
This work was accomplished with the interest in the synthesis of ortosubstituted ligands, with special prominence to the moiety __CF3, __Br and __NO2 and later the complexação with Hg(II). The first obtained result was the crystalline structure of the ligand (1), it crystallizes in the system crystalline monoclínico, space group Cc, with the given followi
Publicado em: 2007
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11. "Intramolecular charge and hydrogen bon transfer in 9-aminoacridine derivatives" / "Transferência de carga e ligação de hidrogênio intramolecular em derivados de 9-aminoacridina"
Neste trabalho, o corante 9-aminoacridina foi derivatizado com compostos vinílicos que possuem grupos retiradores de elétrons. A incorporação destes leva à mudanças nas propriedades fotofísicas dos derivados, tais como deslocamentos para regiões de menor energia nos espectros de absorção e emissão, sugerindo a presença de transferência de carga
Publicado em: 2006
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12. Método de Monte Carlo utilizando cálculos de energia total AB initio / Monte Carlo method using AB initio total energy calculation
Computer simulations are essential tools to the research of physical systems at finite temperatures. Monte Carlo (MC) and Molecular Dynamics (MD) methods are the major techniques used for this purpose, and empirical potentials are traditionally employed in these simulations. These potentials, however, are built to describe with precision the system near some
Publicado em: 2006