Spectroscopic Characterization
Mostrando 13-24 de 213 artigos, teses e dissertações.
-
13. CONSTITUINTES QUÍMICOS E ATIVIDADE INSETICIDA DE Miconia ferruginata
Phytochemical investigation of the leaf extracts from Miconia ferruginata (Melastomataceae) led to the isolation and characterization of the flavonoids 5,6,7-trihydroxy-4'-methoxyflavone, 5-hydroxy-7,4'-dimethoxy-8-methylflavone and 5,7,4'-trihydroxy-6,8-dimetilflavone, triterpenes ursolic acid and oleanolic acid, in addition to the steroids β-sitosterol an
Quím. Nova. Publicado em: 2017-10
-
14. Spectroscopic Characterization of Charge Transfer Complexes of TCNE with Aromatic Amines - The First Step of Tricyanovinylation Reaction
The first step of electrophilic aromatic substitution reactions generally involves the formation of charge transfer complexes. Tetracyanoethylene (TCNE) in the presence of aromatic amines forms π-type complexes that subsequently lead to tricyanovinylation reaction. Although this kind of reaction was investigated in the past, the spectroscopic characterizati
J. Braz. Chem. Soc.. Publicado em: 2017-09
-
15. Thermoanalytical, Spectroscopic and DFT Studies of Heavy Trivalent Lanthanides and Yttrium(III) with Oxamate as Ligand
Solid-state LnL3∙nH2O complexes, where Ln stands for trivalent lanthanides (Tb to Lu) or yttrium(III) and L is oxamate (NH2COCO2-), have been synthesized. The characterization of the complexes was performed by using elemental analysis (EA), complexometric titration with EDTA, thermoanalytical techniques such as simultaneous thermogravimetry and differentia
Mat. Res.. Publicado em: 22/06/2017
-
16. Synthesis and Characterization of a New Unsymmetrical Potentially Pentadentate Schiff Base Ligand and Related Complexes with Manganese(II), Nickel(II), Copper(II), Zinc(II) and Cadmium(II)
New unsymmetric thioether Schiff base amine, 2-(2-aminoethylthio)-N-(thiophene-2-ylmethylene)aniline was prepared by reaction of 2-aminothiophenol with N-(2-bromoethyl)phthalimide and then by thiophene-2-carbaldehyde. Then, the phthalimide group converted to the amine by hydrazine hydrate. The new potentially pentadentate N3S2 donor unsymmetrical Schiff base
J. Braz. Chem. Soc.. Publicado em: 2017-05
-
17. Isolation and characterization of flavanols from Anthocephalus cadamba and evaluation of their antioxidant, antigenotoxic, cytotoxic and COX-2 inhibitory activities
ABSTRACT In search of lead molecules for use in disease prevention and as food additive from natural sources, two flavanols were isolated from leaves of Anthocephalus cadamba (Roxb.) Miq., Rubiaceae. Their structures were established as 6-hydroxycoumarin-(4"→8)-(-)-epicatechin and 6-hydroxycoumarin-(4"→8)-(-)-epicatechin-(4→6‴)-(-)-epicatechin on the
Rev. bras. farmacogn.. Publicado em: 2016-08
-
18. Preparation and Characterization of the Structural, Optical, Spectroscopic and Electrical Properties of Pr2O5 doped Borate Glass
Abstract We have successfully synthesized Pr2O5 doped borate glasses by conventional rapid melt quench method. The XRD pattern indicates the amorphous nature of Pr2O5 doped borate glass. An optical property of prepared borate glass was studied using the Photoluminescence spectrum. Determination and differentiation of the various vibrational modes were done u
Mat. Res.. Publicado em: 18/07/2016
-
19. Comparison of Gold CD-R Types as Electrochemical Device and as Platform for Biosensors
The construction of gold electrodes using 3 kinds of gold recordable compact discs (CDtrodes) and characterization by electrochemical and spectroscopic techniques are herein reported. Following a surface pretreatment in 0.5 mol L-1 sulfuric acid (H2SO4), the electrochemical experiments were performed in the presence of redox couple ferro/ferricyanide [Fe(CN)
J. Braz. Chem. Soc.. Publicado em: 2016-04
-
20. Characterization and evaluation of the cytotoxic potential of the essential oil of Chenopodium ambrosioides
Abstract The essential oil of Chenopodium ambrosioides L., Amaranthaceae, was obtained by steam distillation in a Clevenger apparatus and characterization was performed using chromatographic and spectroscopic assays (GC-FID, GC/MS, 1H NMR). Two major compounds were identified: p-cymene (42.32%) and ascaridole (49.77%). The ethanolic extract and hydrolate wer
Rev. bras. farmacogn.. Publicado em: 2016-02
-
21. Surface Modification and Spectroscopic Characterization of TiO2 Nanoparticles with 2-Aminoethyl Dihydrogen Phosphate
A common strategy for the surface modification of nano TiO2 and other metal oxide nanoparticles is based on anchor groups using chelating ligands that can carry additional functionalities. This would allow the exploration of further applications of these materials. In the present work, we report the modification of TiO2 nanoparticles
J. Braz. Chem. Soc.. Publicado em: 2015-08
-
22. Biological Activity Studies on Metal Complexes of Macrocyclic Schiff Base Ligand: Synthesis and Spectroscopic Characterization
In this study, we prepared the macrocyclic Schiff base ligand (L) derived from 1,4-dicarbonylphenyl- dihydrazide and pentane-2,4-dione (2:2) and its CoII, CuII and NiII complexes. The compounds were characterized by the analytical and spectroscopic methods like elemental analysis, molar conductance measurements, mass spect
J. Braz. Chem. Soc.. Publicado em: 2015-07
-
23. New aminoporphyrins bearing urea derivative substituents: synthesis, characterization, antibacterial and antifungal activity
This work studied the synthesis of 5,10,15-tris(4-aminophenyl)-20-(N,N-dialkyl/diaryl-N-phenylurea) porphyrins (P1-P4 with alkyl or aryl groups of Ph, iPr, Et and Me, respectively) and also the preparation of their manganese (III) and cobalt (II) complexes (MnP and CoP). The P1-P4 ligands were characterized by different spectroscopic techniques (1H NMR, FTIR
Braz. arch. biol. technol.. Publicado em: 2015-06
-
24. Adhesivos tipo poliuretano obtenidos a partir de aceite de ricino y almidón químicamente modificados
This study reports the preparation of polyurethane adhesives using polyols obtained from castor oil modified by a transesterification reaction with pentaerythritol and starch modified by glycosylation. The physical properties of the polyols such as hydroxyl value were determined and the infrared spectroscopic analysis of the polyols reported. The effect of v
Quím. Nova. Publicado em: 2013