Complexes Metals
Mostrando 1-12 de 108 artigos, teses e dissertações.
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1. WSOC and Its Relationship with BC, Levoglucosan and Transition Metals in the PM2.5 of an Urban Area in the Amazon
Water-soluble organic carbon (WSOC) makes up a large mass fraction of the organic carbon in the aerosol and can influence important cloud processes in the atmosphere. The capacity of WSOC to form metallic complexes with transition metals is well known; however, its influence on the aerosol of urban areas in the Amazon region is not very well known. In this s
Journal of the Brazilian Chemical Society. Publicado em: 2022
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2. Determination of Copper and Cadmium in Petroleum Produced Formation Water by Electrothermal Atomic Absorption Spectrometry after Cloud Point Extraction
Cloud point extraction (CPE) in association with graphite furnace atomic absorption spectrometry (GF AAS) was proposed for preconcentration and quantification of trace amounts of copper and cadmium in samples of saline produced formation water from petroleum exploration. The procedure was based on the formation of hydrophobic complexes of the analytes with 1
J. Braz. Chem. Soc.. Publicado em: 2020-06
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3. SYNTHESIS, CHARACTERIZATION AND ANTIMICROBIAL ACTIVITY OF NEW Cu (II), Co (II) AND Sn (II) COMPLEXES WITH THE SODIUM HYDROTRIS(2-MERCAPTOTHIAZOLYL)BORATE LIGAND
The emergence of antibiotic resistance among microbial pathogens is a serious public health problem, resulting in a constant need of discovering new antibiotics. For this purpose, we synthetized and determined the antimicrobial activity of copper (Cu), cobalt (Co), and tin (Sn) complexes coordinated with scorpionate ligand in a tridentate mode against microo
Quím. Nova. Publicado em: 2020-05
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4. USO DA TEORIA DO FUNCIONAL DE DENSIDADE NA ANÁLISE DE SPIN CROSSOVER EM AULAS DE QUÍMICA INORGÂNICA
Spin crossover is a property found in some coordination compounds formed by the first series of transition metals with d4-d7 configuration. These complexes, when stimulated by an external factor (temperature, light, etc.), can be converted from their low spin states to high spin states, or vice versa. However, this issue is not addressed in the Inorganic Che
Quím. Nova. Publicado em: 2020-01
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5. ESPECIAÇÃO DINÂMICA DE METAIS TRAÇO EM AMBIENTE AQUÁTICO USANDO CRONOPOTENCIOMETRIA DE REDISSOLUÇÃO ANÓDICA
The contamination of natural environments by trace metals has several adverse effects on human health, which is mainly due to the high toxicity, persistence and reactivity of these species in the environment. To understand the bioavailability of trace metals, it is necessary to know the speciation in equilibrium and the dynamic behavior of the system. In thi
Quím. Nova. Publicado em: 2018-07
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6. New Organomineral Complex from Humic Substances Extracted from Poultry Wastes: Synthesis, Characterization and Controlled Release Study
The present study reports the synthesis and characterization of complexes formed among humic (HA) and fulvic acids (FA) derived from poultry wastes and ions Cu2+, Fe2+ and Zn2+. The release of such metals in a buffer solution simulating the soil solution was also evaluated. After complexation, the Fourier transform infrared (FTIR) spectra presented alteratio
J. Braz. Chem. Soc.. Publicado em: 2018-01
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7. Cellulose Oxidation and the Use of Carboxyl Cellulose Metal Complexes in Heterogeneous Catalytic Systems to Promote Suzuki-Miyaura Coupling and C-O Bond Formation Reaction
This work shows the modification of microcrystalline cellulose by the selective oxidation of primary hydroxyl groups to carboxylate groups by a 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated system and its application as a heterogeneous ligand by ionic exchange with catalytic metals ions such as palladium, nickel and copper. Afterwards is desc
J. Braz. Chem. Soc.. Publicado em: 2017-11
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8. Copper II - polar amino acid complexes: toxicity to bacteria and larvae of Aedes aegypti
ABSTRACT Control strategies using insecticides are sometimes ineffective due to the resistance of the insect vectors.In this scenario new products must be proposed for the control of insect vectors.The complexes L-aspartate Cu (II) and L-glutamate-Cu (II) complexes were synthesized and characterized by elemental analysis, visible ultraviolet, infrared spectr
An. Acad. Bras. Ciênc.. Publicado em: 20/07/2017
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9. Endophytic fungus Purpureocillium sp. A5 protect mangrove plant Kandelia candel under copper stress
Abstract Mangrove is an important ecosystem in the world. Mangrove ecosystems have a large capacity in retaining heavy metals, and now they are usually considered as sinks for heavy metals. However, the mechanism of why the soil of mangrove ecosystems can retain heavy metal is not certain. In this research, endophytic fungus Purpureocillium sp. A5 was isolat
Braz. J. Microbiol.. Publicado em: 2017-07
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10. Tilapia (Oreochromis niloticus) as a Biondicator of Copper and Cadmium Toxicity. A Bioavailability Approach
The acute toxicity of copper and cadmium in Oreochromis niloticus was evaluated through a 96 h static assay. Precipitation of Cu and co-precipitation of Cd in the presence of Cu were noted, being indicative of differences in nominal and actual concentrations of metals. Under these conditions, LC50-96h was determined as 3.53 mg L-1Cu, 20.1 mg L-1 Cd and 1.36
J. Braz. Chem. Soc.. Publicado em: 2017-01
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11. Effect of Metal Acetylacetonates on the Photooxidative Destruction of High Density Polyethylene
The process of photooxidative destruction of high density polyethylene films containing different organic complexes of polyvalent metals as pro-oxidant additives after UV- irradiation was studied. During exposure to UV- irradiation, the more significant changes in the mechanical and thermal properties were detected for the foils containing pro-oxidant additi
Mat. Res.. Publicado em: 14/07/2016
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12. Multivariate Optimization of a Simultaneous Cloud Point Extraction Procedure of Cd, Cu and Ni from Sediments Samples and Determination by ICP OES
A simultaneous preconcentration method for cadmium, copper and nickel in samples of sediments and determination by inductively coupled plasma optical emission spectrometry was developed. The method is based on the extraction of the metals as complexes formed with 2-(5-bromo-2-pyridylazo)-5-(diethylamino)-phenol (5-Br-PADAP) at cloud point of the nonionic sur
J. Braz. Chem. Soc.. Publicado em: 2016-04