Página 1 dos resultados de 176 itens digitais encontrados em 0.015 segundos

Hydrocarbon oxidation catalyzed by iron and manganese porphyrins anchored on aminofunctionalized supports

FARIA, André L.; MAC LEOD, Tatiana O. C.; BARROS, Valéria P.; ASSIS, Marilda D.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
27.10974%
The second-generation metalloporphyrins (MePs) [5,10,15,20-tetrakis(pentafluorophenyl)porphyrin iron(III)] chloride, FeP, and [5,10,15,20-tetrakis(pentafluorophenyl)porphyrin manganese(III)] chloride, MnP, were covalently attached to aminofunctionalized supports, with a view to preparing selective solid catalysts for the oxidation of organic compounds. Montmorillonite K10 functionalized with 3-aminopropyltriethoxysilane (Mont1) or modified with 3-chloropropyltriethoxysilane followed by reaction with 1,6-diaminohexane (Mont2), and silica gel functionalized with 3-aminopropyltriethoxysilane (Sil1) or modified with 3-chloropropyltriethoxysilane followed by reaction with 1,6-diaminohexane (Sil2) were synthesized and characterized by UV-Vis and IR spectroscopies, EPR, TGA, and X-ray diffractometry. The catalytic activities of the MePs immobilized on these supports were investigated for the oxidation of (Z)-cyclooctene, cyclohexane and styrene by PhIO or H2O2. The studied systems were efficient catalysts for the oxidation of all substrates, especially when PhIO was the oxidant. There was no MeP leaching from the supports, indicating that covalent binding is a very efficient method for catalyst immobilization. The immobilized FePs were more efficient catalysts than the corresponding MnPs...

Primidone oxidation catalyzed by metalloporphyrins and Jacobsen catalyst

LEOD, T. C. O. Mac; FARIA, A. L.; BARROS, V. P.; QUEIROZ, M. E. C.; ASSIS, M. D.
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
27.10974%
Primidone (PRM) oxidation by various oxidants such as iodosylbenzene (PhIO), tert-butyl hydroperoxide 70wt.% (t-BOOH), 3-chloroperoxybenzoic acid (m-CPBA) and hydrogen peroxide 30wt.%, mediated by either a salen complex or metalloporphyrins, was investigated. The catalytic systems led to phenylethyl-malondiamide (PEMA) and phenobarbital (FEND), the same metabolites obtained in vivo with P450 enzymes, although three other products were also detected. Product formation was highly dependent on the oxidant, co-catalyst (imidazole), pH and dioxygen. These biomimetic chemical models have potential application in the synthesis of drug metabolites. which should provide samples for pharmacological tests. They can also be employed in studies that pursue the elucidation of in vivo drug metabolism. (C) 2008 Elsevier B.V. All rights reserved.; FAPESP; CAPES; CNPq

Estudos catalíticos da oxigenação de hidrocarbonetos utilizando metaloporfirinas fluorossubstituídas como catalisadores em meio homogêneo e heterogêneo; Catalytic studies on hidrocarbon oxidation using fluorosubstituted metalloporphyrins as catalysts in homogeneous and heterogeneous medium

Soares, Ana Paula Masson e
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 02/09/2004 PT
Relevância na Pesquisa
37.596604%
Manganês(III)porfirinas têm sido relatadas como eficientes catalisadores em reações de oxigenação de hidrocarbonetos por vários doadores de oxigênio. Numa primeira etapa, foram realizadas a síntese e caracterização das porfirinas base-livre, posterior introdução de grupo sulfonato na H2(MPTFPP), a fim de que esta pudesse ser utilizada em reações em meio heterogêneo, e inserção de metal nas porfirinas base-livre, obtendo-se os catalisadores cis-[Mn(BFPBPP)]Cl, trans-[Mn(BFPBPP)]Cl, [Mn(MSO3TFPP)]Cl e [Mn(TSO3PP)]Cl. Realizou-se a funcionalização da sílica gel contendo grupos trimetilamônio, que permitia sua ligação com metaloporfirinas contendo cargas negativas periféricas, com grupos imidazol, que permitem ligação com a metaloporfirina via ligação coordenativa, favorecendo o aumento da atividade catalítica destes sistemas. Os catalisadores [Mn(BFPBPP)]Cl, trans-[Mn(BFPBPP)]Cl, [Mn(MSO3TFPP)]Cl foram utilizados na epoxidação do (Z)-cicloocteno e na oxidação do cicloexano por PhIO em meio homogêneo. A Mn(III)porfirina aniônica apresentou rendimentos comparáveis a sistemas clássicos, acompanhados de uma melhor seletividade. Tais resultados, acompanhados da vantagem de que este sistema poderia ser utilizado em meio heterogêneo...

Metaloporfirinas como modelos biomiméticos do citocromo P450 na oxidação de pesticidas"; Metalloporhyrins as Biomimetical MOdels of Cytochrome P450 in the Oxidation of Pesticides

Gotardo, Maria Carolina Alves de Freitas
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 29/08/2006 PT
Relevância na Pesquisa
27.881597%
Neste trabalho foi investigado o potencial de modelos metaloporfirínicos em mimetizar a ação do citocromo P450 na oxidação de um herbicida, a atrazina. Foram utilizadas as metaloporfirinas comerciais de segunda geração solúveis em solvente orgânico, cloreto de 5,10,15,20-tetrakis(2,6-diclorofenil)porfirina metal(III) [M(TDCPP)Cl] e cloreto de 5,10,15,20-tetrakis(pentafluorofenil) porfirina metal(III) [M(TFPP)Cl] (metal = ferro e manganês), tanto em solução homogênea como suportadas em montmorilonita K-10 aminofuncionalizadas; e metaloporfirinas solúveis em água, como a cloreto de 5,10,15,20-tetrakis-(N-metil-4-piridil) porfirina ferro(III), [Fe(TMPy)Cl], e cloreto de [5,10,15,20-tetra(4-carboxifenil)porfirina] ferro(III), [Fe(TCPP)Cl]. Os oxidantes testados foram iodosilbenzeno, ácido metacloroperbenzóico e peróxido de hidrogênio em água, metanol e acetonitrila. Os produtos de oxidação da atrazina foram identificados por cromatografia líquida de alta eficiência (CLAE). Os resultados mostraram que as metaloporfirinas foram capazes de oxidar a atrazina, um herbicida com características de persistência no meio ambiente, e mimetizar a ação da enzima in vivo e in vitro com formação de dois metabólitos: DEA e DIA...

Metaloporfirinas e compostos salen como modelos biomiméticos do citocromo P450 no metabolismo de fármacos anticonvulsivante e antidepressivo; Metalloporphyrins and salen complexes as a P450 biomimetic model for the metabolism of antiepileptic and antidepressant drugs

Mac Leod, Tatiana Cristina de Oliveira
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 01/07/2008 PT
Relevância na Pesquisa
37.596604%
Neste trabalho foram estudadas a atividade catalítica de metaloporfirinas e complexos salen (catalisador de Jacobsen), em solução e imobilizados em diferentes suportes, na oxidação de hidrocarbonetos e fármacos anticonvulsivantes (carbamazepina e primidona) e antidepressivo (fluoxetina), utilizando os seguintes doadores de oxigênio: peróxido de hidrogênio, terc-butil hidroperóxido (t-BOOH), ácido m-cloroperbenzóico (m-CPBA) e iodosilbenzeno (PhIO). Os catalisadores contendo o complexo salen imobilizado em alumina, membranas de quitosana e membranas polidimetilssiloxano/acetato de polivinila (PDMS/PVA), foram preparados e caracterizados por espectroscopia UV-Vis, análise termogravimétrica, calorimetria exploratória diferencial, análise térmica diferencial, infravermelho, microscopia eletrônica de varredura, raios-X e área superficial. Foi investigada a atividade destes materiais inicialmente na catálise oxidativa de hidrocarbonetos (cicloocteno, estireno e cicloexano). Estes sistemas heterogêneos se mostraram bastante eficientes para oxidação destes substratos, com rendimentos de até 79 % de ciclooctenóxido e elevada seletividade para formação de epóxido ou cetona, quando se utilizam os substratos alcenos ou cicloexano...

Novel synthetic methodology for metalloporphyrins in ionic liquid

Singh,Ram; Geetanjali,
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2005 EN
Relevância na Pesquisa
37.411133%
5,10,15,20-Tetraarylporphyrins undergo metalation with metal salts in the presence of reusable 1-hexyl-3-methylimidazolium bromide ([hmim][Br]) as solvent at room temperature to afford the corresponding metalloporphyrins in 80-98% yields.

Binding Specificity of the Porphyromonas gingivalis Heme and Hemoglobin Receptor HmuR, Gingipain K, and Gingipain R1 for Heme, Porphyrins, and Metalloporphyrins

Olczak, Teresa; Dixon, Dabney White; Genco, Caroline Attardo
Fonte: American Society for Microbiology Publicador: American Society for Microbiology
Tipo: Artigo de Revista Científica
Publicado em /10/2001 EN
Relevância na Pesquisa
27.596604%
Previous genetic and biochemical studies have confirmed that hemoglobin and hemin utilization in Porphyromonas gingivalis is mediated by the outer membrane hemoglobin and heme receptor HmuR, as well as gingipain K (Kgp), a lysine-specific cysteine protease, and gingipain R1 (HRgpA), one of two arginine-specific cysteine proteases. In this study we report on the binding specificity of the recombinant P. gingivalis HmuR protein and native gingipains for hemoglobin, hemin, various porphyrins, and metalloporphyrins as assessed by spectrophotometric assays, by affinity chromatography, and by enzyme-linked immunosorbent assay. Protoporphyrin, mesoporphyrin, deuteroporphyrin, hematoporphyrin, and some of their iron, copper, and zinc derivatives were examined to evaluate the role of both the central metal ion and the peripheral substituents on binding to recombinant HmuR and soluble gingipains. Scatchard analysis of hemin binding to Escherichia coli cells expressing recombinant membrane-associated six-His-tagged HmuR yielded a linear plot with a binding affinity of 2.4 × 10−5 M. Recombinant E. coli cells bound the iron, copper, and zinc derivatives of protoporphyrin IX (PPIX) with similar affinities, and approximately four times more tightly than PPIX itself...

Differential effects of metalloporphyrins on messenger RNA levels of delta-aminolevulinate synthase and heme oxygenase. Studies in cultured chick embryo liver cells.

Cable, E E; Pepe, J A; Karamitsios, N C; Lambrecht, R W; Bonkovsky, H L
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /08/1994 EN
Relevância na Pesquisa
27.411133%
The acute porphyrias in relapse are commonly treated with intravenous heme infusion to decrease the activity of delta-aminolevulinic acid synthase, normally the rate-controlling enzyme in heme biosynthesis. The biochemical effects of heme treatment are short-lived, probably due in part to heme-mediated induction of heme oxygenase, the rate-controlling enzyme for heme degradation. In this work, selected nonheme metalloporphyrins were screened for their ability to reduce delta-aminolevulinic acid synthase mRNA and induce heme oxygenase mRNA in chick embryo liver cell cultures. Of the metalloporphyrins tested, only zinc-mesoporphyrin reduced delta-aminolevulinic acid synthase mRNA without increasing heme oxygenase mRNA. The combination of zinc-mesoporphyrin and heme, at nanomolar concentrations, decreased delta-aminolevulinic acid synthase mRNA in a dose-dependent manner. The combination of zinc-mesoporphyrin (50 nM) and heme (200 nM) decreased the half-life of the mRNA for delta-aminolevulinic acid synthase from 5.2 to 2.5 h, while a similar decrease was produced by heme (10 microM) alone (2.2 h). The ability of zinc-mesoporphyrin to supplement the reduction of delta-aminolevulinic acid synthase mRNA by heme, in a process similar to that observed with heme alone...

Energy-structure correlation in metalloporphyrins and the control of oxygen binding by hemoglobin.

Warshel, A
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /05/1977 EN
Relevância na Pesquisa
27.411133%
The contribution of the porphyrin skeleton to the potential energy surface metalloporphyrins is calculated by the semiempirical method of quantum mechanical extension of the consistent force field to eta electron molecules. This calculation makes it possible to correlate the observed structure of metalloporphyrins with the strain energy of the porphyrin skeleton. It is found that the out-of-plane metal displacement in pentacoordinate heme systems is due to both the restricted size of the porphyrin hole and the "1-3" steric interaction between the axial ligand and the heme nitrogens. The main components of the active site of hemoglobin are simulated by a histidine-heme-oxygen system. The energy surface of this system provides a quantitative explanation for the control of ligand binding by hemoglobin. It is shown that the heme acts as a diaphragm, designed to provide simultaneous binding to the histidine and the sixth ligand under the steric requirements of the 1-3 interactions. The dependence of the hemoglobin potential surface on the distance between the proximal histidine and the heme plane is evaluated for the R and T states, using the calculated heme potential and the observed energy of heme-heme interaction.

Chloroplast Biogenesis: XXIV. Intrachloroplastic Localization of the Biosynthesis and Accumulation of Protoporphyrin IX, Magnesium-Protoporphyrin Monoester, and Longer Wavelength Metalloporphyrins during Greening 1

Smith, Barry B.; Rebeiz, Constantin A.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /02/1979 EN
Relevância na Pesquisa
27.812988%
The intraplastidic localization of the endogenous metabolic pools from protoporphyrin to protochlorophyll was determined in Cucumis sativus. The endogenous protoporphyrin, Mg-protoporphyrin monoester + longer wavelength metalloporphyrins, protochlorophyllide and protochlorophyllide ester were membrane-bound. Protoporphyrin was synthesized in the stroma and subsequently became associated with the membranes. The membrane-associated protoporphyrin was then converted into Mg-protoporphyrin monoester + longer wavelength metalloporphyrins by membrane-bound enzymes. Although lysed plastids were capable of converting exogenous δ-aminolevulinic acid to protochlorophyllide, the net synthesis of protochlorophyllide from exogenous δ-aminolevulinic acid was lost upon segregating the lysed plastids into stromal and membrane fractions and then recombining the stromal and membrane fraction prior to incubation. The segregated membrane fraction was still capable of converting protoporphyrin into Mg-protoporphyrin monoester + longer wavelength metalloporphyrins in the presence or absence of the stromal fraction. These results indicated that although the reactions from protoporphyrin to Mg-protoporphyrin monoester and longer wavelength metalloporphyrins could survive a considerable degree of plastid disruption...

Immunochemistry of sperm-whale myoglobins prepared with various modified porphyrins and metalloporphyrins

Atassi, M. Z.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /04/1967 EN
Relevância na Pesquisa
27.411133%
1. The preparation and characterization of manganese, iron, cobalt, nickel, copper and zinc metalloporphyrins is described. Ferrihaem was also esterified with pyrid-4-ylpropanol and the derivative characterized as the diester. 2. Complexes of these various porphyrins, as well as protoporphyrin IX, with apomyoglobin were formed and the resulting artificial myoglobins characterized. 3. Very little complex-formation was obtained with nickel, cobalt and manganese metalloporphyrins and apomyoglobin. 4. Myoglobin prepared with copper metalloporphyrin was immunochemically identical with native ferrimyoglobin. All the other artificial myoglobins were less reactive to varying degrees. 5. The changes in antigenic reactivities were attributed to conformational reorganization caused by the different co-ordination tendencies of the various metals or by the modification of the side chains of the haem.

Metalloporphyrins – An Update

Schulz, Stephanie; Wong, Ronald J.; Vreman, Hendrik J.; Stevenson, David K.
Fonte: Frontiers Research Foundation Publicador: Frontiers Research Foundation
Tipo: Artigo de Revista Científica
Publicado em 26/04/2012 EN
Relevância na Pesquisa
27.411133%
Metalloporphyrins are structural analogs of heme and their potential use in the management of neonatal hyperbilirubinemia has been the subject of considerable research for more than three decades. The pharmacological basis for using this class of compounds to control bilirubin levels is the targeted blockade of bilirubin production through the competitive inhibition of heme oxygenase (HO), the rate-limiting enzyme in the bilirubin production pathway. Ongoing research continues in the pursuit of identifying ideal metalloporphyrins, which are safe and effective, by defining therapeutic windows and targeted interventions for the treatment of excessive neonatal hyperbilirubinemia.

Inhibitory effect of metalloporphyrins in conjunction with cholesterol on hepatic phospholipase A2 activityin vivo in rats

Chandra, Ramesh; Tiwari, Manisha; Aneja, Ritu; Dass, Sujata K.; Sharma, Archana
Fonte: Springer India Publicador: Springer India
Tipo: Artigo de Revista Científica
Publicado em /07/2000 EN
Relevância na Pesquisa
27.411133%
We investigated the effect of cholesterol and the metalloporphyrins cobalt mesoporphyrin (CoMP) and chromium protoporphyrin (CrPP) on phospholipase A2 (PLA2) activity and the consequent hepatic mitochondrial stability as well as on lipid concentrations. Our studies revealed that on administration of cholesterol, CrPP, CoMP as well as simultaneous adminstration of cholesterol and CrPP, there was an inhibition of PLA2 activity. These moieties may therefore, be agents for preventing destabilisation of the mitochondrial membrane and the consequent pathological conditions which may arise due to membrane lysis. Our results revealed that cholesterol administration increased phospholipid concentration, albeit by modest amounts. Although the independent administration of metalloporphyrins led only to minor elevations in phospholipid concentration, the simultaneous administration of cholesterol and CrPP generated a steep elevation in the concentration of total phospholipid. Since cholesterol inhibits PLA2 activity it has the potential of being therapeutic agent for preventing the pathological conditions which may arise due to membrane lysis.

Metalloporphyrins—Applications and clinical significance

Chandra, Ramesh; Tiwari, Manisha; Kaur, Parvinder; Sharma, Meenakshi; Jain, Ritu; Dass, Sujata
Fonte: Springer India Publicador: Springer India
Tipo: Artigo de Revista Científica
Publicado em /08/2000 EN
Relevância na Pesquisa
37.411133%
The fascinating structures of naturally occurring porphyrins and metalloporphyrins have been perfected by nature to give functional dyes par excellence. The important roles these tetrapyrrolic macrocycles play in vital biological processes, in particular photosynthesis (chlorophyll), oxygen transport (hemoglobin), oxygen activation (cytochrome), have led to their characterization as ‘pigments of life’. Because porphyrins possess extended π-electron systems and exhibit stability, they are finding use, to an increasing extent, in advanced materials, as components in organic metals, molecular wires, and other devices. In medicine, porphyrins are experiencing a renaissance due to the advent of photodynamic therapy of great promise in the treatment of cancer and dermatological diseases. The interdisciplinary interest porphyrins thus generate has provided the impetus to develop Novel-porphyrin like molecules anticipated to exhibit special properties, by structural variation of the tetrapyrrolic macrocycle, while maintaining a (4n+2)π main conjugation pathway.

Protective Effect of Metalloporphyrins against Cisplatin-Induced Kidney Injury in Mice

Pan, Hao; Shen, Kezhen; Wang, Xueping; Meng, Hongzhou; Wang, Chaojun; Jin, Baiye
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 14/01/2014 EN
Relevância na Pesquisa
27.596604%
Oxidative and nitrative stress is a well-known phenomenon in cisplatin-induced nephrotoxicity. The purpose of this work is to study the role of two metalloporphyrins (FeTMPyP and MnTBAP), water soluble complexes, in cisplatin-induced renal damage and their ability to scavenge peroxynitrite. In cisplatin-induced nephropathy study in mice, renal nitrative stress was evident by the increase in protein nitration. Cisplatin-induced nephrotoxicity was also evident by the histological damage from the loss of the proximal tubular brush border, blebbing of apical membranes, tubular epithelial cell detachment from the basement membrane, or intra-luminal aggregation of cells and proteins and by the increase in blood urea nitrogen and serum creatinine. Cisplatin-induced apoptosis and cell death as shown by Caspase 3 assessments, TUNEL staining and DNA fragmentation Cisplatin-induced nitrative stress, apoptosis and nephrotoxicity were attenuated by both metalloporphyrins. Heme oxygenase (HO-1) also plays a critical role in metalloporphyrin-mediated protection of cisplatin-induced nephrotoxicity. It is evident that nitrative stress plays a critical role in cisplatin-induced nephrotoxicity in mice. Our data suggest that peroxynitrite is involved...

Inhibition of Mitochondrial Hydrogen Peroxide Production by Lipophilic Metalloporphyrins

Castello, Pablo R.; Drechsel, Derek A.; Day, Brian J.; Patel, Manisha
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
27.722246%
Many studies have established a role for oxidative stress and mitochondrial dysfunction as an important mechanism in the pathogenesis of neuronal disorders. Metalloporphyrins are a class of catalytic antioxidants that are capable of detoxifying a wide range of reactive oxygen species. The AEOL112 series of glyoxylate metalloporphyrins were designed with increased lipid solubility for better oral bioavailability and penetration of the blood-brain barrier. The goal of this study was to develop an in vitro assay using rat brain mitochondria to reliably detect endogenously released hydrogen peroxide (H2O2) and identify glyoxylate metalloporphyrins based on rank order of potency for removal of physiologically relevant H2O2. A polarographic method was established for the sensitive, accurate, and reproducible detection of low levels of H2O2. The assay identified several potent glyoxylate metalloporphyrins with H2O2 scavenging potencies (IC50) in the nanomolar range. These results provide a simplified in vitro model system to detect physiologically generated mitochondrial H2O2 as a screening tool to predict the biological efficacy of potential therapeutic entities.

Synthesis and characterization of new chromium and aluminum metalloporphyrins in route to water-soluble buckminsterfullerene radical anion salts

DeGroff Puhek, Cynthia Lucil
Fonte: Universidade Rice Publicador: Universidade Rice
ENG
Relevância na Pesquisa
27.411133%
Five new metalloporphyrins, $ m lbrack Alsp{III} (TPPCM)Cl brack,$ $ m lbrack Alsp{III} (TPPCN)Cl brack,$ $ m lbrack Alsp{III} (TPPC)Cl brack,$ $ m lbrack Crsp{III} (TPPCM)Cl brack,$ and $ m lbrack Crsp{III} (TPPCN)Cl brack,$ have been synthesized and characterized as a first step toward the bulk synthesis of water-soluble C$sb{60}sp{.-}$ salts. According to a literature report, Cr$ m sp{II}$(TPP) and (Al$ m sp{III}$(TPP)$sp{.-} brack$ (TPP$sp{2{-}}$ = tetraphenylporphyrinato) reduce C$sb{60}$ to C$sb{60}sp{.-}$ under proper solvent conditions to form an insoluble $ m lbrack Crsp{III}(TPP) bracksp+(Csb{60}sp{.-})$ or (Al$ m sp{III}$(TPP)$ bracksp+$(C$sb{60}sp{.-})$ salt. Here it is proposed to derivatize these Cr$ m sp{II}$ and Al$ m sp{III}$ tetraphenylporphyrins with substituents on the phenyl rings to produce water-soluble $ m lbrack Crsp{III} (TPPR) bracksp+(Csb{60}sp{.-})$ and $ m lbrack Alsp{III} (TPPR) bracksp+(Csb{60}sp{.-})$ salts. Initial electrochemical data for precursor $ m lbrack Alsp{III} (TPPCM)Cl brack,$ $ m lbrack Alsp{III} (TPPCN)Cl brack,$ $ m lbrack Alsp{III} (TPPC)Cl brack,$ $ m lbrack Crsp{III} (TPPCM)Cl brack,$ and $ m lbrack Crsp{III} (TPPCN)Cl brack$ compounds suggest that adding water-solubilizing substituents does not interfere with the electron transfer between the reduced Al$ m sp{III}$ and C$ m sp{II}$ metalloporphyrins and C$sb{60}.$ Hence...

Análises de oxidação de triazínas com 'H IND.2 O IND.2' e catalisadas por metaloporfirinas via cromatografia gasosa/espectrometria de massas; Analysis of triazines oxidation with 'H IND.2 O IND.2'and catalyzed by metalloporphryns by gas chromatography/mass spectrometry

Kelly Adriana Ribeiro Tagliaferro
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 24/02/2015 PT
Relevância na Pesquisa
27.411133%
Os resíduos de herbicidas triazínicos são compostos com moderada toxicidade, altamente persistentes no ambiente, contaminando os mananciais e águas subterrâneas e são muito utilizados em várias culturas, inclusive da cana-de-açúcar. Os herbicidas atrazina e simazina foram oxidados com 'H IND.2O IND.2' na presença de catalisadores biomiméticos (metaloporfirinas de ferro e rutênio) e os produtos gerados na reação foram analisados via cromatografia gasosa (GC, do inglês gás chromatography) associada à espectrometria de massas (MS, do inglês mass spectrometry), buscando elucidar os subprodutos. As reações de oxidação dos herbicidas triazínicos e os subprodutos gerados foram monitoradas por espectrofotometria na região do ultra violeta e visível (UV-Vis) e cromatografia gasosa (GC), utilizando-se o detector de captura de elétrons (ECD, do inglês elétron capture detector). Os rendimentos das reações de oxidação das triazinas com 'H IND.2O IND.2' e catalisadas pelas metaloporfinas de ferro (Fe(FTTPCl)) e rutênio (Ru(OCTTPP)), variaram de acordo com as condições de reações catalíticas. Foi observado que houve degradação significativa dos analitos (94,70% para a atrazina e 92,60% para a simazina utilizando a (Fe(FTTPCl)) e; 94...

Implantação do plano de gestão de resíduos químicos da FT-UNICAMP : oxidação de herbicidas triazínicos com 'H IND. 2 O IND 2' e metaloporfirinas; Implantation of chemical waste management plan of FT-UNICAMP : oxidation of triazine herbicides with 'H IND. 2 IND 2 'and metalloporphyrins

Flávia Ferreira de Souza dos Santos
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 22/02/2011 PT
Relevância na Pesquisa
37.596604%
Os resíduos químicos gerados em laboratórios de universidades são complexos devido a grande diversidade dos processos de geração e dos compostos que os constituem. Dessa forma, há necessidade de um plano de gestão para evitar que esses resíduos de composição diversificada sejam dispostos inadequadamente no meio ambiente. Nesse contexto encontra-se em implantação o Plano de Gestão de Resíduos Químicos (PGRQ) dos Laboratórios de Ensino e Pesquisa da Faculdade de Tecnologia - FT/UNICAMP. Com a finalidade de contribuir para a implantação do PGRQ da FT, o presente projeto visou realizar ações de gestão, tais como o diagnóstico qualitativo e quantitativo dos resíduos gerados em todos os laboratórios da FT, buscar ações de minimização de geração, a divulgação do programa de gestão à comunidade acadêmica usuária dos laboratórios e a avaliação de possíveis alternativas de tratamento de resíduos. O levantamento periódico dos resíduos permitiu traçar o perfil de geração dos laboratórios da FT, fundamental para a implantação do plano de gerenciamento. A primeira transferência de resíduos ao abrigo externo e o oferecimento do curso de capacitação resultaram na redução da quantidade de resíduos gerados. No laboratório de cromatografia da FT tem sido realizado há alguns anos o monitoramento de herbicidas triazínicos em amostras ambientais...

Catalytic oxidation of organic compounds : a sustainable approach; Oxidação catalítica de compostos orgânicos : uma abordagem sustentável

Gomes, Sónia Maria
Fonte: Universidade de Aveiro Publicador: Universidade de Aveiro
Tipo: Tese de Doutorado
ENG
Relevância na Pesquisa
27.411133%
One of the biggest challenges for organic chemistry researchers is the development of catalytic systems able to selectively oxidize organic compounds, under mild and environmental sustainable conditions. In fact, this is a transformation which nature operates with an extraordinary ability but is of remarkable difficulty for both academia and industry. Metalloporphyrins, as biomimetic models of cytochromes P450, are thus catalysts with great potential. After the first introductory chapter, where the above-mentioned concepts are fully discussed, some general features of porphyrin properties, synthetic methodologies and reactivity are presented in Chapter 2 of this dissertation. The synthetic routes to all the Mn(III) and Fe(III) porphyrins used as catalysts during the work are also discribed in this chapter. Chapter 3 is dedicated to the application of Mn(III) and Fe(III) metalloporphyrin complexes on the oxidative catalysis of organosulfur compounds (sulfides, benzothiophenes, dibenzothiophenes and 1,3-di-hydrobenzothiophenes) by hydrogen peroxide. Besides revealing a high efficient approach for the obtention of the corresponding sulfones, the use of mild and nontoxic conditions turns this approach environmentally safe. The potentiality of the developed methodology only can be fully recognized through the heterogenization of porphyrin complexes in a solid support. So...