11 research outputs found
Interaction of Fe3+ meso-tetrakis (2,6-dichloro-3-sulfonatophenyl) porphyrin with cationic bilayers: magnetic switching of the porphyrin and magnetic induction at the interface
An organized multilayer was constructed by the layer-by-layer technique in which alternating layers of metalloporphyrin and dioctadecyldimethylammonium bromide bilayers were deposited onto an indium tin oxide surface electrode. The porphyrin molecules that are organized in the different layers showed a strong electroactivity with a well-defined electrochemical process. In LbL, electroactivity could be explained only by the occurrence of electron hoping. Thus, total Kohn–Sham density functional theory (KS-DFT) was performed to better understand the conditions responsible for the electroactivity of the metalloporphyrin layers intercalated by an insulating material. Total KS-DFT theory involves local density approximation energy calculations based on spin-polarized variant of KS-DFT theory. The results revealed a magnetization switching of the metalloporphyrin induced by the interaction with the surfactant bilayer accompanied by spin polarization of the porphyrin-interacting surfactant molecule. Although discrete, the surfactant magnetization had significant repercussions on the electron conductivity. Calculations also demonstrated loss of porphyrin symmetry promoted by a parent surfactant with a shorter hydrocarbon chain, ditetradecyldimethylammonium bromide. The calculation results were corroborated by experimental results obtained by the electron paramagnetic resonance and magnetic circular dichroism techniques.FAPESPCNPqCAPE
Molecular interactions and structure of a supramolecular arrangement of glucose oxidase and palladium nanoparticles
This paper presents studies about the molecular interactions and redox processes involved in the formation of palladium nanoparticles associated to glucose oxidase (GOx-PdNPs) in a supramolecular arrangement. the synthesis occurs in two steps, the Pd reduction and the formation of the 80 nm sized supramolecular aggregates containing multiples units of GOx associated to 3.5 nm sized PdNPs. During synthesis, GOx molecules interact with Pd salt leading to metal ion and FAD reduction probably via the thiol group of the cysteine 521 residue. for the growing of PdNPs, formic acid was necessary as a co-adjuvant reducing agent. Besides the contribution for the redox processes, GOx is also necessary for the NP stability preventing the formation of precipitates resulted from uncontrolled growing of NPs Cyclic voltammetry of the GOx-PdNPs demonstrated electroactivity of the bionanocomposite immobilized on ITO (indium-tin oxide) electrode surface and also the NP is partially blocked due to strong interaction GOx and the surface of PdNPs. Vibrational spectroscopy (FTIR) showed that significant structural changes occurred in GOx after the association to PdNP. These mechanistics and structural studies can contribute for modulation of bionanocomposites properties.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Instituto Nacional em Eletronica Organica (INEO)Univ Fed ABC, Ctr Ciencias Nat & Humanas, BR-09210170 Santo Andre, BrazilUniv Fed Piaui, Ctr Ciencias Nat, Dept Quim, BR-64049550 Teresina, PI, BrazilUniversidade Federal de São Paulo, Dept Biol Mol, BR-04044020 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biol Mol, BR-04044020 São Paulo, BrazilFAPESP: 2009/15558-1FAPESP: 2008/04849-6Web of Scienc
Nano-Assembled Supramolecular Films from Chitosan-Stabilized Gold Nanoparticles and Cobalt(II) Phthalocyanine
In this work, we report the synthesis and characterization of gold nanoparticles (AuNPs) stabilized with chitosan (Chit), as well as the capability of this material to form multilayer films with cobalt(II) tetrasulfonated phthalocyanine (CoTsPc). The new hybrid material based on Chit-AuNPs and CoTsPc was characterized by several techniques, and the electrochemical properties of an ITO (indium tin oxide) electrode modified with Chit-AuNPs and CoTsPc were investigated. Chit prevented AuNPs (diameter of 6.0 nm) agglomeration, forming a colloidal suspension that was stable for months. The interaction between the AuNPs and Chit molecules occurs mainly through the CH2 and NH3+ groups from Chit. Supramolecular interaction was observed for multilayer films of Chit-AuNPs/CoTsPc, and the AuNPs influenced the redox properties of CoTsPc. The presence of the nanoparticles not only increased the electroactive area of the electrodes, but also the rate of charge-transfer, suggesting that this material is a very promising candidate for further applications in electrochemical devices
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This study was supported by Agencia Nacional de Promoción Científica y Técnica (ANPCyT) grant no. PICT-2017-4203 and Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), and a postdoctoral fellowship from CONICET to AVR.Fil: Marhold, Karol. Slovak Academy of Sciences. Institute of Botany; Eslovaquia. Karlova Univerzita (cuni); República ChecaFil: Kucera, Jaromír. Slovak Academy of Sciences. Institute of Botany; EslovaquiaFil: Acuña, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Botánica del Nordeste. Universidad Nacional del Nordeste. Facultad de Ciencias Agrarias. Instituto de Botánica del Nordeste; ArgentinaFil: Akopian, Janna A.. Armenian National Academy of Sciences; ArmeniaFil: de Almeida, Erton M.. Universidade Federal de Pernambuco; Brasil. Universidade Federal da Paraíba; BrasilFil: Alves, Marccus V.. Universidade Federal da Paraíba; BrasilFil: Amorim, Bruno. Museu da Amazônia; Brasil. Universidade do Estado do Amazona; BrasilFil: An'kova, Tatyana V.. Academia de Ciencias de Rusia; RusiaFil: Arora, Jaya. University of Delhi; IndiaFil: Aytaç, Zeki. Gazi Üniversitesi; TurquíaFil: Baez, Jesica Mariana. Universidade Federal de Pernambuco; Brasil. Leibniz Institute of Plant Genetics and Crop Plant Research; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Cavalcanti, Taciana Barbosa. Parque Estação Biológica; BrasilFil: Calvente, Alice. Universidade de Sao Paulo; Brasil. Universidade Federal do Rio Grande do Norte; BrasilFil: Catalan, Pilar. Tomsk State University; Rusia. Universidad de Zaragoza; EspañaFil: Chernyagina, Olga A.. Academia de Ciencias de Rusia; RusiaFil: Chernysheva, Olga A.. Academia de Ciencias de Rusia; RusiaFil: Cordeiro, Joel M. P.. Universidade Estadual da Paraiba; BrasilFil: Daviña, Julio Rubén. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Deanna, Rocío. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas; Argentina. State University of Colorado at Boulder; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Delgado, Luis. Universidad de Salamanca; EspañaFil: Dias Silva, Yhanndra K.. Universidade Federal de Pernambuco; BrasilFil: Elliott, Tammy L.. University of Cape Town; Sudáfrica. University of Montreal; CanadáFil: Erst, Andrey S.. Tomsk State University; Rusia. Academia de Ciencias de Rusia; RusiaFil: Felix, Leonardo P.. Universidade Federal da Paraíba; BrasilFil: Forni Martins, Eliana R.. Universidade Estadual de Campinas; BrasilFil: Gallego, Francisca. Universidad de Salamanca; EspañaFil: Facco, Marlon Garlet. Universidade de Brasília; BrasilFil: Gianini Aquino, Analía Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; ArgentinaFil: Gomes de Andrade, Maria J.. Universidade do Estado da Bahia; BrasilFil: Rua, Gabriel Hugo. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Interaction of Fe3+meso-tetrakis (2,6-dichloro-3-sulfonatophenyl) porphyrin with cationic bilayers: magnetic switching of the porphyrin and magnetic induction at the interface
Growing knowledge: an overview of Seed Plant diversity in Brazil
Abstract An updated inventory of Brazilian seed plants is presented and offers important insights into the country's biodiversity. This work started in 2010, with the publication of the Plants and Fungi Catalogue, and has been updated since by more than 430 specialists working online. Brazil is home to 32,086 native Angiosperms and 23 native Gymnosperms, showing an increase of 3% in its species richness in relation to 2010. The Amazon Rainforest is the richest Brazilian biome for Gymnosperms, while the Atlantic Rainforest is the richest one for Angiosperms. There was a considerable increment in the number of species and endemism rates for biomes, except for the Amazon that showed a decrease of 2.5% of recorded endemics. However, well over half of Brazillian seed plant species (57.4%) is endemic to this territory. The proportion of life-forms varies among different biomes: trees are more expressive in the Amazon and Atlantic Rainforest biomes while herbs predominate in the Pampa, and lianas are more expressive in the Amazon, Atlantic Rainforest, and Pantanal. This compilation serves not only to quantify Brazilian biodiversity, but also to highlight areas where there information is lacking and to provide a framework for the challenge faced in conserving Brazil's unique and diverse flora