5,060 research outputs found
Sistema de plantio solteiro e consorciado na produção de hortaliças no Vale do São Francisco.
Suplemento. Edição dos Anais do 52 Congresso Brasileiro de Olericultura, Salvador, jul. 201
Imidazo-benzo-15-crown-5 ether bearing arylthienyl and bithienyl moieties as novel fluorescent chemosensors for Pd2+ and Cu2+
Novel fluorescent ionophores bearing imidazo-arylthienyl or imidazo-bithienyl pi-conjugated bridges functionalized with one or two fused benzo-15-crown-5 ethers as receptor units are reported. The sensing ability of the compounds in the presence of metallic cations (Li+, Na+, K+, Ca2+, Zn2+, Cu2+, Ni2+, Pd2+ and Hg2+) and fluoride ion was studied in MeCN/DMSO solutions by absorption and emission spectroscopy. The experimental results indicate that all compounds could act as selective fluorimetric sensors for Cu2+ and Pd2+ and also for the fluoride ion, in the case of the bis-substituted crown ether derivatives.Fundação para a Ciência e a Tecnologia (FCT) - PTDC/QUI/66250/2006 (FCOMP-01-0124-FEDER-007428), SFRH/BD/36396/200
Synthesis and evaluation of bipendant-armed (oligo)thiophene crown ether derivatives as new chemical sensors
Three new (oligo)thiophene bipendant-armed ligands 2a-c, derived from 2-(aminomethyl)-15-crown-5, have been synthesized and characterized. Compounds 2a-c were prepared by reductive amination of the corresponding macrocycle with formyl thiophene derivatives 1a-c in the presence of NaBH(OAc)3 in fair to good yields. The photophysical properties of ligands 2a-c were studied and they were also evaluated as chemosensors in the presence of Na(I), Ag(I), Pd(II) and Hg(II) cations in acetonitrile solution.Fundação para a Ciência e a Tecnologia (FCT
Synthesis and solvatochromism studies of novel bis(indolyl)methanes bearing functionalized arylthiophene groups as new colored materials
The demand for dyes with solvatochromic properties has increased in the last few years, mainly due to their wide range of applications in the analytical and industrial fields, such as in the textile industry. The phenomenon of solvatochromism is associated with the differential solvation of the ground and excited states of the solvatochromic compounds, leading to an important tool for the study of the nature of solute–solvent interactions. In this paper we report the synthesis of new bis(indolyl)methane derivatives bearing arylthiophene spacers (2a–d) functionalized with electron-donating and electron- withdrawing groups, and the photophysical studies in different solvents, such as ethanol, acetonitrile, dichloromethane, trichloromethane, dimethylsulfoxide, diethylether and 1,4-dioxane. Aiming to explore their solvatochromic behavior in the ground and excited states, all solvents employed have different hydrogen-bond donor abilities. The largest colour modifications were visualized for compound 2b, the solution colours of which are orange in DMSO, blue in trichloromethane, green in dichloromethane and purple in 1,4-dioxane. A negative solvatochromism was observed in 2b and positive one in 2a, 2c and 2d.Fundação para a Ciência e a Tecnologia (FCT
(Oligo)thienyl-imidazo-benzocrown ether derivatives : synthesis, photophysical studies and evaluation of their chemosensory properties
A series of novel (oligo)thienyl-imidazobenzocrown ethers were synthesised through a simple method and evaluated as fluorimetric chemosensors for transition metal cations. Interaction with Ni2+, Pd2+, and Hg2+ in ACN/DMSO solution (99:1) was studied by absorption and emission spectroscopy. Chemoselectivity studies in the presence of Na+ were also carried out and a fluorescence enhancement upon chelation (CHEF) effect was observed following Hg2+ complexation. Considering that most systems using fluorescence spectroscopy for detecting Hg2+ are based on the complexation enhancement of the fluorescence quenching (CHEQ) effect, the present work represents one of the few examples for sensing of Hg2+ based on a CHEF effect.Fundação para a Ciência e a Tecnologia (FCT) - PTDC/QUI/66250/2006, SFRH/BD/36396/2007, SRFH/BPD/72557/201
Rendimento de óleo essencial de manjericão em função de diferentes sistemas de plantio.
Suplemento. Edição dos Anais do 52 Congresso Brasileiro de Olericultura, Salvador, jul. 201
Pathological, Morphological, Cytogenomic, Biochemical and Molecular Data Support the Distinction between Colletotrichum cigarro comb. et stat. nov. and Colletotrichum kahawae
The genus Colletotrichum has witnessed tremendous variations over the years in the number of species recognized, ranging from 11 to several hundreds. Host-specific fungal species, once the rule, are now the exception, with polyphagous behavior regarded as normal in this genus. The species Colletotrichum kahawae was created to accommodate the pathogens that have the unique ability to infect green developing coffee berries causing the devastating Coffee Berry Disease in Africa, but its close phylogenetic relationship to a polyphagous group of fungi in the C. gloeosporioides species complex led some researchers to regard these pathogens as members of a wider species. In this work we combine pathological, morphological, cytogenomic, biochemical, and molecular data of a comprehensive set of phylogenetically-related isolates to show that the Coffee Berry Disease pathogen forms a separate species, C. kahawae, and also to assign the closely related fungi, previously in C. kahawae subsp. cigarro, to a new species, C. cigarro comb. et stat. nov. This taxonomic clarification provides an opportunity to link phylogeny and functional biology, and additionally enables a much-needed tool for plant pathology and agronomy, associating exclusively C. kahawae to the Coffee Berry Disease pathogen.info:eu-repo/semantics/publishedVersio
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