Chiral Polymers
Mostrando 1-12 de 13 artigos, teses e dissertações.
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1. Síntese e caracterização de novos polímeros líquido-cristalinos de cadeia lateral derivados do heterociclo 2-isoxazolínico 3,5-dissubstituído
This thesis presents the synthesis and characterization of new polymer liquid crystal materials based on heterocycle 2-isoxazoline 3,5-disubstituted. We studied the inversion effects of groups linked in position 3 and 5 in 2-isoxazoline in the mesogenic group attached by side chain polymer liquid crystal and the influence in liquid crystals properties. The m
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 2012
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2. Utilização do D-manitol em síntese orgânica
D-mannitol is used in several fields including food, pharmaceuticals, cosmetics and textiles being an important carbohydrate found widespread in nature. Due to its chirality, it is largely used in organic synthesis with several applications, such as ligands, polymers, chiral pool, for preparation of small chiral building blocks, key intermediates in total sy
Química Nova. Publicado em: 2009
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3. Molecularly imprinted polymers (MIPs) as solid phase extractors in flow systems / Polímeros molecularmente impressos (MIPs) como extratores em fase sólida em sistemas de análises em fluxo
Molecularly imprinted polymers (MIPs) are promising as material to be used in solid phase extractions due to their high selectivity. MIPs selectivity is directly related to the recognition of a molecule of interest, which was previously employed as template in the synthesis process. The main favorable characteristics of MIPs are the easy preparation, low cos
Publicado em: 2008
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4. PolÃmeros quirais : polipirrÃis e politiofenos modificados com R-(-) ou S-(+)-N-(3,5-Dinitrobenzoil)- α-fenilglicina
Os monÃmeros de R(-) e S(+)-N-(3,5-dinitrobenzoil)-α-fenilglicinato de 3-(1- pirrolil)propila [R(-)DNBP e S(+)DNBP] e de R(-) e S(+)-N-(3,5-Dinitrobenzoil)-α- fenilglicinato de 2-(3-tienil)etila [R(-)DNBT e S(+)DNBT] foram sintetizados, caracterizados e polimerizados em clorofÃrmio usando FeCl3 como agente oxidante. As massas moleculares mÃdias,
Publicado em: 2007
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5. Chirality and helicity of poly-benzyl-L-glutamate in liquid crystals and a wave structure that mimics collagen helicity in crimp
Ideal biocompatible polymers must show a mimetic superstructure with biological supra-organization. Collagen-rich structures like tendons and ligaments are materials with various levels of order, from molecules to bundles of fibers, which affect their biomechanical properties and cellular interactions. Poly-benzyl-L-glutamate (PBLG) displaying helicity was u
Materials Research. Publicado em: 2001-07
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6. Helically chiral polymers: A class of ligands for asymmetric catalysis
Helically chiral polymers from achiral monomers containing N and P atoms have been shown to be ligands for transition metals such as Pd and Rh. The Rh complex of the phosphane-containing polyisocyanate p(18-co-17) was an active albeit hardly enantioselective catalyst in the asymmetric hydrogenation of the dehydro amino acid N-acetamidocinnamic acid (15% enan
National Academy of Sciences.
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7. NMR determination of the major solution conformation of a peptoid pentamer with chiral side chains
Polymers of N-substituted glycines (“peptoids”) containing chiral centers at the α position of their side chains can form stable structures in solution. We studied a prototypical peptoid, consisting of five para-substituted (S)-N-(1-phenylethyl)glycine residues, by NMR spectroscopy. Multiple configurational isomers were observed, but because of extensiv
The National Academy of Sciences.
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8. Liquid crystalline phases in concentrated aqueous solutions of Na+ DNA.
Concentrated aqueous saline solutions of short (146-base-pair) DNA fragments suddenly become turbid and iridescent when the DNA concentration is slightly increased or the temperature is decreased. Microscopic examination through crossed polarizing filters shows that turbidity and iridescence is due to formation of a liquid crystalline DNA phase similar to ch
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9. Sequence-specific polypeptoids: A diverse family of heteropolymers with stable secondary structure
We have synthesized and characterized a family of structured oligo-N-substituted-glycines (peptoids) up to 36 residues in length by using an efficient solid-phase protocol to incorporate chemically diverse side chains in a sequence-specific fashion. We investigated polypeptoids containing side chains with a chiral center adjacent to the main chain nitrogen.
The National Academy of Sciences.
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10. Hierarchical formation of helical supramolecular polymers via stacking of hydrogen-bonded pairs in water
Bifunctional ureido-s-triazines provided with penta(ethylene oxide) side chains are able to self assemble in water, leading to helical columns via cooperative stacking of the hydrogen-bonded pairs (DADA array). Monofunctional ureido-s-triazines do not form such helical architectures. The presence of a linker, covalently connecting the two ureido-s-triazine u
National Academy of Sciences.
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11. Electron microscopic study of supramolecular liquid crystalline polymers formed by molecular-recognition-directed self-assembly from complementary chiral components.
Electron microscopic observation provides insight into the nature of the polymeric supramolecular liquid crystalline species (TP2, TU2)n formed by polyassociation of the complementary components TP2 and TU2 derived from D-, L-, or meso-tartaric acid (where T is any form of tartaric acid, D is the D species, and L is the L species) and from pyridine (P) and u
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12. Polyester Biosynthesis Characteristics of Pseudomonas citronellolis Grown on Various Carbon Sources, Including 3-Methyl-Branched Substrates
Forty-two different carbon sources were tested for the polyester synthesis of a citronellol-utilizing bacterium, Pseudomonas citronellolis (ATCC 13674). These included linear C2 to C10 monocarboxylic acids, C3 to C10 dicarboxylic acids, saccharides, α,ω-diols, hydrocarbons, and 3-methyl-branched substrates such as 3,7-dimethyl-6-octen-1-ol (citronellol), 3