Search results for "Conjugated"

Pentadecamer 2,5-Dipropoxy-1,4-phenylenevinylene

2002

The conjugated, all-(E)-configured pentadecamer 2,5-dipropoxy-1,4-phenylenevinylene 1j was prepared by a multistep synthesis on the basis of hydroquinone. The procedure consists of a general method for the repetitive extension of oligo(phenylenvinylene) chains by two styryl units (7a ⇄ 10 ⇄ 12 ⇄ 14). The relatively rigid oligomer 1j represents a molecular wire of about 100 A. The absorption of 1j provides a proof for the convergence theory for electronic properties of conjugated oligomers with increasing number of repeat units. The corresponding conjugated polymer 1p with the same substitution matches the values which were extrapolated from the oligomer series 1a−1j. (© Wiley-VCH Verlag Gmb…

Practical Synthesis of Vinyl-Substitutedp-Phenylenevinylene Oligomers and Their Triethoxysilyl Derivatives

2001

Luminescent semiconducting organic compounds are widely used as active layers in electro-optical devices. Apart from conjugated polymers, monodisperse oligomers also represent attractive materials. The synthesis of stilbenoid oligomers with polymerizable end groups is presented. Oligo(phenylenevinylene)s with terminal vinyl groups 17–19 are prepared in good yields by Horner–Emmons olefinations or by the Heck reaction of the iodo-substituted oligomers 15, 16 with compressed ethene. Triethoxysilyl groups can be linked via rigid 1,2-vinylene units to the chromophores 26–30, either in the direct reaction of 14, 24 with silanes 21, 22 or by cross-metathesis of 17–19 with the vinylsilanes 21, 22 …

Isomerization of 9c11t/10t12c CLA in Triacylglycerols

2010

Published version of an article in the journal: Lipids . The original publication is available at Spingerlink. http://dx.doi.org/10.1007/s11745-010-3452-x Isomers of conjugated linoleic acid from 7t9c through 12t14t can be induced by thermal treatment of triacylglycerol samples of 9c11t or 10t12c fatty acids in glass tubes. The formation of conjugated linoleic acids (CLAs) has been observed during thermal induction of the above-mentioned triacylglycerols at 250, 280 and 320A degrees C. The concentrations of isomers formed in the mixture varied depending on the temperature and duration of the heating experiments. The objective of this study was to find a suitable thermal induction temperatur…

Self-assembly of fluorescent diimidazolium salts: tailor properties of the aggregates changing alkyl chain features

2016

Searching for new fluorescent organic salts to be used in biomedical and electrochemical field, we conjugated properties of imidazolium salts with the ones of naphthalene diimide core and we obtained some N,N′-bis-(1-alkyl-3-propylimidazolium)naphthalene diimide diiodides. We took into account alkyl chains going from hexyl to dodecyl, as well as hydrogenated and fluorinated alkyl tails. After determination of their thermal behaviour by differential scanning calorimetry, concentration-, and temperature-dependent spectroscopic studies (UV-vis and fluorescence) were performed evidencing the occurrence of isodesmic and enthalpy-driven self-assembly processes. Properties of aggregates were also …

Effect of ewe feeding system (grass v. concentrate) on intramuscular fatty acids of lambs raised exclusively on maternal milk

2005

AbstractTwenty pregnant Comisana ewes were divided into two groups of 10. One group was allowed to graze a vetch pasture (grass). The second group of animals was housed collectively in a pen and was given hay and concentrates (concentrate). After lambing, all the ewes were allowed to stay with the respective lambs between 18:00 h and 07:00 h of the following day in two different pens. Therefore all the lambs were raised exclusively on maternal milk. The lambs were slaughtered at 38 days of age. Milk and lamb meat (longissimus dorsi muscle) fatty acids were analysed. Ewes on grass produced milk with a lower (P< 0·001) proportion of saturated fatty acids and with a higher proportion of bot…

Synthesis of Microporous Carbon Nanofibers and Nanotubes from Conjugated Polymer Network and Evaluation in Electrochemical Capacitor

2009

One-dimensional fibers and tubes are constructed through the oriented carbon-carbon cross-linking reactions towards rigid conjugated polymer networks. As the result, a template-free and one-step synthesis of CNTs and CNFs is achieved through a simple carbonization of the as-formed carbon-rich tubular and fiberlike polyphenylene precursors under argon. Microporous CNTs and CNFs with a surface area up to 900 m2 g–1 are obtained, together with HR-TEM characterizations indicating the formation of intrinsic microporous structure in these rigid carbon-rich networks. The primary electrochemical experiments reveal their promising applications as advanced electrodes in electrochemical double-layered…

The folding of individual conjugated polymer chains during annealing.

2011

New n-dopable thiophene based polymers

1999

Abstract New conjugated polymers containing variable amounts of thienyl and thienyl-S,S-dioxide units have been prepared by chemical or electrochemical polymerization of the appropriate substrates. The presence of the thienyl S,S-dioxide units leads to the decrease of the LUMO energies with respect to those of the ‘all thienyl’ counterparts. Electrochemical and spectro electrochemical data of n-doping of these materials are reported.

Polydithienothiophenes: Two new conjugated materials with narrow band gap

1997

Abstract The electrochemical polymerisation of dithieno[3,4-b:3',2'-d]thiophene and dithieno[3,4-b:2',3'-d]thiophene leads to conjugated materials with narrow band gap in which the p- and n-doping processes are possible in organic electrolytes. The spectroelectrochemical study of these polymers is reported.

Defects and defect engineering in Soft Matter.

2020

Soft matter covers a wide range of materials based on linear or branched polymers, gels and rubbers, amphiphilic (macro)molecules, colloids, and self-assembled structures. These materials have applications in various industries, all highly important for our daily life, and they control all biological functions; therefore, controlling and tailoring their properties is crucial. One way to approach this target is defect engineering, which aims to control defects in the material's structure, and/or to purposely add defects into it to trigger specific functions. While this approach has been a striking success story in crystalline inorganic hard matter, both for mechanical and electronic properti…