Search results for "DIACETYL"

1981

Diacetylene polymerization on a bulk insulator surface

2017

| openaire: EC/FP7/610446/EU//PAMS Molecular electronics has great potential to surpass known limitations in conventional silicon-based technologies. The development of molecular electronics devices requires reliable strategies for connecting functional molecules by wire-like structures. To this end, diacetylene polymerization has been discussed as a very promising approach for contacting single molecules with a conductive polymer chain. A major challenge for future device fabrication is transferring this method to bulk insulator surfaces, which are mandatory to decouple the electronic structure of the functional molecules from the support surface. Here, we provide experimental evidence for…

Compound Membranes of Linearly Polymerized and Cross-Linked Macrolipids with Phospholipids: Preparation, Microstructure and Applications

1985

Methods for the assembly and for studying the structural and dynamic properties of partially polymerized membranes are described. Mixtures of two classes of polymerizable amphiphiles with diacyl phosphatidylcholines are studied: (1) phosphatidylcholines carrying a diacetylene group per chain (abbreviated as (m,n)-DIINPC (where m + n + 6 equals number of C-Atoms per chain) and (2) a phospholipid-like molecule with a polymerizable methacryl ligand connected to the phosphate head group via (CH2CH2O)m spacers which is abbreviated as (m.n)-POMECY (n = number of C-atoms per chain). — Phase diagrams of the lipid mixtures are established by static light scattering in combination with freeze fractur…

Material transport and organizing phenomena of Langmuir—Blodgett membranes from polymerizable built up diacetylene amphiphiles on hydrophobic supports

1986

Abstract Langmuir—Blodgett multilayers of polymerized diin amphiphiles on different porous, hydrophobic ultrafilters have been studied as composite membranes under the conditions of reverse osmosis. Influences of differently structured surfaces of the supports on structure and phase change occurring during polymerization have been investigated by scanning electron microscopy and X-ray diffraction and are discussed with reverse osmosis data. When conditioned, fine porous hydrophobic supports become permeable to aqueous solutions at low pressures. Under these conditions permeate flux and retention were found to depend on the number of layers deposited.

On-surface synthesis on a bulk insulator surface

2018

On-surface synthesis has rapidly emerged as a most promising approach to prepare functional molecular structures directly on a support surface. Compared to solution synthesis, performing chemical reactions on a surface offers several exciting new options: due to the absence of a solvent, reactions can be envisioned that are otherwise not feasible due to the insolubility of the reaction product. Perhaps even more important, the confinement to a two-dimensional surface might enable reaction pathways that are not accessible otherwise. Consequently, on-surface synthesis has attracted great attention in the last decade, with an impressive number of classical reactions transferred to a surface as…

Surface characterization of functional poly(diacetylene) and poly(butadiene) mono- and multilayers

1982

The surface properties of Langmuir-Blodgett mono- and multilayers of a variety of amphiphilic poly(diacetylene)s and poly(butadiene)s were investigated by contact angle, streaming potentialζ, ellipsometry, and X-ray photoelectron spectroscopic (XPS) measurements. Captive air and octane angles varied between approximately 60° and 105° for hydrophobicx-layers and 31° to 46° for hydrophilic surfaces depending on the particular head group, whereas advancing angles determined via the vertical plate method are considerably higher. Negative streaming potentials were obtained for all surfaces. Positively charged monolayers yielded less negativeζ- potential values (−28 mV) than negatively charged (−…

Diacetylene Linked Anthracene Oligomers Synthesized by One-Shot Homocoupling of Trimethylsilyl on Cu(111)

2018

On-surface chemical reaction has become a very powerful technique to conjugate small precursor molecules and several reactions have been proposed with the aim to fabricate functional nanostructures on surfaces. Here we present an unforeseen adsorption mode of 9,10-bis-((trimethylsilyl)ethynyl)anthracene on a Cu(111)surface and the resulting one-shot desilylative homocoupling of of the adsorbate by annealing at 400 K. With a combination of high-resolution atomic force microscopy and density functional theory calculations, we found that the triple bonds and silicon atoms of the monomer chemically interact with the copper surface. After the oligomerization, we discovered that the anthracene un…

CCDC 915981: Experimental Crystal Structure Determination

2014

Related Article: Inguna Goba, Baiba Turovska, Sergey Belyakov, Edvards Liepinsh|2014|J.Mol.Struct.|1074|549|doi:10.1016/j.molstruc.2014.06.044

Mutation of the oxaloacetate decarboxylase gene of Lactococcus lactis subsp. lactis impairs the growth during citrate metabolism

2007

 ; Aims: Citrate metabolism generates metabolic energy through the generation of a membrane potential and a pH gradient. The purpose of this work was to study the influence of oxaloacetate decarboxylase in citrate metabolism and intracellular pH maintenance in relation to acidic conditions. Methods and Results: A Lactococcus lactis oxaloacetate decarboxylase mutant [ILCitM (pFL3)] was constructed by double homologous recombination. During culture with citrate, and whatever the initial pH, the growth rate of the mutant was lower. In addition, the production of diacetyl and acetoin was altered in the mutant strain. However, our results indicated no relationship with a change in the maintenanc…

Effect of 2,4-Diacetylphloroglucinol on Pithium : cellular responses and variation in sensitivity among propagules and species

2003

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