Search results for "Macromolecular Substance"
showing 10 items of 882 documents
Binding and Fluorescent Sensing of Dicarboxylates by a Bis(calix[4]pyrrole)-Substituted BODIPY Dye
2013
A bis(calix[4]pyrrole)-substituted BODIPY ditopic receptor 1 has been synthesised and characterised. The binding and sensing properties of 1 towards several aliphatic and aromatic dicarboxylates have been evaluated by using UV/Vis fluorescence and 1H NMR spectroscopy. The receptor strongly binds linear α,ω-dicarboxylates of appropriate lengths (C9 and C10) by acting as a cleft. For all dicarboxylates, the binding event is detected by a bathochromic shift in the UV/Vis spectra of the receptor and by strong quenching of its fluorescence.
Pharmakologisch aktive polymere, 5. Modellreaktionen zur umsetzung von pharmaka und enzymen mit monomeren und polymeren reaktiven estern
1973
Die Darstellung reaktiver Ester der Acryl-, Methacryl- und N-Vinylcarbaminsaure wird beschrieben. Die Verbindungen sind im Gegensatz zu anderen reaktiven Saurederivaten wie Saurechloriden, -anhydriden und Isocyanaten kristalline Monomere, die gut zu handhaben sind. Sie lassen sich leicht zu unvernetzten, loslichen Polymeren homo- und copolymerisieren. Die Copolymerisationsparameter wurden bestimmt. Entsprechend wie die aus der Peptidchemie bekannten reaktiven Ester reagieren sie in monomerer wie in polymerer Form bei niedriger Temperatur selektiv und schonend mit Nucleophilen in guten Ausbeuten, z. B. mit Aminen in wasriger Losung. Dies eroffnet die Moglichkeit zur nebenreaktionsfreien Bind…
Macromolecules with groups of high reactivity
1960
Reactions on the reactive groups of macromolecular substances (e.g., cellulose) have long been known, even since before the structures of macromolecules were understood. H. Staudinger carried out numerous reactions with macromolecules, maintaining the degree of polymerization constant, in order to substantiate the macromolecular structure of the substances investigated (polymeric-analogous reactions). During the last fifteen years reactions with macromolecules have been investigated because it was desirable to compare the chemical diversity of low molecular weight compounds with the corresponding chemical diversity of macromolecular compounds. These endeavors bring forth materials which sup…
Light Regulation of the Thylakoid LHCII Protein Phosphorylation at the Substrate Level
1998
The distribution of light energy between the two photosystems as well as the light-induced turnover of PSII proteins are regulated by the reversible phosphorylation of LHCII and the PSII-core proteins. The thylakoid protein kinase(s) is activated by a signal transduction system involving the interaction of reduced plastoquinone with the quinol oxidation site of the cytochrome bf complex [1]. Phosphorylation of the mobile pool of LHCII induces dissociation of this antenna from PSII and allows its interaction with the PSI in the stroma exposed membranes (state transition)[21. Dephosphorylation of LHCII by a membrane -bound phosphatase appears to be regulated by a cyclophilinlike protein locat…
Biosensors Applied to Quantification of Ethanol in Beverages
2019
Abstract The quality control in the processing of alcoholic beverages is major concern for producers and regulatory agencies, particularly for ethanol content which is mandatory in the label of alcoholic beverages in many countries. The use of biosensors can be of great interest in this context that usually requires laborious and costly protocols. Biosensors are composed by two principal components: the biological recognition element and the transducer. Particularly for ethanol evaluation, the use of alcohol dehydrogenase (ADH) or oxidase (AOX) is commonly reported in the literature which allowed the production of optical and electrochemical biosensors. These biosensors can aid in the deter…
Monomeric vs. polymeric bonded iminodiacetate silica supports in high-performance ligand-exchange chromatography
1983
The synthesis of monomeric and polymeric bonded iminodiacetate-groups on silica supports is described. The polymeric support offers advantages over the monomeric, such as (i) preparation is much simpler, (ii) higher surface concentration of functional groups can be achieved without loss of efficiency and (iii) hydrolytic stability. Cu2+ loaded supports were examined for their kinetic performance, in particular for the C-parameter of the Knox equation, and for their hydrolytic stability. Calculation of the surface coverage shows that only a rather thin polymeric layer is formed; this is in agreement with the results of the kinetic performance. The retention of α-amino acids on the Cu2+ loade…
Preparation and Recycling of Plasticized PLA
2010
Poly(lacticacid)(PLA)hasbeengainingarisinginterestoverthe last years as a biodegradable and environmental-friendly substitute of traditional non-biodegradable poly-mers.Several ways exist to synthesize PLA, however, poly-merization through lactide formation is the most used onindustrial scale, allowing to obtain optimum results interms of mechanical and thermal properties.
N-trifluoracetyl-nylon 66 als polymeres reagenz
1979
N-Trifluoroacetyl-Nylon 66 (2) obtained by the reaction of Nylon 66 (1) with trifluoroacetic anhydride is very suitable as a polymeric reagent for the trifluoroacetylation of amines and alcohols. The advantages of 2 compared with low molecular trifluoroacetylating reagents are discussed. The selectivity against different substituted anilines and against structurally isomeric secondary amines was studied intensively by kinetic measurements.
An approach to polymer-supported triplet benzophenone photocatalysts. Application to sustainable photocatalysis of an α-diazocarbonyl compound
2013
Covalent immobilization of 4-hydroxybenzophenone on Merrifield resins affords new heterogeneous polymeric triplet photocatalysts. Their successful application in the intramolecular triplet-sensitized photolysis of a α-diazo β-keto ester has been achieved under sustainable criteria. Remarkably, the simple recovery and reuse for up to five sequential applications have been performed, although resulting in a slightly decreasing activity.
Surfactant-assisted chromogenic sensing of cyanide in water
2009
Chromogenic cyanide recognition in water was achieved by the use of a hydrophobic dye in micellar containers.