Search results for "amide"

Linked Benzylamido-Cyclopentadienyl Ligands: Synthesis and Characterization of Alkyl Titanium Complexes

1997

Titanium complexes of the general type Ti(η5:η1-C5H4Si-Me2NCH2C6H3X2-2,5)Cl2 (XH, F), containing a linked benzylamido-cyclopentadienyl ligand, were prepared by reaction of Ti(η5-C5H4SiMe2Cl)Cl3 with lithium amide Li(NHCH2C6H3X2-2,5). A single-crystal X-ray structural analysis of Ti(η5: η1-C5H4SiME2NCH2C6H3F2-2,5)Cl2 revealed a conformation in the solid state in which the aryl ring is turned away from the metal center. Ti(η5:η1-C5H4SiMe2NCH2C6H5)Cl2 can be alkylated with a variety of reagents to form extremely sensitive complexes of the type Ti(η5-C5H4SiMe,2NCH2C6H5)R2 (RMe, CH2 C6H5, CH2SiME3, CH2CMe2C6H5). Reaction of Li2[C5Me4SiMe2NCH2C6H5] with TiCl3(THF)3 gave Ti(η5: η1-C5Me4SiMe2NCH2C6…

2021

Six bile acid alkyl amide derivatives were studied with respect to their gelation properties. The derivatives were composed of three different bile acids with hexyl or cyclohexyl side chains. The gelation behaviour of all six compounds were studied for 36 solvents with varying polarities. Gelation was observed mainly in aromatic solvents, which is characteristic for bile-acid-based low molecular weight gelators. Out of 108 bile acid-solvent combinations, a total of 44 gel systems were formed, 28 of which from lithocholic acid derivatives, only two from deoxycholic acid derivatives, and 14 from cholic acid derivatives. The majority of the gel systems were formed from bile acids with hexyl si…

Time-resolved rheology as a tool to monitor the progress of polymer degradation in the melt state – Part II: Thermal and thermo-oxidative degradation…

2015

Abstract Thermal and thermo-oxidative degradation of nanocomposites based on polyamide 11 (PA11) and organo-modified clay (Cloisite® 30B) are studied in the melt state (T = 215 °C) via time-resolved mechanical spectroscopy (TRMS). The goal is assessing the potentiality of rheological analysis for studying polymer degradation in complex systems such as polymer nanocomposites, whose rheological response stems from the combination of the contributions of polymer and nanoparticles. We prove that a thorough analysis grounded on TRMS allows to isolate the effect of degradation of the polymer matrix, whose progress can be hence profitably monitored. Essentially the same degradation mechanisms as i…

A Deeper Insight into the Postpolymerization Modification of Polypenta Fluorophenyl Methacrylates to Poly(N -(2-Hydroxypropyl) Methacrylamide)

2014

This work provides a detailed insight into the synthesis of N-(2-hydroxypropyl)methacrylamide (HPMA) polymers employing the activated ester approach. In this approach, polypenta fluorophenyl methacrylate (PFPMA)-activated ester polymers are synthesized by the reversible addition-fragmentation chain transfer (RAFT) polymerization and transferred into HPMA-based systems by the use of 2-hydroxypropylamine. To prove quantitative conversion in the absence of side reactions, special attention is devoted to investigate different reaction conditions by different analytical methods ((1) H, (19) F, inverse-gated (13) C NMR, and zeta potential measurements). Furthermore the influence of common solvent…

Conformational studies of hexapeptides containing two dehydroamino acid residues in positions 2 and 5 in peptide chain

2008

Conformational preferences of a group of hexapeptides containing two dehydroamino acid residues in Positions 2 and 5 in peptide chain were investigated by means of spectroscopic methods (NMR and CD) and theoretical calculations. In the case of dimethylsulfoxide (DMSO) solution, only peptide with free N-termini adopted rigid 310-helical conformation, for the rest of examined peptides extended and “zig-zag” conformers were predominant. CD measurements showed that only in chloroform solution the conformational freedom of investigated peptides was restricted. © 2008 Wiley Periodicals, Inc. Biopolymers 89: 691–699, 2008. This article was originally published online as an accepted preprint. The “…

Proteins and enzymes of the peroxisomal membrane in mammals.

1993

Proteins of the peroxisomal membrane can be schematically divided into two groups, one being made up of more or less characterized proteins with generally unknown functions and the other consisting of enzyme activities of which the corresponding proteins have not been characterized. In the present report, these proteins and enzymes are described with the addition of unpublished results regarding their induction by peroxisome proliferators at the post-transcriptional level. Integral membrane proteins (IMPs) can be isolated using an alkaline solution of sodium carbonate. A dozen of preponderant IMPs can be seen on sodium dodecyl sulfate polyacrylamide gel electrophoresis, and the major band c…

Reactive nanorods based on activated esterpolymers: a versatile template-assisted approach for the fabrication of functional nanorods

2011

A new route for the fabrication of polymeric nanorods with functional moieties via post-modification of reactive nanorods is described. To this end reactive nanorods with a homogenous and narrow size distribution were fabricated by utilizing an anodic aluminium oxide (AAO) template-assisted approach. The nanorods are based on activated pentafluorophenyl esters, to enable quantitative post-modification with amines under very mild reaction conditions yielding the corresponding functionalized amide. Post-modification with fluorescent dyes as well as the conversion into well-dispersed rod-shaped poly(N-isopropylacrylamide) (PNIPAM) hydrogels that exhibit a thermal-responsive phase transition wa…

A Self-Assembled 2D Molecule-Based Magnet: The Honeycomb Layered Material {Co3Cl4(H2O)2[Co(Hbbiz)3]2}

2003

Research in the area of molecule-based magnets is rapidly expanding, owing, in part, to numerous breakthroughs in the past decade.[1] The preparation of solid-state architectures of varying dimensionalities from specifically tailored paramagnetic building blocks has proven to be very successful, and also clearly multidisciplinary. Materials science and supramolecular chemistry efforts have joined forces with classical organic and inorganic chemistry in the design of solid-state materials whose magnetic properties rival, and sometimes even exceed, those of classic inorganic solids.[2] The moleculebased strategy allows for the preparation of unusual materials that cannot otherwise be obtained…

Compatibilization of polyethylene/polyamide 6 blend nanocomposite films

2015

Polymer blends of incompatible components need to undergo compatibilization, in order to give rise to a blend with good physical properties. At the same way, polymer/clay nanocomposites show this problem because of different chemical nature of the polymer matrix and of the clay. Compatibilization is therefore more necessary if an incompatible polymer blend is filled with an organomodified clay in order to give a final material with good properties. In this work, a polyethylene/polyamide 6 blend filled with an organomodified clay has been compatibilized with a maleic anhydride grafted SEBS (styrene-ethylene-butylene-styrene) copolymer and a glicidylmethacrylate-ethylene copolymer. The result…

Sanidics: A new class of mesophases, displayed by highly substituted rigid-rod polyesters and polyamides

1990

Abstract The structure of rigid-chain polyesters and polyamides which possess flexible side chains consisting of methylene or 1,4,7-trioxaoctyl oxide units have been investigated by means of X-ray scattering. The X-ray studies were performed on fibres and monodomains. Additional information was gained from calorimetric, dilatometric and microscopic studies. The investigations revealed that these polymers display mesophases and that the structures of the mesophases differ from those observed for discotic and calamitic phases. They are characterized by the fact that in the ordered and disordered phases board-like molecules are stacked parallel on top of each other and that these stacks of mol…