Search results for "cationic polymerization"
showing 10 items of 441 documents
Enantioresolution in electrokinetic chromatography-complete filling technique using sulfated gamma-cyclodextrin. Software-free topological anticipati…
2016
Few papers have tried to predict the resolution ability of chiral selectors in capillary electrophoresis for the separation of the enantiomers of chiral compounds. In a previous work, we have used molecular information available on-line to establish enantioresolution levels of basic compounds using highly sulfated β-CD (HS-β-CD) as chiral selector in electrokinetic chromatography-complete filling technique (EKC-CFT). The present study is a continuation of this previous work, introducing some novelties. In this work, the ability of sulfated γ-cyclodextrin (S-γ-CD) as chiral selector in EKC-CFT is modelled for the first time. Thirty-three structurally unrelated cationic and neutral compounds …
Synthesis and characterization of a novel dicyanamide-bridged Co(II) 1-D coordination polymer with a N 4 -donor Schiff base ligand
2017
The synthesis, structure and magnetic properties of a novel Co(II) 1D coordination polymer, [Co(L)(µ1,5-dca)(ClO4)2·MeOH]n (1) are described. Compound 1 contains two independent cationic Co(II) chains (CoA and CoB) which are parallel to the c direction and present short π-π and C-H⋯π interactions with two neighbouring chains along the b direction, giving rise to alternating layers of chains A and B in the bc plane. Variable-temperature magnetic susceptibility measurements shows a weak antiferromagnetic coupling among the adjacent cobalt(II) centres mediated through μ1,5-dca− bridge.
Aggregation behavior of cationic nanohydrogel particles in human blood serum.
2014
For systemic siRNA delivery applications, well-defined drug carriers are required that guarantee stability for both carrier and cargo. Among various concepts progressing in market or final development, cationic nanohydrogel particles may serve as novel transport media especially designed for siRNA-in vivo experiments. In this work, the interaction of nanohydrogel particles with proteins and serum components was studied via dynamic light scattering in human blood serum as novel screening method prior to applications in vivo. The formation of larger aggregates mostly caused by charge interaction with albumin could be suppressed by nanogel loading with siRNA affording a neutral zeta potential …
Multifunctional Cationic PeptoStars as siRNA Carrier: Influence of Architecture and Histidine Modification on Knockdown Potential.
2019
RNA interference provides enormous potential for the treatment of several diseases, including cancer. Nevertheless, successful therapies based on siRNA require overcoming various challenges, such as poor pharmacokinetic characteristics of the small RNA molecule and inefficient cytosolic accumulation. In this respect, the development of functional siRNA carrier systems is a major task in biomedical research. To provide such a desired system, the synthesis of 3-arm and 6-arm PeptoStars is aimed for. The different branched polypept(o)idic architectures share a stealth-like polysarcosine corona for efficient shielding and a multifunctional polylysine core, which can be independently varied in s…
Enhancing Gene Knockdown Efficiencies by Comparing siRNA-Loaded Cationic Nanogel Particles of Different Sizes
2015
lt;pgt;In order to silence the expression levels of pathogenic genes, small interfering RNA (siRNA) requires a nano-sized carrier for its safe and stable delivery into cells. In this research highlight, we focus on well-defined cationic nanohydrogel particles developed in our group for such purposes. To investigate the nanogels’ mechanism for enhanced knockdown efficiencies, we recently synthesized two sets of particles with similar material composition and siRNA-loading characteristics, but – according to the manufacturing process – of different sizes. Within this study, 100-nm-sized nanogel particles loaded with siRNA accumulated inside the lysosomes already after 4 h and could not induce…
LC of high to moderately polar basic drugs in urine with water and detergent, and direct injection
2016
Background: Micellar LC was first proposed as a ‘green’ mode using mobile phases of water and surfactant. However, in most procedures a small amount of organic solvent is required to decrease the retention to convenient values. Results & methodology: Mixed micellar mobile phases prepared with both cationic (sodium dodecyl sulphate) and nonionic surfactant (Brij-35) modulate the retention of high to moderately polar basic drugs to practical times, eliminating the need of organic solvent. While the mobile phase is continuously recycled through the system, the stationary phase performance is maintained after repetitive injection of the samples. Discussion & conclusion: Through an exte…
Die kationische polymerisation von monomerem formaldehyd in lösung. 39. Mitt. über polyoxymethylene
1971
Die kationische Polymerisation (Fallungspolymerisation) von monomerem Formaldehyd wird in verschiedenen organischen Losungsmitteln bei −78 bis −30°C untersucht; sie ist bezuglich der Initiator- und Monomerkonzentration jeweils erster Ordnung. Die Wirksamkeit der Initiatoren fur die Polymerisation in Toluol bei −78°C nimmt in der Reihenfolge ab: SnCl4 > CH3COClO4 > HClO4 > AlBr3 > BF3 ċ O(C2H5)2 > TiCl4 > FeCl3 > SbCl5 > H2SO4 > Cl3CCOOH > HCOOH > Jod. Die Bruttoaktivierungsenergien betragen 1,0 bis 10 kcal/Mol. Die Polymerisationsgrade (Viskositatsmittel Pv) steigen meist etwa proportional mit der Monomerkonzentration und dem Umsatz an und erreichen Werte bis Pv ∼ 15000. Bei Variation des L…
Porous Coordination Polymer Based on Bipyridinium Carboxylate Linkers with High and Reversible Ammonia Uptake
2016
The zwitterionic bipyridinium carboxylate ligand 1,1'-bis(4-carboxyphenyl)-4,4'-bipyridinium (pc1) in the presence of cadmium chloride affords novel porous coordination polymers (PCPs): [Cd4(pc1)3Cl6]·CdCl4·guest (1) crystallizing in the P3̅1c space group. In the structure, [Cd4Cl6(CO2)6] building units are linked together by six pc1 ligands, leading to a 3D high-symmetrical network exhibiting hexagonal channels along the c axis. The walls of this PCP consist of cationic electron-acceptor bipyridinium units. The PCP 1 reversibly adsorbs H2O and CH3OH up to about 0.1 g/g at saturation showing the adsorption isotherms characteristic of a moderately hydrophilic sorbent. Adsorption of ammonia (…
Programmed Formation of HCN Oligomers through Organosulfur Catalysis
2021
An efficient, inexpensive, and reliable synthesis of diaminomaleonitrile (DAMN, 1) is described starting from readily available acetone cyanohydrin as the source of hydrogen cyanide (HCN). Diaminomaleonitrile (DAMN) is known to be an important intermediate in heterocyclic and medicinal chemistry as well as being a possible precursor for the origin of life's hypothesis within prebiotic chemistry. The mechanism of its formation through organosulfur catalysis has been investigated by electrospray ionization mass spectrometry (ESI-MS) using two newly synthesized cationic "marker" molecules as a tool that allows for sensitive detection. As a result, the proposed mechanism of a thiocyanate-mediat…
Synthesis, electrochemical and theoretical studies of the Au(i)-Cu(i) heterometallic clusters bearing ferrocenyl groups
2009
Treatment of the polymeric alkynyl compounds (AuC2R)n (R = Fc, C6H4Fc; Fc = ferrocenyl) with the diphosphine PPh2C6H4PPh2 gave complexes (RC2Au)PPh2C6H4PPh2(AuC2R) (1, R = Fc; 2, R = C6H4Fc) with end-capped ferrocenyl groups. The reactions of 1 or 2 with Cu(NCMe)4PF6 result in formation of the heterotrimetallic aggregates [{Au3Cu2(C2R)6}Au3(PPh2C6H4PPh2)3](PF6)2 (3, R = Fc; 4, R = C6H4Fc), which consist of the alkynyl clusters [Au3Cu2(C2R)6]−“wrapped” by the cationic [Au3(PPh2C6H4PPh2)3]3+“belt”. The novel compounds were characterized by NMR spectroscopy and ESI-MS measurements. The solid state structure of 3 is reported. Electrochemical properties of the complexes 1–4 have been studied. Th…