Search results for "cationic polymer"

New approach for synthesis of poly(ethylglyoxylate) using Maghnite-H + , an Algerian proton exchanged montmorillonite clay, as an eco-catalyst

2017

International audience; In this works, we have explored a new method for a green synthesis of poly(ethylglyoxylate) (PEtG). This method consists on using a montmorillonite clay called Maghnite-H+ as an eco-catalyst to replace triethylamine which is toxic. Cationic polymerization experiments are performed in bulk conditions at three temperatures (-40 degrees C, 25 degrees C, 80 degrees C) and in THF solutions at room temperature (25 degrees C). At 25 degrees C, an optimum ratio of 5 wt% of catalyst leads to molar masses up to 22000 g/mol in THF solutions. Polymerizations in bulk conditions lead to slightly lower masses than experiments conducted in THF solutions. However, bulk polymerization…

Modelling Photoionisations in Tautomeric DNA Nucleobase Derivatives 7H-Adenine and 7H-Guanine: Ultrafast Decay and Photostability

2021

The study of radiation effects in DNA is a multidisciplinary endeavour, connecting the physical, chemical and biological sciences. Despite being mostly filtered by the ozone layer, sunlight radiation is still expected to (photo)ionise DNA in sizeable yields, triggering an electron removal process and the formation of potentially reactive cationic species. In this manuscript, photoionisation decay channels of important DNA tautomeric derivatives, 7H-adenine and 7H-guanine, are characterised with accurate CASSCF/XMS-CASPT2 theoretical methods. These simulation techniques place the onset of ionisation for 7H-adenine and 7H-guanine on average at 8.98 and 8.43 eV, in line with recorded experimen…

Comparative cytotoxic study of silica materials functionalised with essential oil components in HepG2 cells

2020

[EN] This work evaluated the cytotoxic effect of different EOCs-functionalised silica particle types. The in vitro toxicity of eugenol and vanillin-immobilised SAS, MCM-41 microparticles and MCM-41 nanoparticles was evaluated on HepG2 cells, and compared to free EOCs and pristine materials. The results revealed that free essential oil components and bare silica had a mild cytotoxic effect on HepG2 cells. However, the comparative study showed that free eugenol and vanillin had a milder cytotoxic effect than the equivalent concentrations of immobilised components on the different silica particles, while differences in cell viability between the bare and functionalised particles relied on the …

Novel cationic polyaspartamide with covalently linked carboxypropyl-trimethyl ammonium chloride as a candidate vector for gene delivery

2006

Abstract The non-viral gene vector properties of a protein-like polymer, the α,β-poly(N-2-hydroxyethyl)- d , l -aspartamide (PHEA) were investigated after its derivatization with 3-(carboxypropyl)trimethyl-ammonium chloride (CPTA) as molecule bearing cationic groups, in order to obtain stable polycations able to condense DNA. PHEA was firstly functionalized with hydrazide pendant groups by reaction with hydrazine monohydrate (HYD), obtaining the polyhydrazide α,β-poly(N-2-hydroxyethyl/carbazate)- d , l -aspartamide (PHEA–HYD). In this paper we reported that polymer functionalization degree can be easily modulated by varying reaction conditions, so allowing us to produce two PHEA derivatives…

Hydrogen-bonded dimers of a thiacalixarene substituted by carbamoylmethylphosphineoxide groups at the wide rim.

2006

A thiacalix[4]arene derivative bearing four carbamoylmethylphosphineoxide groups at the wide rim forms hydrogen-bonded, dimeric capsules with S8 symmetry in the crystalline state and in apolar solvents, where the inclusion of cationic guests could be proved by 1H NMR and ESI mass spectra.

ChemInform Abstract: Transition Metal Derivatives of Low Oxidation State Phosphorus Oxoacids: Synthetic Pathways and Structural Studies

2010

Abstract A general synthetic approach intended to rationalize the solution preparative chemistry of transition metal phosphites and hypophosphites is presented. As previously shown for other derivatives containing also tetrahedral or pseudotetrahedral oxoanions, the hydrolytic processes affecting the cationic moieties play a determinant role on the very nature of the final solid. In fact, despite the limited number of donor atoms in the anions, the crystal chemistry of these compounds is quite intricate because of both the variety of possible cationic aggregates and the many ways to interconnect them through pseudotetrahedral anionic groups.

Some new examples of cationic polymerization

1986

Preparation, proprietes et polymerisation cationique de cis et trans-methoxyvinylchlorure. Le polymere trans est surtout threodiisotactique. Copolymerisation du cis avec le trans ou le styrene ou le dioxolanene-1,3. Polymerisation de la phenyl-2 oxazoline et de la conidine

1984

Alkaline hydrolyses of anionic phenyl esters such as 4-acetoxy-3-nitrobenzoic acid and 4-butyryloxy-3-nitrobenzoic acid were examined in the presence of cationic and polymeric liposomes, liposomes of low molecular weight compounds, and micelles. All the additives accelerate the reaction due to the hydrophobic interaction between substrates and additives and the electrostatic interaction both between substrates and additives and between OH− and additives. In the Arrhenius plots of the reactions catalyzed by the liposomes, discontinuous regions were observed due to the phase transition of liposomes from the gel state to the liquid crystal state. Activation parameters ΔH≠, ΔS≠ and ΔV≠ for thes…

Rapid Access to Polyfunctional Lipids with Complex Architecture via Oxyanionic Ring-Opening Polymerization

2011

Polymer-coated liposomes, particularly poly(ethylene glycol) (PEG)-substituted liposomes, have emerged as long-circulating carrier systems for drug delivery and diagnostic purposes. A rapid synthesis of three different types of multifunctional lipids with structurally diverse hydrophilic, polyether-based architectures via one- or two-pot approaches is described. Architectural variation is achieved by the combination of different oxyanionic polymerization strategies and various glycidyl ether building units. Branched polyglycerol lipids have been prepared via cholesterol- or 1,2-bis-n-alkyl glyceryl ether-initiated, oxyanionic ring-opening polymerization (ROP) of protected glycidyl ethers an…

Novel mixed-valence Cu compounds formed by Cu(II) dimers with double oximato bridges: in situ formation of anionic layer [Cu2(SCN)3]n(n-).

2013

Two new N3O donor ketoxime Schiff bases (HL(1) and HL(2)) have been synthesized by condensing N,N-dimethylethylenediamine with diacetylmonoxime and benzilmonoxime, respectively in a 1:1 ratio. Reaction of Cu(ClO4)2·6H2O with HL(1) resulted in a discrete oximato-bridged dinuclear Cu(II) complex [Cu2(L(1))2(H2O)2](ClO4)2 (1). The same reaction in presence of NaSCN affords the complex {[Cu(II)2(L(1))2][Cu(I)4(μ(1,3)-SCN)4(μ(1,1,3)-SCN)2]}n (2), where partial Cu(II)→Cu(I) reduction is observed. In 2, arrays of [Cu(II)2(L(1))2](2+) cationic units are inserted in between 2D {[Cu(I)4(SCN)6](2-)}n layers and connected via μ(1,1,3)-SCN(-) links, thus forming a 3D network. On the other hand, reaction…