Search results for " polymerization"

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.

Über den angriff des carboniumions am monomeren styrol bei der kationischen copolymerisation von trioxane und styrol. 19. Mitt. über polyoxymethylene

1962

Bei der Saure-katalysierten Hydrolyse von kationisch dargestellten Copolymeren aus Trioxan und Styrol entsteht 4-Phenyl-1,3-Dioxan. Das last sich nur so erklaren, das in Analogie zur radikalischen und zur anionischen Polymerisation der Angriff des Carboniumions ebenfalls am β-Kohlenstoffatom des Styrols erfolgt. Formation of 4-phenyl-1,3-dioxan occurs during the acid catalyzed hydrolysis of cationically produced copolymers of trioxane and styrene. The only possible explanation involves an attack of the carboniumion at the β-carbonatom of styrene analogous to the radical and anionic polymerization.

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…

Utilization of dense carbon dioxide as an inert solvent for chemical syntheses

2010

Stable Carbanions by Quantitative Metalation of Cationically Obtained Diphenylvinyl and Diphenylmethoxy Compounds:  New Initiators for Living Anionic…

1997

2-(1-Aryliminoethyl)-9-arylimino-5,6,7,8- tetrahydrocycloheptapyridyl iron(II) dichloride: synthesis, characterization, and the highly active and tun…

2014

A series of 2-(1-arylimino)ethyl-9-arylimino-5,6,7,8-tetrahydrocycloheptapyridine derivatives was synthesized and fully characterized, and thereafter reacted with iron dichloride to form their corresponding iron(II) complexes. The single crystals of representative organic and iron complex compounds were obtained and analyzed by the X-ray diffraction analysis, indicating the distorted bipyramidal geometry around the iron core. Moreover, DFT calculations were performed on selected species to determine their structural features. On treatment with either MAO or MMAO, all iron complex pre-catalysts showed high activities (up to 1.56 × 10(7) gPE mol(-1)(Fe) h(-1)) toward ethylene polymerization. …