Multinuclear Magnetic Resonance and DFT Studies of the Poly(chlorotrifluoroethylene-alt-ethyl vinyl ether) Copolymers

Are (Co)Polymers of 1,1,3,3,3-Pentafluoropropene Possible?

The copolymerization and terpolymerization of 1,1,3,3,3-pentafluoropropene (PFP) with various combinations of fluorinated and hydrogenated comonomers were investigated. The chosen fluoromonomers were vinylidene fluoride (VDF), 3,3,3-trifluoropropene (TFP), hexafluoropropene (HFP), perfluoromethylvinyl ether (PMVE), chlorotrifluoroethylene (CTFE) and tert-butyl-2-trifluoromethacrylate (MAF-TBE), while the hydrocarbon comonomers were vinylene carbonate (VCA), ethyl vinyl ether (EVE) and 3-isopropenyl-α,α-dimethylbenzyl isocyanate (m-TMI). Copolymers of PFP with non-homopolymerizable monomers (HFP, PMVE and MAF-TBE) led to quite low yields, while the introduction of VDF enabled the synthesis of poly(PFP-ter-VDF-ter-M₃) terpolymers with improved yields. PFP does not homopolymerize and delays the copolymerizations. All polymers were either amorphous fluoroelastomers or fluorothermoplastics with glass transition temperatures ranging from -56 °C to +59 °C, and they exhibited good thermal stability in air.

A New Strategy for the Synthesis of Fluorinated Polyurethane

An alternating fluorinated copolymer based on chlorotrifluoroethylene (CTFE) and butyl vinyl ether (BVE) was synthesized by RAFT/MADIX living/controlled polymerization in the presence of S-benzyl O-ethyl dithiocarbonate (BEDTC). Then, using the obtained poly(CTFE-alt-BVE) as a macro chain transfer agent (macro-CTA), a block copolymer was prepared by chain extension polymerization of vinyl acetate (VAc). After a basic methanolysis process, the poly(vinyl acetate) (PVAc) block was transferred into poly(vinyl alcohol) (PVA). Finally, a novel fluorinated polyurethane with good surface properties due to the mobility of the flexible fluorinated polymer chains linked to the network was obtained via reaction of the copolymer bearing the blocks of PVA with isophorone diisocyanate (IPDI) as a cross-linking agent.

Cobalt-Mediated Radical Copolymerization of Chlorotrifluoroethylene and Vinyl Acetate

Controlled radical copolymerization of chlorotrifluoroethylene (CTFE) and vinyl acetate (VAc) was successfully achieved in the presence of bis(acetylacetonato)cobalt(II) (Co(acac)₂) as a mediated agent and 2,2'-azo-bis-isobutyronitrile (AIBN) as initiator. Both the molar mass and the fluorinated unit content of the copolymer could be controlled, and the chain extension polymerization of the obtained fluorinated copolymer was also achieved.

Synthesis of PEVE-b-P(CTFE-alt-EVE) block copolymers by sequential cationic and radical RAFT polymerization

Block copolymers containing chlorotrifluoroethylene (CTFE) are relatively rare.

Columnar self-assembly of N,N′,N′′-trihexylbenzene-1,3,5-tricarboxamides investigated by means of NMR spectroscopy and computational methods in solution and the solid state

The columnar self-assembly resulting from units of N,N′,N′′-trihexylbenzene-1,3,5-tricarboxamide is investigated in solution and the solid state by means of NMR spectroscopy and DFT methods.

NMR spectroscopy and DFT calculations of a self-assembled arene ruthenium rectangle obtained from a combination of coordination and hydrogen bonds

Hydrogen-bonded ruthenium metalla-rectangle investigated by means of solution-phase NMR spectroscopy and DFT calculations.

Methods to prepare quaternary ammonium groups-containing alternating poly(chlorotrifluoroethylene-alt-vinyl ether) copolymers

Quaternary ammonium groups-containing alternating poly(chlorotrifluoroethylene-alt-vinyl ether) copolymers were synthesized using post-polymerization functionalization methods such as azide–alkyne cycloaddition and cyclocarbonate–amine reaction.

Radical copolymerisation of chlorotrifluoroethylene with isobutyl vinyl ether initiated by the persistent perfluoro-3-ethyl-2,4-dimethyl-3-pentyl radical

The radical copolymerisation of chlorotrifluoroethylene with isobutyl vinyl ether initiated by trifluoromethyl radicals generated by β-scission of a persistent radical is reported.

Synthesis and properties of a well-defined copolymer of chlorotrifluoroethylene and N-vinylpyrrolidone by xanthate-mediated radical copolymerization under 60Co γ-ray irradiation

RAFT/MADIX polymerization of CTFE and NVP under ⁶⁰Co γ-ray irradiation with S-benzyl O-ethyl dithiocarbonate (BEDTC).

Anhydrous proton motion study by solid state NMR spectroscopy in novel PEMFC blend membranes composed of fluorinated copolymer bearing 1,2,4-triazole functional groups and sPEEK

The proton mobility in a new family of PEMFC blend membranes containing 1,2,4-triazole groups is studied by infrared and solid state NMR spectroscopies.

Measurement and applications of long-range heteronuclear scalar couplings: recent experimental and theoretical developments

The use of long-range heteronuclear couplings, in association with (1)H-(1)H scalar couplings and NOE restraints, has acquired growing importance for the determination of the relative stereochemistry, and structural and conformational information of organic and biological molecules. However, the routine use of such couplings is hindered by the inherent difficulties in their measurement. Prior to the advancement in experimental techniques, both long-range homo- and heteronuclear scalar couplings were not easily accessible, especially for very large molecules. The development of a large number of multidimensional NMR experimental methodologies has alleviated the complications associated with the measurement of couplings of smaller strengths. Subsequent application of these methods and the utilization of determined J-couplings for structure calculations have revolutionized this area of research. Problems in organic, inorganic and biophysical chemistry have also been solved by utilizing the short- and long-range heteronuclear couplings. In this minireview, we discuss the advantages and limitations of a number of experimental techniques reported in recent times for the measurement of long-range heteronuclear couplings and a few selected applications of such couplings. This includes the study of medium- to larger-sized molecules in a variety of applications, especially in the study of hydrogen bonding in biological systems. The utilization of these couplings in conjunction with theoretical calculations to arrive at conclusions on the hyperconjugation, configurational analysis and the effect of the electronegativity of the substituents is also discussed.