Continuous Synthesis of Main-Chain-type Fluorinated Graft Copolymers via Successive Flow START Polymerization and Cu(0)-Mediated RDRP

Fluorinated polymers are receiving more and more attention worldwide due to their unique chemical properties,and modified fluorinated polymers with different topologies are persued for enriching and enhancing their performance in a variety of application fields.In this work,main-chain-type semifluorinated graft copolymers are produced steadily in continuous tube reactors via photocontrolled step transferaddition and radical-termination(START)polymerization and Cu(0)-mediated reversible deactivation radical polymerization(Cu(0)-RDRP)at room temperature for the first time.Specifically,semifluorinated alternating copolymer(AB)n B is prepared by START polymerization of 1,6-diiodoperfluorohexane(A)and 1,7-octadiene(B)in the first quartz pipeline under irradiation with purple LED light at 20℃.The(AB)nB with periodic C―I bonds is then flowed into the second copper pipeline directly and acts as the macroinitiators for Cu(0)-RDRP of methyl acrylate(MA)to obtain corresponding graft copolymer(AB)n B-g-PMA.This work provides a new strategy for continuous synthesis of fluorinated graft copolymer materials.

Theoretical studies on the complexation of Eu(Ⅲ) and Am(Ⅲ) with HDEHP： structure, bonding nature and stability

Separation of trivalent lanthanides （Ln（Ⅲ）） and actinides （An（Ⅲ）） is a key issue in the advanced spent nuclear fuel repro- cessing. In the well-known trivalent actinide lanthanide separation by phosphorus reagent extraction from aqueous komplexes （TALSPEAK） process, the organophosphorus ligand HDEHP （di-（2-ethylhexyl） phosphoric acid） has been used as an efficient reagent for the partitioning of Ln（Ⅲ） from An（Ⅲ） with the combination of a holdback reagent in aqueous lactate buffer solu- tion. In this work, the structural and electronic properties of Eu3＋ and Am3＋ complexes with HDEHP in nitric acid solution have been systematically explored by using scalar-relativistic density functional theory （DFT）. It was found that HDEHP can coordinate with M（Ⅲ） （M=Eu, Am） cations in the form of hydrogen-bonded dimers HL2 （L=DEHP）, and the metal ions pre- fer to coordinate with the phosphoryl oxygen atom of the ligand. For all the extraction complexes, the metal-ligand bonds are mainly ionic in nature. Although Eu（Ⅲ） complexes have higher interaction energies, the HL2- dimer shows comparable affini- ty for Eu（Ⅲ） and Am（Ⅲ） according to thermodynamic analysis, nonahydrate. It is expected that this work could provide insightful HDEHP at the molecular level. which may be attributed to the higher stabilities of Eu（Ⅲ） information on the complexation of An（Ⅲ） and Ln（Ⅲ） with

A combined DFT and molecular dynamics study of U(Ⅵ)/calcite interaction in aqueous solution

Here we present a combined DFF and molecular dynamics study of uranyl （U（VI）） interaction mecha- nisms with the calcite （104） surface in aqueous solution. The roles of three anion ligands （CO2 , HCO3, OH ） and solvation effect in U（VI） interaction with calcite have been evaluated. According to our calculations, water adsorbed on the calcite （104） surface prefers to exist in molecular state rather than dis- sociative state. Energy analysis indicate that the positively charged uranyl species prefers to form surface complexes on the surface, while neutral uranyl species may bind with the surface via both surface complexing and ion exchange reactions of U（VI） → Ca（II）. In contrast, the negatively charged uranyl species prefer to interact with the surface via ion exchange reactions of U（VI）→ Ca（II）, and the one with UO2（CO3）2（H2O）^2- as the reactant becomes the most favorable one in energy. We also found that uranyl adsorption increases the hydrophilicability of the （104） surface to different extents, where the UO2（CO3）3Ca2 species contributes to the largest degree of energy changes （ 53 kcal/mol）. Our calcula- tions proved that the （104） surface also has the ability to immobilize U（VI） via either surface complexing or ion exchange mechanisms under different pH values.

Design criteria for tetradentate phenanthroline-derived heterocyclic ligands to separate Am(Ⅲ) from Eu(Ⅲ)

To design novel phenanthroline-derived soft ligands for selectively separating minor actinides from lanthanides, four tetradentate phenanthroline-derived heterocyclic ligands(BTPhen, BPyPhen, BPzPhen, and BBizPhen) were constructed and their complexation behaviors with Am(ⅡI) and Eu(ⅡI) were systematically investigated by density functional theory(DFT) coupled with relativistic small-core pseudopotential. In all the 1:1-type species, the metal ion is in the center of the cavity and coordinates with two nitrogen atoms(N1 and N1′) of the phenanthroline skeleton and the other two nitrogen atoms(N2 and N2′) of the auxiliary groups. The bond lengths of Am–N are comparable to or even shorter than those of Eu–N bonds because the ionic radii of Am(ⅡI) are larger than those of Eu(ⅡI). Additionally, the negative ΔΔGAm/Eu value for the reaction of [M(H2O)4-(NO3)3] + L → ML(NO3)3 + 4H2 O indicates that the complexation reaction of Am(ⅡI) is more energetically favorable than that of Eu(ⅡI); this can be considered as an important design criterion to screen phenanthroline-derived ligands for MA(ⅡI) extraction. According to this criterion, the selectivity of tetradentate phenanthroline-derived ligands for separating Am(ⅡI) over Eu(ⅡI) follows the order of BTPhen > BBizPhen > BPyPhen > BPzPhen.