- Organic-inorganic hybrid materials designed by controlled radical polymerization and mediated using commercial dual functional organophosphorous coupling agents
-
Hybrid materials that are composed of a polymeric material interfaced with an inorganic, metal oxide material have been a rapidly expanding research area in the last few decades. However, interfacial regions remain an important area of focus, and as such hybrid materials do not always possess a very robust or stable interface. Tailor-made interfacial molecules have been successfully reported but material scientists wishing to develop composite interfacial materials would favorably use commercial solutions. Our study shows how we can leverage a commercially available organophosphonic acid group that is coupled with a 2-bromo isobutyrate initiator for surface initiated atom transfer radical polymerization (SI-ATRP) for use as a strong interfacial molecule. We illustrate this mechanism with both nanoparticles of titania and flat titania substrates used as the grafting support and polymerization anchoring points. We demonstrate that the size of the organophosphonic acid initiator, specifically the carbon spacer between the reactive groups, controls the stability of the molecule. The actual covalent linkage between the phosphonic acid group and the titania surface while also leaving the ATRP initiating group able to start the polymerization, is confirmed via31P solid state NMR spectroscopy, liquid 1H NMR spectroscopy XPS, DLS and SEM.
- Cao, Edgar,Prouzet, Eric,Hroguez, Valrie
-
-
Read Online
- Inimer graft-copolymerized poly(vinylidene fluoride) for the preparation of arborescent copolymers and surface-active copolymer membranes
-
A novel graft copolymer was synthesized via graft copolymerization of an inimer, 2-(2-bromoisobutyryloxy)ethyl acrylate (BIEA), with ozone-pretreated poly(vinylidene fluoride) (PVDF) (the PVDF-g-PBIEA copolymer). Porous membranes could be fabricated from the copolymer solution by phase inversion. The BIEA polymer (PBIEA) side chains allowed the initiation of atom transfer radical polymerization (ATRP) of functional monomers on the copolymer and the membrane surface. An arborescent copolymer was prepared via ATRP of sodium 4-styrenesulfonate (NaSS) initiated from the PVDF-g-PBIEA copolymer side chains (PVDF-g-PBIEA-ar-NaPSS copolymer). In comparison with the PVDF-g-PBIEA-ar-NaPSS copolymer membrane cast in water by phase inversion, the copolymer membrane cast in 1 M aqueous NaCl solution had enriched NaPSS side chains on the surface and larger pore size. The PVDF-g-PBIEA-ar-PPEGMA membrane was prepared via the surface-initiated ATRP of poly(ethylene glycol) methacrylate (PEGMA) on the porous PVDF-g-PBIEA membrane. Protein adsorption studies indicated that the PVDF-g-PBIEA-ar-PPEGMA membrane exhibited substantially improved antifouling properties. Thus, the PVDF-g-PBIEA membranes with the active ATRP inimer repeat units on the surface offers opportunities for the functionalization of membranes via surface molecular design.
- Zhai, Guangqun,Kang,Neoh
-
-
Read Online
- Reaction of Lithium Acylate α-Carbanions with Carbon Tetrabromide
-
Lithium acylate α-carbanions generated by metalation of acetic, butanoic, and 2-methylpropanoic acids with lithium diisopropylamide in THF under argon reacted with carbon tetrabromide at 20-25°C (2 h) to produce butanedioic acid or its 2,3-diethyl and 2,2,3,3-tetramethyl derivatives, as well as the corresponding 2-bromocarboxylic acids and bromoform. The effect of the halogen nature in carbon tetrahalide (CCl4, CBr4) on the reaction selectivity is discussed.
- Zorin,Zaynashev,Zorin
-
p. 1527 - 1531
(2019/12/28)
-
- Method for synthesizing ethyl alpha-bromoisobutyrate
-
The invention discloses a method for synthesizing ethyl alpha-bromoisobutyrate. The ethyl alpha-bromoisobutyrate is synthesized by using isobutyric acid as a starting material through bromination andesterification. N-bromosuccinimide or N-bromophthalimide is used as a bromination reagent in the bromination, so as to improve the utilization of bromine atoms and improve the safety of the process; the esterification is catalyzed by a double catalytic system, and the zinc powder added and the trace bromine of the bromination form ZnBr2 as a catalyst for the esterification, so the scheme has fewerside reactions, low corrosion, high selectivity and good product appearance quality.
- -
-
Paragraph 0043-0046; 0050-0053; 0057-0060
(2019/01/08)
-
- Reactions of α-carbanions of lithium acylates with N,N-diethyl-N-chloro- and N,N-diethyl-N-bromoamines
-
The interaction of α-carbanions of lithium acylates (prepared via metalation of acetic, butyric, or isobutyric acid with lithium diisopropylamide in tetrahydrofuran under argon atmosphere) with N,N-diethyl-N-chloro- or N,N-diethyl-N-bromoamine has resulte
- Zorin,Zainashev,Zorin
-
p. 2469 - 2472
(2016/12/24)
-
- Utilising 14C-radiolabelled atom transfer radical polymerisation initiators
-
14C-radio-initiated atom transfer radical polymerisations allow direct monitoring of the fate of initiating species.
- Long, Mark,Thornthwaite, David W.,Rogers, Suzanne H.,Bonzi, Gwenaelle,Livens, Francis R.,Rannard, Steve P.
-
supporting information; experimental part
p. 6406 - 6408
(2010/03/04)
-
- Chromium-mediated aldol and homoaldol reactions on solid support directed towards an iterative polyol strategy
-
Chromium-Reformatsky and chromium-homoaldol reactions run under neutral and mild reaction conditions. They are highly chemoselective, tolerant towards most common functional groups, and are not prone to retroaldol reactions. Initial studies directed to transfer these homogeneous chromium-mediated solution-phase reactions to solid phase are presented. The main objective was to develop a methodology to aid a combinatorial iterative strategy to polyols (polyketides) on solid phase. A general reactivity problem was observed with polystyrene based resins compared to the solution-phase reactions, independent if the electrophilic (aldehyde) or nucleophilic (bromide) end of the polyol chain was supported to the resin. A complicated penetration, or loss of the polar solvent environment after penetration into the resin, might be responsible for the reduced reactivity. Application of either a soluble polystyrene resin or a polystyrene resin with a polar polyethylene glycol tether resulted in improved yields.
- Wessjohann, Ludger A.,Wild, Harry,Schrekker, Henri S.
-
p. 9073 - 9078
(2007/10/03)
-
- Design and synthesis of potent thiol-based inhibitors of endothelin converting enzyme-1
-
Through directed screening of compounds prepared as metalloprotease inhibitors a compound, CGS 30084, that had potent endothelin converting enzyme-1 (ECE-1) in vitro inhibitory activity (IC50=77nM) was identified. Herein we report the synthesis and optimization of ECE-1 inhibitory activity of additional analogues from this lead. Compound 3c, the thioacetate methyl ester derivative of compound 4c, was found to be a long acting inhibitor of ECE-1 activity in rats after oral administration. (C) 2000 Elsevier Science Ltd.
- Fink, Cynthia A.,Moskal, Michael,Firooznia, Fariborz,Hoyer, Denton,Symonsbergen, David,Wei, Dongchu,Qiao, Ying,Savage, Paula,Beil, Michael E.,Trapani, Angelo J.,Jeng, Arco Y.
-
p. 2037 - 2039
(2007/10/03)
-
- A simple and efficient method of preparing α-bromo carboxylic acids
-
A new and convenient method for α-bromination of aliphatic carboxylic acids is reported. Heating carboxylic acids for 16 hours at 85 °C in trifluoroacetic acid with 1.5 equivalents of N-bromosuccinimide and a catalytic amount of concentrated H2SO4 leads to good yields of the respective α-bromocarboxylic acids.
- Zhang, Lian Hao,Duan, Jianxin,Xu, Yuelian,Dolbier Jr., William R.
-
p. 9621 - 9622
(2007/10/03)
-
- Preparation of optically active α-(hydroxyphenoxy)alkanecarboxylic acids and derivatives thereof
-
Optically active α-(hydroxyphenoxy)-alkanecarboxylic acids or derivatives thereof, for example D-2-(4-hydroxyphenoxy)propionic acid or lower alkyl ester thereof, are prepared by (a) saponifying an alkyl ester of an optically active α-halogeno-alkanecarboxylic acid, in an alcoholic solvent medium, by reacting same with an aqueous solution of an alkali metal hydroxide, thereby providing a solution of an alkali metal salt of an optically active α-halogeno-alkanecarboxylic acid, (b) next reacting the step (a) solution thus provided with a dihydroxybenzene or salt thereof, in the presence of an alkali metal hydroxide and in an alcoholic solvent medium, and thence (c) recovering the optically active α-(hydroxyphenoxy)-alkanecarboxylic acid or derivative thereof from the medium of reaction.
- -
-
-
- Azido acids in a novel method of solid-phase peptide synthesis
-
Azido acids were produced from α-branched acids by α-bromination with NBS followed by substitution with sodium azide and the products were used in a novel method of solid-phase synthesis. The azido acids were transformed into the highly activated acid chlorides and used synthesis of extremely hindered peptides containing up to four successive diphenyl glycine or Aib residues. By reaction of the genetically encoded amino acids with TfN3 and then SOCl2 they were transformed into α-azido acid chlorides used in solid-phase peptide synthesis without racemization.
- Meldal, Morten,Juliano, Maria A.,Jansson, Anita M.
-
p. 2531 - 2534
(2007/10/03)
-
- Pyridylthio-acylanilide herbicides
-
Novel herbicidally active pyridylthio-acylanilides of the formula STR1 in which R1, R2 and R3, independently of one another, represent hydrogen, halogen, cyano or trifluoromethyl or alkyl, alkoxy and alkylthio having 1 to 4 carbon atoms in each case, R4 represents halogen, methyl or methoxy, n represents a number 0, 1 or 2, z represents the group (Ia) STR2 or the group (Ib) STR3 where X represents oxygen, sulphur, an N--R10 or N--O--R11 group, or X and Rg tpgether represent the STR4 radical, and the other radicals can have various meanings. Intermediates of the formulae STR5 are also new.
- -
-
-