16837-14-2Relevant articles and documents
New formulation of old aspirin for better delivery
Kalathil, Akil A.,Kumar, Anil,Banik, Bhabatosh,Ruiter, Timothy A.,Pathak, Rakesh K.,Dhar, Shanta
, p. 140 - 143 (2016)
For better use of cyclooxygenase dependent anti-inflammatory properties and mitochondrial activities of aspirin, new hydrophobic analogues of aspirin were developed and successfully encapsulated in polymeric nanoparticles (NPs). In vivo anti-inflammatory effects of these NPs using a mouse model demonstrated unique properties of an optimized aspirin analogue to inhibit production of pro-inflammatory and enrichment of anti-inflammatory cytokines.
Oriented nanoporous lamellar organosilicates templated from topologically unsymmetrical dendritic-linear block copolymers
Magbitang, Teddie,Lee, Victor Y.,Cha, Jennifer N.,Wang, Hsiao-Lin,Chung, W. Richard,Miller, Robert D.,Dubois, Geraud,Volksen, Willi,Kim, Ho-Cheol,Hedrick, James L.
, p. 7574 - 7580 (2005)
Dendrimers between the sheets: Environmentally responsive dendritic-linear block copolymers, based on poly(ethylene oxide) and a dendron derived from 2,2′-bis(hydroxymethyl)propionic acid (see structure), were used to organize organosilicate vitrificates into nanostructured lamellar morphologies. Upon thermolysis of the template, a perforated porous lamellar structure (4 nm) between organosilicate sheets (6-9 nm) was obtained. (Chemical Equation Presented).
Synthesis, Micellization, and Surface Activity of Novel Linear-Dendritic Carboxylate Surfactants
Lou, Yuning,Dong, Yajuan,Wang, Xiaoyong,Gong, Feirong,Zhao, Min,Rong, Zongming
, p. 3 - 13 (2021)
Two generations of novel linear-dendritic carboxylate surfactants C18-G1-(COONa)2 and C18-G2-(COONa)4 have been synthesized by the divergent method and their structures are characterized by 1H Nuclear Magnetic Resonance and Infrared analysis. The electrical conductivity measurement is used to measure the Krafft temperatures of C18-G1-(COONa)2 and C18-G2-(COONa)4, which are much smaller than those of the corresponding conventional surfactant sodium stearate. The markedly enhanced solubility of two linear-dendritic surfactants is ascribed to the high hydrophilicity of surfactant headgroups induced by the carboxylate and ester groups. The critical micelle concentration (CMC) values obtained from both the electrical conductivity and surface tension measurements indicate that the micellizations of linear-dendritic surfactants become favorable with the increase in the number of the surfactant headgroup. However, the surface activity parameters including the surface tension at the CMC, maximum surface excess, and minimum surface area reveal that C18-G1-(COONa)2 exhibits greater efficiency in absorbing at the air/water interface compared to C18-G2-(COONa)4, owing to their different steric repulsions of the surfactant headgroups. In addition, C18-G1-(COONa)2 and C18-G2-(COONa)4 have higher emulsifying ability than the conventional surfactants sodium stearate and sodium octadecyl sulfate.
Catalytically active hybrid polyurethane with tetraaniline pendant groups: Synthesis, properties and self assembly
Arukula, Ravi,Rao, Chepuri R.K.,Narayan, Ramanuj,Sreedhar
, p. 334 - 344 (2015)
For the first time we report a novel hybrid polyurethane synthesized from tetraaniline-diol (TAni-(OH)2) and hexamethylene diisocyanate (HMDI) with pendant tetraaniline units on the back bone. The striking property of this unprecedented polyurethane is its electrochemical sensing of ascorbic acid and self assembly into core-shell type microstructures (microcapsules) in presence of aqueous acetic acid/n-octane interface. These microcapsules exhibited a wide range of pH responses in their absorption spectrum. The synthesized polyurethane containing pendant tetraaniline units showed good surface conductivity to the tune of 3.4 × 10-4 S/cm. The electrochemical investigation showed two single electron oxidations and two single electron reductions reversibly. We also investigated electrochemical sensing details of carbon paste electrode (CPE) fabricated with conducting polyurethane (TANI-PU) as ascorbic acid sensor (vitamin C, AA) in 0.2 M and pH 7 phosphate buffer solution. The fabricated electrode is useful in sensing as low as 1 mM of ascorbic acid. Self-assembly property was probed by optical and TEM studies which established the core-shell structure of the assembled species. The self assembled microcapsules exhibited pH dependent doping and dedoping processes as established by UV-Vis study.
Molecular brushes with extreme grafted side chain densities
Bak, Jae Min,Jha, Gourishanker,Ahn, Eungjin,Jung, Seo-Hyun,Jeong, Han Mo,Kim, Byeong-Su,Lee, Hyung-Il
, p. 3462 - 3468 (2012)
A series of densely grafted poly(n-butyl acrylate) (PBA) molecular brushes with four different grafting densities were synthesized by the "grafting-from" approach using atom transfer radical polymerization (ATRP). A novel monomer, isopropylidene-2,2-Bis(methoxy)propionic hydroxyethylmethacrylate (IMPHMA), was synthesized and copolymerized with methyl methacrylate (MMA) under different monomer feed ratios to yield a series of linear poly(methyl methacrylate-stat-IMAPA), [PMMA-s-(PIMPHMA)]. The resulting copolymers were deprotected and transformed to macroinitiators, [PMMA-s-(PHEMA-IMPHMA-Br)]. n-Butyl acrylate (BA) was grafted from these macroinitiators to yield a series of molecular brushes, [PMMA-s-{(PIMPHMA)-g- PBA}], with various side chain lengths. Molecular brushes were characterized by gel permeation chromatography (GPC) and 1H NMR. PBA side chains were cleaved by acid hydrolysis, and the resulting linear PBA polymers were characterized by GPC to study initiation efficiency during the synthesis of molecular brushes. The initiation efficiency increased with polymerization time and decreased with macroinitiators that had more initiation sites. Atomic force microscopy (AFM) measurements demonstrated the characteristic molecular structure by resolving individual brush molecules.
"Click" synthesis of intrinsically hydrophilic dendrons and dendrimers containing metal binding moieties at each branching unit
Wang, Lili,Kiemle, David J.,Boyle, Connor J.,Connors, Eoghan L.,Gitsov, Ivan
, p. 2199 - 2213 (2014)
A new family of water-soluble triazole dendrimers composed of tri(ethylene glycol) (TrEG) and bis(methylol)propionic acid (bis-MPA) was created through Cu(I)-catalyzed alkyne-azide cycloaddition (CuAAC) between specifically designed complementary building blocks. Dendrimers up to generation three were synthesized by CuAAC to a trifunctional core with yields ranging from 72% for generation one, through 67% for generation two, and 64% for third generation dendrimer. The two triazole rings at each bis-MPA branching site could serve as efficient chelating pockets for some VIIIA group elements. As proof-of-principle, the [PdCl2(PhCN)2] coordination chemistry of these hydrophilic dendritic ligands was studied by 1H NMR, dynamic light scattering, transmission electron microscopy, and DFT calculations. The results showed that the complexation is completed within 5 min. The novel hydrophilic dendritic Pd complexes were able to catalyze Suzuki-Miyaura coupling reactions in water within 3 h at 100 °C, at 60 °C, and even at 50 °C with practically quantitative conversion.
Formation kinetics and scaling of "defect-free" hyperbranched polystyrene chains with uniform subchains prepared from seesaw-type macromonomers
Li, Lianwei,He, Chen,He, Weidong,Wu, Chi
, p. 8195 - 8206 (2011)
Using a facile approach, we successfully made large "defect-free" hyperbranched polystyrene (PSt) chains with uniform subchains between two branching points from the interchain "clicking" of a seesaw-type linear macromonomer [azide～～～alkyne～～～azide] prepared by ATRP with a following conversion of two bromine-ends into two azide-ends, where ～～～ denotes a PSt chain (1.65-31.0 kg/mol). The "click" reaction kinetics monitored by a combination of size exclusion chromatography (SEC) and laser light scattering (LLS) reveals that the degree of self-polycondensation (DP) is related to the reaction time (t) as ln(DP+ 1)/2 = ([A]0kAB,0)/β arctan(βt), where [A]0 and kAB,0 are the initial alkyne concentration and the initial reaction rate between the azide and alkyne groups, respectively; β is a constant and its reciprocal (1/β) represents the time at which k AB = kAB,0/2. The results reveal that 1/β is scaled to the macromonomer's molar concentration ([C]) and molar mass (M) as 1/β ～ [C]-0.35M0.55, indicating that 1/β is governed by the interchain distance and diffusion, respectively. Each hyperbranched sample can be further fractionated into a set of narrowly distributed "defect-free" hyperbranched chains with different molar masses by precipitation. The LLS results show, for the first time, that the root-mean-square radius of gyration (〈Rg〉) and hydrodynamic radius (〈Rh〉) of "defect-free" hyperbranched polystyrenes in toluene at 25 °C are scaled to the weight-average molar mass (Mw) as 〈Rg〉 = 5.53 × 10 -2Mw0.464 and 〈Rh〉 = 2.95 × 10-2Mw0.489, respectively, where the exponents are smaller than the predicted 1/2.
Accelerated Chemoselective Reactions to Sequence-Controlled Heterolayered Dendrimers
García-Gallego, Sandra,Andrén, Oliver C. J.,Malkoch, Michael
, p. 1501 - 1509 (2020)
Chemoselective reactions are a highly desirable approach to generate well-defined functional macromolecules. Their extraordinary efficiency and selectivity enable the development of flawless structures, such as dendrimers, with unprecedented structure-to-property capacity but with typically tedious synthetic protocols. Here we demonstrate the potency of chemoselective reactions to accomplish sequence-controlled heterolayered dendrimers. An accurate accelerated design of bis-MPA monomers with orthogonally complementary moieties and a wisely selected chemical toolbox generated highly complex monodisperse dendrimers through simplified protocols. The versatility of the strategy was proved by obtaining different dendritic families with different properties after altering the order of addition of the monomers. Moreover, we evaluated the feasibility of the one-pot approach toward these heterolayered dendrimers as proof-of-concept.
TWO-WAY MAGNETIC RESONANCE TUNING NANOPROBE ENHANCED SUBTRACTION IMAGING
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Paragraph 0039; 0145, (2021/06/26)
The present invention provides a nanocarrier having an interior and an exterior, the nanocarrier comprising: a plurality of amphiphilic compounds that self-assemble to form the nanocarrier; and a first magnetic resonance imaging (MRI) contrast agent and a
Synthesis of Heterofunctional Polyester Dendrimers with Internal and External Functionalities as Versatile Multipurpose Platforms
Garciá-Gallego, Sandra,Stenstr?m, Patrik,Mesa-Antunez, Pablo,Zhang, Yuning,Malkoch, Michael
, p. 4273 - 4279 (2020/11/09)
Heterofunctional dendrimers with internal and external representations of functionalities are considered as the ultimate dendritic frameworks. This is reflected by their unprecedented scaffolding, such as precise control over the structure, molecular weig
