27780-89-8Relevant academic research and scientific papers
Supramolecular gold nanoparticles for the redox recognition of oxoanions: Syntheses, titrations, stereoelectronic effects, and selectivityt
Labande, Agnes,Ruiz, Jaime,Astruc, Didier
, p. 1782 - 1789 (2002)
Stable, CH2Cl2-soluble mixed dodecanethiol/(amidoferrocenyl)alkanethiol (AFAT) gold colloids were synthesized by ligand substitution reactions from Brust's dodecanethiol gold colloids and the AFAT ligands to study the recognition and titration of oxoanions. Gold colloids were obtained with various chain lengths (C11 and C6 chains) of the AFAT ligand and different proportions of AFAT ligands in the colloids. Modification of the amidoferrocenyl structure [replacement of the free C5H5 ferrocene ring by C5Me5 (CP*) or C5H4COCH3] has been achieved to investigate the stereoelectronic effects on the recognition. The cyclic voltammetry of these colloids in CH2Cl2 on Pt electrode shows a reversible FeII/IIII wave with some adsorption. With AFAT ligands, a new, less electrochemically reversible wave (with some adsorption) at a potential 220 ± 20 mV less positive than that of the initial wave appears upon titration of [n-Bu4N][H2PO4], and the initial wave completely disappears after addition of 1 equiv of anion, which allows its titration. The potential shift does not depend on the AFAT proportion nor on its chain length but is reduced with Cp* and enhanced with C5H4COCH3, showing the key role of the hydrogen bonding between the -NH- amido group and a terminal oxygen atom of the oxoanions. According to the Echegoyen-Kaifer model, the potential shift leads to the ratio K(+)IK(0) of apparent association constants. In the presence of both [n-Bu4N][HSO4 and [n-Bu4N]Cl, a shift of the initial wave (rather than its replacement) allows an easy titration, ideally with 20-Fc. Upon addition of [n-Bu4N][HSO4] alone, a weak wave shift (30 mV) of the colloids is also observed, allowing the titration of the HSO4- anion by the colloids containing a low percentage of AFAT ligand. The EchegoyenKaifer model provides access to the apparent association constant K(+) in this case for which the interaction between the anion and the neutral form of the host is not significant. With the C5H4COCH3 modification of the amidoferrocenyl branch, a new wave appears at a potential 70 mV more positive than the initial wave, signifying a stronger interaction with this modified ligand than with the parent AFAT ligand. These colloids favorably compare with ferrocenyl dendrimers in terms of rapid synthesis and selectivity of H2PO4- over HSO4- and with gold surfaces for the recognition of HSO4-.
Preparation of anthryl group-tagged helical poly(γ-benzyl L-glutamate) self-assembled film on gold surface and its interaction with DNA
Niwa, Masazo,Morikawa, Masa-Aki,Nabeta, Tomohiro,Higashi, Nobuyuki
, p. 2769 - 2775 (2002)
A novel poly(γ-benzyl-L-glutamate) (PBLG, 1), which has an anthryl group at the C-terminus of PBLG segment, has been synthesized, and its immobilization onto gold surface based on a specific interhelix interaction and DNA binding property at a self-assembled monolayer surface have been studied. A PBLG carrying a S-S bond at the C-terminus, 3, formed self-assembled monolayers on a gold surface. Within a resulting monolayer of 3, helical rods of the PBLG segment were oriented in the antiparallel manner, allowing an attractive interaction between helix macrodipoles. When a helix-breaking solvent such as DMSO was added to the solution, about a half amount of the adsorbate was released from the monolayer, followed by weakening the interhelix interaction, and a porous monolayer including molecular cavities was formed. Such a cavity size should fit the occupied volume of the helices present in the original assembly. Guest helices of 1 and 2, which has a similar molecular structure to that of I except for the lack of the anthryl moiety, could interact with the host porous monolayer of 1 on gold substrates. The binding properties of DNA onto 1, 2, and 3 mixed monolayers, in which anthryl groups must be located at the monolayer surface, were examined by means of quartz crystal microbalance and X-ray photoelectron spectroscopy. The results indicated that DNA bound to the PBLG mixed monolayers when the anthryl groups at the monolayer surface were in an optimized distribution.
Inkless microcontact printing on self-assembled monolayers of Fmoc-protected aminothiols
Shestopalov, Alexander A.,Clark, Robert L.,Toone, Eric J.
, p. 13818 - 13819 (2007)
Here we describe a new microcontact printing technique (μCP), based on a catalytic reaction between an Fmoc-protected self-assembled monolayer (SAM) of aminothiols chemisorbed on a gold surface and an elastomeric stamp bearing covalently attached piperidine. The elastomeric stamp was used to selectively cleave Fmoc groups from the surface of a SAM on gold in the places of conformal contact. The technique permits nanoscale pattern fabrication with edge resolution less than 50 nm, avoiding problems of conventional microcontact printing associated with diffusion of chemical ink , and provides a simple method for the chemical modification of SAMs. Copyright
Mechanically Interlocked Vitrimers
Zhao, Jun,Zhang, Zhaoming,Cheng, Lin,Bai, Ruixue,Zhao, Dong,Wang, Yongming,Yu, Wei,Yan, Xuzhou
, p. 872 - 882 (2022/01/03)
Mechanically interlocked networks (MINs) have emerged as an encouraging platform for the development of mechanically robust yet adaptive materials. However, the difficulty in reversibly breaking the mechanical bonds poses a real challenge to MINs as custo
Water-soluble and highly emissive near-infrared nano-probes by co-assembly of ionic amphiphiles: Towards application in cell imaging
Xing, Yuzhi,Li, Dahua,Dong, Bin,Wang, Xiaocheng,Wu, Chengfeng,Ding, Lan,Zhou, Shixin,Fan, Jian,Song, Bo
, p. 8059 - 8066 (2019/06/07)
Water-soluble near-infrared (NIR) fluorescent dyes are extremely valuable in cell imaging. We here designed and synthesized an amphiphilic fluorescent dye (denoted by PBI-TPE-11), a bolaamphiphile bearing conjugated tetraphenylethylene and perylene bisimide in the middle and two aliphatic pyridinium groups at both ends. PBI-TPE-11 self-assembled into flake-like nanostructures in aqueous solution and showed very weak fluorescence emission from 600 to 830 nm, covering the NIR region. This result seems discrepant with that previously reported in the literature, where the conjugation of PBI and TPE was proven enhance aggregation induced emission. Very interestingly, both the morphology and the emission intensity were altered by the addition of sodium dodecyl benzene sulfonate (SDBS). Co-assembly of PBI-TPE-11 and SDBS formed nanowires, observed by using an atomic force microscope. Moreover, the emission of the co-assemblies was much stronger than that of the assemblies of neat PBI-TPE-11. An exciting quantum yield (QY) of 15% was obtained for the co-assemblies, while pure PBI-TPE-11 showed a QY of merely 0.2%. Finally, the co-assemblies were successfully applied in labeling HeLa cells, and high viability and high contrast fluorescence images were achieved.
Macrolide Synthesis through Intramolecular Oxidative Cross-Coupling of Alkenes
Jiang, Bing,Zhao, Meng,Li, Shu-Sen,Xu, Yun-He,Loh, Teck-Peng
supporting information, p. 555 - 559 (2018/02/21)
A RhIII-catalyzed intramolecular oxidative cross-coupling between double bonds for the synthesis of macrolides is described. Under the optimized reaction conditions, macrocycles containing a diene moiety can be formed in reasonable yields and with excellent chemo- and stereoselectivity. This method provides an efficient approach to synthesize macrocyclic compounds containing a 1,3-conjugated diene structure.
PREPARATION OF AMINO ACIDS AND AMINO ACID DERIVATIVES
-
Paragraph 0231, (2018/04/20)
The invention relates to a method for synthesizing amino acids or amino acid derivatives involving cross metathesis of functionalized olefins and a tandem amination-reduction process. Amino acids and amino acid derivatives present many interesting physical and chemical properties finding many uses in the automotive, fuel, electronic, and textile industries.
Synthesis and cytostatic evaluation of 4-N-alkanoyl and 4-N-alkyl gemcitabine analogues
Pulido, Jesse,Sobczak, Adam J.,Balzarini, Jan,Wnuk, Stanislaw F.
supporting information, p. 191 - 203 (2014/02/14)
The coupling of gemcitabine with functionalized carboxylic acids (C9-C13) or reactions of 4-N-tosylgemcitabine with the corresponding alkyl amines afforded 4-N-alkanoyl and 4-N-alkyl gemcitabine derivatives. The analogues with a terminal hydroxyl group on the alkyl chain were efficiently fluorinated under conditions that are compatible with protocols for 18F labeling. The 4-N-alkanoylgemcitabines showed potent cytostatic activities in the low nanomolar range against a panel of tumor cell lines, whereas cytotoxicity of the 4-N-alkylgemcitabines were in the low micromolar range. The cytotoxicity for the 4-N-alkanoylgemcitabine analogues was reduced approximately by 2 orders of magnitude in the 2′-deoxycytidine kinase (dCK)-deficient CEM/dCK - cell line, whereas cytotoxicity of the 4-N-alkylgemcitabines was only 2-5 times lower. None of the compounds acted as efficient substrates for cytosolic dCK; therefore, the 4-N-alkanoyl analogues need to be converted first to gemcitabine to display a significant cytostatic potential, whereas 4-N-alkyl derivatives attain modest activity without measurable conversion to gemcitabine.
Improvement of thermal stability of gold nanoparticles by synergistic interligand interactions
Okumura, Atsushi,Tsuchido, Yoshitaka,Yamada, Kou,Todori, Kenji,Machida, Shigeru
scheme or table, p. 708 - 710 (2012/09/22)
Three types of novel gold nanoparticles containing a different condensed ring in their ligands were prepared. Their thermal stability was found to be much higher than that of typical gold nanoparticles surrounded by long-chain alkanethiols because of strong interligand interaction formed by the condensed rings (ππ stacking). A clear correlation was found between the thermal stability and the strength of π π stacking.
One-pot production of fluorescent surface-labeled polymeric nanoparticles via miniemulsion polymerization with bodipy surfmers
Sauer, Ruediger,Turshatov, Andrey,Baluschev, Stanislav,Landfester, Katharina
, p. 3787 - 3796 (2012/08/07)
New molecules combining the functionalities of surface activity, polymerizability, and fluorescent properties within one molecule that could be seen as a fluorescent surfmer (surfactant and monomer) were successfully synthesized. A long hydrocarbon tail c
