Synthesis and surfactant properties of a new “extended” glucidoamphiphile made from D-glucose

We prepared a new nonionic surfactant, 8, in which the n-dodecyl chain is attached at the C-3 carbon of the D-glucose-based glucopyranose moiety by the linkage Z=?O-(α-PP-O) _n with ?O-(α-PP-O) _n being a commercial poly-(α-propyloxy) oligomeric mixture (with average ñ=6). This amphiphilic behavior study showed that, when compared to the reference compound 3-O-dodecyl-D-glucopyranose (Z=O), compound 8 exhibits (i) a water solubility that is 100-fold higher, (ii) a hydrophilic-lipophilic balance value increase from 8.5 to 12.6 units, and (iii) a slighly lower critical micelle concentration.     

Synthesis of “L-cysteine–graphene oxide” hybrid by new methods and elucidation of its uptake properties for Hg(II) ion

This study introduces two new, simple, and scalable methods for synthesis of “cysteine–graphene oxide” hybrid, namely nucleophilic and covalent methods. Produced adsorbents could uptake 500 and 600 mg Hg²⁺/g, respectively, which are larger than capacities of most of the commercial adsorbents. By means of different instrumental techniques, chemical structures of the obtained graphene products were disclosed, and two pertinent mechanisms for their formations were suggested. Time for attaining uptake equilibrium for nucleophilic/covalent samples was 30 min/150 min, and kinetics was controlled by liquid film resistance/chemical reaction mechanisms, respectively. High selectivity and good regenerability are other key features of the prepared adsorbents.     

Monomers for adhesive polymers, 18. Synthesis,photopolymerization and adhesive properties of polymerizable α-phosphonooxy phosphonic acids

Four polymerizable α-phosphonooxy phosphonic acids 7a, 7b, 9 and 16 were synthesized in seven steps. They were characterized by ¹H, ¹³C and ³¹P NMR spectroscopy and by high-resolution mass spectroscopy. The copolymerization of acidic monomers 7a, 7b, 9 and 16 with 2-hydroxyethyl methacrylate was studied using a differential scanning calorimeter. Due to the presence of two acidic groups, those monomers are significantly more reactive than 10-methacryloyloxydecylphosphonic acid (MDPA) and 10-methacryloyloxydecyl dihydrogen phosphate (MDP). Self-etch adhesives based on monomers 7a, 7b, 9 and 16 were formulated and used to mediate a bond between a dental composite and the dental hard tissues (dentin and enamel). These adhesives exhibit excellent performances and provide significantly higher dentin and enamel shear bond strength than adhesives based on MDP or MDPA.     

A new family of “ligated” anionic initiators for the “living” polymerization of (meth)acrylic esters

Summary A new family of ligands (dual - ligand), i.e. chelating lithium alkoxides, Li-O-(CH₂-CH₂O)_nCH₃, is shown to be very effective in promoting the living anionic polymerization of methacrylic and acrylic esters, including a number of primary alkyl acrylates such as n-butyl acrylate and 2-ethylhexylacrylate.     

Synthesis of a new “green” sponge via transesterification of dimethyl carbonate with polyvinyl alcohol and foaming approach

In this article, the low toxicity of polyvinyl alcohol (PVA) and dimethyl carbonate (DMC) were used to synthesize polyvinyl alcohol carbonate (PVAC) sponge via a simple transesterification-foaming approach, and the structure and morphology of PVAC sponge were characterized; moreover, the influence of dosage of K₂CO₃, PVA, distilled water and n-pentane on the water retention capacity of PVAC sponge were investigated, and the influence of reaction temperature and reaction time on the water retention capacity of PVAC sponge were also surveyed. Based on those, it was confirmed that 9.00 g PVA and 5.00 mL DMC in the presence of 2.00 g K₂CO₃ and 50.00 mL water could be used to synthesize PVAC polymer at 75?°C and for 2.5 h via the transesterification approach, and PVAC polymer in the presence of 5.00 mL n-pentane could be used to synthesize PVAC sponge at 55?°C and for 10 h via the foaming approach, and PVAC sponge owned the structure of six-membered lactone ring and the polyporous morphology, and the maximal water retention capacity was 21.50 g/g.     

“Hard” vs. “Soft” Templating Synthesis of Mesoporous Nb2O5 Catalysts for Oxidation Reactions

Nanoporous niobia with crystalline walls has been formed within the mesopores and on the outer surface of SBA-15 and FDU-1 by impregnation with niobium salts followed by calcination and silica template removal. The influence of niobium source and silica templates on the physicochemical properties of niobia particles was evaluated by powder X-ray diffraction, nitrogen adsorption, scanning electron microscopy, temperature-programmed reduction and thermogravimetry. The resulting nanoniobia was tested in the liquid phase oxidation of cyclohexene with hydrogen peroxide and appeared to be catalytically active contrary to amorphous niobia.     

Synthesis and self-assembly of fluorene-vinylene alternating copolymers in “Hairy-Rod” architecture: side chain – mediated tuning of conformation,microstructure and photophysical properties

In the present work, we demonstrate that the side chain choice, as a tunable parameter, is an effective strategy to drive molecular ordering, packing motifs and overall microstructure of a conjugated polymer. By applying Wittig polycondensation novel ‘rod-coil’ structures, in ‘hairy-rod’ architecture, based on fluorenylene vinylene copolymers with well-defined oligomeric side chains were synthesized using ‘T’-shaped or ‘Cross’-shaped p-terphenyl macromonomers. The overall character of the copolymers was systematically varied by attaching of hydrophilic PEG 2000, hydrophobic polar oligo-ε-caprolactone or hydrophobic and non-polar oligostyrene side chains. Self-assembling of the copolymers by simple direct dissolution method was achieved in various solvents by modifying their selectivity in relation to the side chain or main chain. The morphology investigations demonstrated that unique nanofeatures obtained in each case (helical foldamers, vesicles, disks, or helical turns) depend on the nature, number, and position of the side chains which influence the photophysical properties. The ‘hairy-rod’ topology is also responsible for the self-assembly of the materials in molten state, as thermal analysis revealed, and the propensity of the new synthesized conjugated main chain for helical folding was evidenced, as well.     

Synthesis and investigation of monomodal hydroxy-functionalized PEG methacrylate based copolymers with high polymerization degrees. Modification by “grafting from”

The synthesis of monomodal copolymers with poly(ethylene glycol) (PEG) side chains from commercial poly(ethylene glycol) methacrylates (PEGMA) by atom transfer radical polymerization (ATRP) is verified. Two hydroxy-functionalized PEGMA macromonomers (520 g/mol and 360 g/mol) were copolymerized with methyl methacrylate (MMA) using various initial feed (1.5/98.5–50/50 mol.%). The copolymers P(MMA-co-PEGMA) with high degree of polymerization, e.g. 100–275 of repeating units in the backbone including 7–56 PEG side chains, were obtained. The relative reactivity ratios of PEGMA and MMA determined by the Jaacks method indicated slightly faster incorporation of macromonomer into polymeric chain than MMA (r_MMA = 0.79; r_PEGMA = 1.27). The polymers containing at least 17 mol.% of PEGMA units were water-soluble and exhibited clouding point at temperature in a broad range of 39–70 °C. The temperature-sensitive effect makes these polymers as a potential carriers in drug delivery systems. In the case of copolymers insoluble in water, a three-step procedure, including esterification to ATRP multifunctional macroinitiators, ATRP of tert-butyl methacrylate (tBMA) by grafting from, deprotection of carboxylic groups by removing tert-butyl groups, was applied to extend PEG grafts and expand the content of hydrophilic fraction (32–94 mol.%), what efficiently developed polymer solubility in polar solvents giving possibility for the future biomedical applications.     

A “Golden Age” for the discovery of new antileishmanial agents: Current status of leishmanicidal gold complexes and prospective targets beyond the trypanothione system

Leishmaniasis is one of the most neglected diseases worldwide and is considered a serious public health issue. The current therapeutic options have several disadvantages that make the search for new therapeutics urgent. Gold compounds are emerging as promising candidates based on encouraging in vitro and limited in vivo results for several Au^I and Au^III complexes. The antiparasitic mechanisms of these molecules remain only partially understood. However, a few studies have proposed the trypanothione redox system as a target, similar to the mammalian thioredoxin system, pointed out as the main target for several gold compounds with significant antitumor activity. In this review, we present the current status of the investigation and design of gold compounds directed at treating leishmaniasis. In addition, we explore potential targets in Leishmania parasites beyond the trypanothione system, taking into account previous studies and structure modulation performed for gold-based compounds.     

Adhere to the principle of “Science and technology is the No. 1 productive force”, strive for the realization of the strategic target of“Boosting chemical industry by science and technology”

In this pen conference, we have invited authorities and experts concerned to further elaborate the connotations and significance of the principle of "Science and technology is the No. 1 productive force" , discuss the problems encountered in implementing the principle in chemical industry and measures consequently taken against them and exchange experience gained in executing the policy of "Boosting chemical industry by science and technology" , The purpose is to accelerate the modernization process of China's chemical industry and realize the strategic target set by the government.