新型热反应大分子单体的合成与表征

溶液法合成了一些低分子量的羟端基低聚苯醚砜,并由相转移催化剂将之转为热反应大分子单体——α,ω-双甲基丙烯酸聚苯醚砜酯;用FTIR、~1H-NMR对其结构进行了表征,GPC、VPO对其分子量进行了分析和测定;用DSC、DTA对聚苯醚砜双烯大分子单体的转变温度、热反应过程进行了测定和分析。     

1H-INDENYLFURAN AND THIOPHENE DERIVATIVES– A NEW CLASS OF SINGLET OXYGEN SENSITIZERS

Abstract— Photophysical and photochemical properties of 1H-indenylfuran and thiophene derivatives were studied. UV spectra showed that all the compounds tested absorbed UV light in the region 350–380 nm. The fluorescence spectra of 4a-e showed bands in the region 410–470 nm and quantum yields (φ_F) in the range 0.25–0.88. Attempts to calculate the triplet energy of 4a-e failed except for 4c and 4d , which showed E_T= 43–44 kcal mol^-1. These compounds are a new class of singlet oxygen sensitizers. The sensitized reaction of 2,5-dimethylfuran with singlet oxygen was followed showing that 4a and 4e are more reactive than α-terthiophene (4.0 and 2.5 times respectively), while the other compounds show the same reactivity as 1 . This behavior can be explained considering the different intersystem crossing quantum yields of compounds 4a-e . Diazabicyclo[2. 2. 2]octane is a quencher of singlet oxygen in this reaction, while we can exclude superoxide ion formation using the photooxidation of α, α-dimethylstilbene.     

FIRST GLYCOSIDE SYNTHESIS VIA PIPERIDINIUM SALTS OF HETEROCYCLIC NITROGEN BASES: THE SYNTHESIS OF A NEW CLASS OF DIHYDROPYRIDINE THIOGLYCOSIDES

A first reported method for preparation of a new class of thioglycosides via reaction of piperidinium salts of dihydropyridinethiones with 2,3,4,6-tetra-O-acetyl-α-d-gluco- and galactopyranosyl bromides has been studied. Comparison with the products obtained from silylated thiopyridines is made.     

ADVANCES IN STUDY OF A NEW CLASS OF PILLARED LAYERED MICROPOROUS MATERIALS?¤?¤POLYOXOMETALATE-TYPE HYDROTALCITE-LIKE CATALYSTS

In the present paper, on the basis of our work. advances in study of the catalysts of polyacid-type hydrotalcite-like are reported and reviewed. Using polyoxometalates (POM) as pillaring species and layered double hydroxides (LDH) as host matter, a new class of catalytic materials, LDHPOM, has been synthesized by five different methods. Their acidic and oxidative catalytic properties have been investigated by several research groups. The above mentioned information is given in this review.     

Phase behavior of amphiphilic polymers: A dissipative particles dynamics study

Dissipative particle dynamics is a mesoscopic simulation method which allows one to predict the self-assembly of amphiphilic polymers and surfactants. It was possible to reproduce the formation of microemulsions of the oil/water (o/w), water/oil (w/o), and L₃-type of C10E4 in water and n-decane with excellent accuracy. We are able to predict the experimentally not investigated emulsion formation of a poly(ethylene butylene)–poly(ethylene oxide) in water and methylcyclohexane.     

STATISTICS OF A NOVEL CLASS OF LIQUID CRYSTAL POLYMERS

A novel class of the liquid crystal polymers with mesogens laterally attached to flexible main chain backbones has been synthesized recently by us. While the flexible backbones tend to take configuration of maximum entropy the mesogenic side groups tend to orientate because of the anisotropie soft dispersion forces. A mean field theory is presented to describe the competition between these two trends which makes it possible for this class of polymers to show anisotropic (liquid crystal) phase within certain temperature range where the polymer main chains and the side chain mesogens will take approximately parallel arrangement, which is different from the normal side chain liquid crystal polymers. The temperature range of the liquid crystal phase, its ordering and phase transition all depend on the flexibility of the backbone, the strengthof the anisotropic forces of the side groups and the hinge elasticity. The results show that the liquid crystalisotropic phase transition is of the first order. The phase diagram, i. e. the dependence of the transition temperature on the structure of the polymers is also given.     

A color version of the Hinsberg test: permethylated cyclodextrin and crown-appended azophenol for highly selective sensing of amines

Azophenol dyes 1-5 having the permethylated cyclodextrin and/or crown moieties have been synthesized. Compounds 1 and 2 provide critical information for discrimination among 1°-3° amines by unique color changes. Addition of 1° and 2° amines to solutions of 1 or 2 in chloroform shifts the absorbance maximum of the initial solutions from 380 nm to ∼580 nm and ∼530 nm, respectively, but no change is observed with 3° amines. The high selectivity of 1 is mainly due to H-bonding between the ammonium H atoms of the amine and oxygen atoms of the crown-6. The selectivity of 1 possessing the β-cyclodextrin moiety toward amines was higher than that of 2 possessing the α-cyclodextrin moiety. On the other hand, chloroform solutions of 3 or 4, which lack the crown ether moiety, changed from yellow (380 nm) to pink (500 nm) with the addition of 1° and 2° amines, but with no selectivity. These results indicate that the crown unit in 1 or 2 plays an important role in discriminating among the types of amines.     

Thio-functionalised glucosinolates: unexpected transformation of desulfoglucoraphenin

Enzymatic desulfation of stable glucoraphenin affords desulfoglucoraphenin, which unexpectedly undergoes further transformations into cyclic nitrone-type derivatives.     

新型聚氨酯胺类催化剂

合成了6个新型聚氨酯胺类催化剂——2-氮杂双环〔2、2、1〕庚烷衍生物,对该类催化剂作出了初步评价。结果表明,这是一类具有优良应用前景的聚氨酯泡沫材料催化剂。同时,讨论了立体构型和催化活性的关系。     

A DMAP-functionalized oligocholate foldamer for solvent-responsive catalysis

A hexameric cholate foldamer functionalized with a 4-dialkylaminopyridyl group displayed solvent-sensitive catalysis for the acetylation of alcohols. The catalyst folded in carbon tetrachloride containing a low percentage (<4%) of DMSO and unfolded as more DMSO was added. By increasing the effective concentration of the substrate near the catalytic group, the folded catalyst was more active than the unfolded catalyst toward small, hydrophilic alcohols. The longer and hydrophobic n-octanol, however, was more reactive in the presence of the unfolded catalyst. The highest selectivity (21:1) was observed for methanol/n-octanol with the folded oligocholate catalyst.     

A Poly(para-phenylene) with Hydrophobic and Hydrophilic Dendrons: Prototype of an Amphiphilic Cylinder with the Potential to Segregate Lengthwise

Langmuir monolayers are formed from an amphiphilically decorated poly(para-phenylene), which indicates that its hydrophilic and hydrophobic parts segregate lengthwise along the polymer backbone in this nanometer-sized cylinder as illustrated in A . This polymer differs from known amphiphiles in that it consists of a linear, covalently bound sequence of “little” amphiphiles. It is much more rigid than common “polysoaps”, which should increase its potential to aggregate, for example, into channels.     

Interfaces with Fluorinated Amphiphiles: Superstructures and Microfluidics

This Minireview discusses recent developments in research on the interfacial phenomena of fluorinated amphiphiles, with a focus on applications that exploit the unique and manifold interfacial properties associated with these amphiphiles. Most notably, fluorinated amphiphiles form stable aggregates with often distinctly different morphologies compared to their nonfluorinated counterparts. Consequently, fluorinated surfactants have found wide use in high-performance applications such as microfluidic-assisted screening. Additionally, their fluorine-specific behaviour at solid/liquid interfaces, such as the formation of superhydrophobic coatings after deposition on surfaces, will be discussed. As fluorinated surfactants and perfluorinated materials in general pose potential environmental threats, recent developments in their remediation based on their adsorption onto fluorinated surfaces will be evaluated.     

Spontaneous vesicles of single-chain sugar-based fluorocarbon surfactants

The synthesis and physico-chemical investigation of a cationic, water-soluble surfactant of formula C₈F₁₇CH₂CH(OH)CH₂NH₂⁺CH₂CH(OH)CH₂OH, Lac⁻ (Lac = lactobionate), bearing a single-fluorocarbon tail and the lactobionate moiety as a counterion is reported. It forms spontaneously in water bilayer vesicles with a polydisperse distribution in size. This behavior could be attributed to a possible asymmetry of the bilayers due to an excess of the counterion outside the vesicles and possible stabilization by hydrogen bond interactions between the aminoalcohol polar heads of the cationic surfactant inside the vesicle.     

SYNTHESIS OF A NEW ORGANIC AEROGEL

A new organic aerogel made from (N- hydroxymethyl)-acrylamide (NA) and resorcinolis reported. The acidic solution of NA and resorcinol was irradiated by γ-rays with 1200-1800 Gy dose, then was heated to 60℃ for at least 16hr to form transparent sol-gel.The translucent aerogel can be obtained from the sol-gel with CO_2 as supercritical fluid.Synthetic conditions (e.g. acidity of the solution, ratio of NA to resorcinol) are discussed.     

合成马来二醛的新方法

马来二醛(HCOCH=CHCHO)是一种α、β-不饱和醛,它可用于制造食品和香烟的增香剂,照相凝胶的固化剂和漂白棉织物的活化剂等。     

Talc-filled PP: A new concept to maintain long term heat stability

Talc as filler improves the mechanical properties of polypropylene. However, talc also reduces the efficiency of many stabilizers and so the life-time of a final product.In a study to find new modifiers to improve the heat stability of talc-filled PP formulations it was observed that selected blends of modifiers were more efficient than the single modifiers at the same total loading.     

A Lysoganglioside/Poly-L-glutamic Acid Conjugate as a Picomolar Inhibitor of Influenza Hemagglutinin

Based on the principle of a multivalent interaction, the amphiphilic polymer 1 , present in solution as an aggregate (see below right), is able to inhibit infection with the influenza virus. After recognition of a specific sialyllactose epitope through hemaglutinin (HA) on the virus surface, the sphingosine residues and the fluorescent tag form a stable complex with HA through hydrophobic interactions. Polymer 1 shows in vitro inhibitory activity 10⁶-fold greater than that of sialyllactose. PGA=polyglutamic acid.     

An Improved Synthetic Procedure for the Preparation of N‐Acyl (2‐aminoethyl)‐β‐d‐glycopyranoside Lipids and Characterization of Their Mesogenic Properties

Abstract

A modified synthetic procedure was used for the synthesis of N‐acyl (2‐aminoethyl) glycosides bearing lactose, maltose, and melibiose carbohydrate headgroups and different acyl chains. The lipid glycosides were prepared in gram scale and investigated for their liquid crystalline properties. It was found that the polar spacer suppresses polymorphism, and the resulting simplified phase behavior was found in the pure state upon heating, as well as for the lyotropic phases