Poly(difluorophosphazene): A New Intermediate for the Synthesis of Poly(organophosphazenes)

Although many poly(organophosphazenes) have been synthesized, new preparative pathways are needed, especially for polymers that contain alkyl side groups. A new development involves the use of poly(difluorophosphazene), (NPC1₂) instead of poly-(dichlorophosphazene), (NPC1²)_n, as a substrate for reactions with organometallic reagents. This approach has allowed the preparation of a new class of poly(organophosphazenes) that possess substituent groups linked to the skeleton through direct phosphorus-carbon bonds. The synthesis of uncrosslinked poly-(difluorophosphazene) and its reactions with alkoxides and amines are also reviewed.     

New Ligands: Poly(diphenylphosphorylmethyl)arenes

Abstract

To find out the influence of structure factors on efficincy and selectivity of complexformation the oxides of aromatic tret. di-, tri- and tetraphosphines were synthesized. The molecules contain as conformationaly hard bridges between coordination centres (P?O groups) - fragments of polymethylarenes (isomeric xylenes, mesythylene, durene, dimethylnafthalene, dibenzo-18-crown-6). These compounds were obtained by the Arbusov reaction of Ph₂POEt with corresponding bromomethylarenes. Extraction and complexformation with transplutonium elements, europium, uranium, copper, cobalt were studied. It was found, that among investigated ligands the action selectivity is determined, mainly, by the mutual location of P?O groups. A theoretical conformational analysis using the atom-atom potential function method was applied to the isolated ligands. To reveal conformers suitable for chelating the energy minimisation was carred out with the penalty function constraints keeping the P?O…O?P distance at a specified value. As a result of such analysis the conformers, which are preferable for complexformation with cations of this or that ionic radius, were revealed and the estimation of the selectivity of ligands, which conform with experimental data, was presented.     

New amphiphilic polymers: Poly(N-alkylacrylamide-CO-vinylpyridinium)

A series of new amphiphilic polymers containing various amounts of N-methyl-4-vinylpyridinium units as hydrophilic part and N-dodecylacrylamide or N-decylacrylamide units as hydrophobic part have been prepared by quaternizing the cognate copolymers. Their behaviour in aqueous solutions has been studied by viscometry, as well as by fluorescence spectroscopy and tensiometry. Results are discussed in detail and a conformational model of the macromolecules at the interface (water/methylcyclohexane) is proposed in relation to the formation of microdomains in the aqueous media.     

Poly(phosphoester)s: A New Platform for Degradable Polymers

Poly(phosphoester)s (PPEs) play an important role in nature. They structure and determine life in the form of deoxy‐ and ribonucleic acid (DNA and RNA), and, as pyrophosphates, they store up chemical energy in organisms. Polymer chemistry, however, is dominated by the nondegradable polyolefins and degradable poly(carboxylic ester)s (PCEs) that are produced on a large scale today. Recent studies have illustrated the potential of PPEs for future applications beyond flame retardancy, and provided a coherent vision to implement this classic biopolymer in modern applications that demand biocompatibility and degradability as well as the possibility to adjust the properties to individual needs.     

A New Macroporous Luminescent Hydrogel from Poly(allylamine)

The synthesis of a novel highly swelling, macroporous hydrogel from poly(allylamine) using 3‐chloropentan‐2,4‐dione as a crosslinker is reported. The swelling of the hydrogel was sensitive to changes in pH, temperature, and the extent of crosslinking. The dry gel exhibited a regular honeycomb network with smooth macropores. The hydrogel was inherently luminescent, and so was a metal polychelate.     

New ferrocene-containing structures: Poly(silyl ester)s

Two new polymeric structures containing ferrocene units along the chains, namely poly(silyl ester)s, have been synthesized and characterized: a geminal poly(silyl ester) (g-PSE) and one having a disiloxane spacer between the silyl ester groups (s-PSE). The condensation polymerization of AA/BB monomer systems in solution was used in both cases as preparation method involving a silicon-containing diol, (diphenylsilane diol or 1,3-bis(hydroxy)-tetramethyldisiloxane), and 1,1′-di(chlorocarbonyl)ferrocene. The polymers were investigated by differential pulse voltammetry in order to evaluate the redox behavior. Due to the presence of the silyl ester groups in the chain, these polymers are hydrolytically degradable.     

A New Synthetic Method for Amino-Terminated Poly (Ethyleneglycol) Derivatives

Coupling of poly(ethyleneglycol)s with primary and secondary diamines via imidazolylformates provides a convenient method for preparing the title compounds.     

新型电活性聚(2,2'-二氨基苯氧基二硫化物)的电化学合成

在Pt电极上,LiClO4和不同酸的乙腈/四氢呋喃溶液中,通过动电位连续扫描法合成了新型电活性聚（2,2'-二氨基苯氧基二硫化物）（PDAPD）,研究了电解质LiClO4及不同酸（HCl、CF3COOH、CCl3COOH、CH3COOH）的浓度对合成产物的影响,实验结果表明：浓度为0.1mol/L的LiClO4及浓度在0.05-0.5mol/L之间的HCl是获得高电活性的聚合物导电膜的最佳实验条件。     

Poly(trialkoxysilyltricyclononenes): A New Type of Polymers for Membrane Gas Separation

New metathesis and addition polymers containing Si–O–C groups were synthesized from 3-tri(n-propoxy) silyltricyclo[4.2.1.0^2.5]non-7-ene. It was shown for the first time that metathesis polymer was more permeable than the addition polymer. The prepared polymers showed high selectivity in the butane/methane separation controlled by solubility; therefore, they are promising for membrane separation of hydrocarbon mixtures.     

New Polymers Derived from Poly(Methylphenylphosphazene)

Abstract

The sequential treatment of [Me(Ph)PN]_n with n-BuLi and electrophiles such as substituted chlorosilanes, aldehydes and ketones, and carbon dioxide results in new functionalized polyphosphazenes. Graft copolymers have also been prepared by using the anionic polymer intermediate to initiate anionic addition polymerization of styrene, CH₂=C(Ph)H, and ring opening polymerization of hexamethylcyclotrisiloxane, [Me₂SiO]₃.     

New Routes to Poly(Alkylene Sulfidoselenides)

A procedure was developed for preparing mixed poly(alkylene sulfidoselenides) by simultaneous dissolution of sulfur and selenium in basic reducing systems NaOH (KOH)-N₂H₄·H₂O-H₂O, followed by alkylation of the resulting solutions with bielectrophilic agents.     

聚(2,5-二烷氧基对苯乙炔)的合成新方法

二烷氧基苯;化学脱氢反应;聚(2;5-二烷氧基对苯乙炔)的合成新方法     

A New Antimicrobial Agent: Poly (3‐hydroxybutyric acid) Oligomer

In this work, it is first reported that the poly (3‐hydroxybutyric acid) (PHB) oligomer with a few degrees of polymerization possesses effective antibacterial and antifungal properties. Two preparation methods for the PHB oligomer are described, namely, one‐step ring‐opening polymerization of β‐butyrolactone and extraction from the fermented PHB polymer. An appropriate amount of the synthesized PHB oligomer shows no physiological toxicity to the skin and major organs of mice. Topological application of the synthesized PHB oligomer imparts antimicrobial ability to non‐antibacterial fabrics with washing resistance. The synthesized PHB oligomer offers effective sterilization and promotes wound healing in infected nude mice. Most importantly, the PHB oligomer is also reactive to drug‐resistant bacteria. These results suggest that the PHB oligomer is not only a great candidate for antimicrobial modification but also a promising one for biomedical applications. Finally, the antimicrobial mechanisms of the PHB oligomer are revealed, and these include disruption of biofilm and the bacterial wall/membrane, leakage of the intracellular content, inhibition of protein activity, and change in the transmembrane potential.     

A new temperature-sensitive polymer: Poly(ethoxypropylacrylamide)

In this study, a new temperature sensitive polymer was obtained by the solution polymerization of ethoxypropylacrylamide. The monomer, N-(3-ethoxypropyl)-acrylamide was synthesized by the nucleophilic substitution reaction of 3-ethoxy-propylamine and acryloyl chloride. The solution polymerization was performed in ethanol at 70 °C, by using azobisizobutyronitrile as the initiator. Poly(N-(3-ethoxypropyl)acrylamide), PEPA, exhibited a reversible phase transition by the temperature. The effects of polymer and salt concentrations on the lower critical solution temperature, (LCST) behaviour were investigated. LCST was found to be strongly dependent on the polymer concentration. The dynamic light scattering (DLS) measurements confirmed the formation of aggregates by the association of nucleated polymer chains at the temperatures higher than LCST. However an unusual behaviour, a marked decrease in the hydrodynamic diameter by the increasing PEPA concentration was observed below the LCST. The effect of salt concentration on the critical flocculation temperature of PEPA was reasonably similar to poly(isopropylacrylamide), PNIPA. In the ethanol-water media, the reversible phase transition behaviour was observed up the ethanol concentration of 30% v/v. This study indicated that PEPA was a new alternative thermally reversible material for PNIPA. With respect to the well-defined temperature-sensitive polymers like PNIPA, polymer concentration dependent LCST of PEPA can provide significant advantages in the applications like drug targeting, affinity separation and immobilization of bioactive agents.     

Custom‐Fit Ruthenium(II) Metallopeptides: A New Twist to DNA Binding With Coordination Compounds

A new bipyridine building block has been used for the solid‐phase synthesis of dinuclear DNA‐binding ruthenium(II) metallopeptides. Detailed spectroscopic studies suggest that these compounds bind to the DNA by insertion into the DNA minor groove. Moreover, the potential of the solid‐phase peptide synthesis approach is demonstrated by the straightforward synthesis of an octaarginine derivative that shows effective cellular internalization and cytotoxicity linked with strong DNA interaction, as evidenced by steady‐state fluorescence spectroscopy and AFM studies.