Phosphazene Copolymers Research Articles

Optimizing Hydrophobic Groups in Amphiphiles to Induce Gold Nanoparticle Complex Vesicles for Stability Regulation.

Polymeric graft polyphosphazene containing 4-aminobenzoic acid diethylaminoethyl ester (DEAAB) as hydrophobic side groups was rationally designed and named PDEP. PDEP can self-assemble into a nanovesicle in water. More importantly, when compared with the amphiphile poly[(methoxy-poly(ethylene glycol))(ethyl p-aminobenzoate)]phosphazene (PEP) copolymer containing benzene rings and the amphiphile poly[(methoxy-poly(ethylene glycol)(N,N-diisopropylethylenediamine)]phosphazene (PDP) copolymer containing tertiary amino groups, the coexistence of benzene and tertiary amino groups in PDEP enabled it to effectively load water-soluble small-molecule doxorubicin hydrochloride (DOX·HCl) into the vesicle and efficiently induce in situ transformation of gold tetrachloroaurate (HAuCl4) to gold nanoparticles (AuNPs) as both a reductant and a stabilizer. By optimizing the reduction conditions, such as the temperature, reaction time, and hydrophobic group in polymer/HAuCl4 molar ratio, the AuNP complex PDEP vesicles significantly inhibited the DOX·HCl burst release at pH 7.4 while displaying a fast release responsive to pH 5.5.

Synthesis of (Silylamino)Phospholenes and their Derivatives: Synthesis of a New Spirocyclic Phosphazene

GRAPHICAL ABSTRACTPhospholenes containing one or two methyl groups at the 3 and 4 positions on the heterocyclic ring and bis(trimethylsilyl)amino groups on phosphorus were prepared by treating 1-bromo or 1-chlorophospholenes with lithium bis(trimethylsilyl)amide. Several P(V) derivatives of these 2-and 3-phospholenes were prepared by oxidation with hexachloroethane. The chloro groups in the resulting P-chloro-N-trimethylsilyl derivatives were subsequently replaced by phenoxy groups to afford P-phenoxy-N-trimethylsilyl substituted ring compounds. The P-phenoxy-N-trimethylsilyl derivative was hydrolyzed to the corresponding P-amino phosphine oxide; treated with trifluoroethanol to form a new trispirocyclic phosphazene; and copolymerized with Me2P(OPh) = NSiMe3 to give a new phosphazene copolymer containing the phospholene ring (Mw = 3.8 × 104 Da). These new compounds were characterized by 1H, 13C, and 31P NMR spectroscopy. The spirocyclic phosphazene was also characterized by X-ray crystallography.

Rheological behavior and microstructure of 2,2′-dioxy- 1,1′-binaphthylphosphazene R/S random copolymer

Solutions of a binaphthoxy phosphazene copolymer (containing chiral 2,2′-dioxy-1,1′-binaphthyl units with 50% R and S configurations distributed along the chains) in N-methyl pyrrolidone were studied by means of continuous flow experiments and small amplitude oscillatory flow tests. A sudden viscosity decrease was observed in the polymer concentration range (39–40 wt %), evidencing a liquid-crystalline polymer behavior. This has been confirmed by other rheological methods which have demonstrated that, for a sufficiently high concentration, the solutions of the binaphthoxy phosphazene copolymer give rise to a lyotropic system with formation of rigid rods (axial ratio of 10) stacked parallel to each other. The lyotropic properties of our binaphthoxy phosphazene copolymer are compatible with a regular helical structure, similar to that found for a homoleptic binaphthoxy phosphazene, which contains only S configuration. This suggests that the chains of 50% R/S binaphthoxy phosphazene copolymer are, in average, close to the strictly alternating R-S copolymeric structure of the syndiotactic isomer. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010

Random Copolymers with 2,2′-Dioxy-1,1′-biphenyl-phosphazene and Chiral 2,2′-dioxy-1,1′-binaphthylphosphazene Units Functionalized in the 6,6′-Positions with PPh2 Groups as Precursors for Ru(arene) Catalysts

The chiral phosphazene copolymers {[NP(O2C12H8)]0.9[NP(O2C20H12)]0.1} (1) and {[NP(O2C12H8)]0.9[NP(O2C20H10Br2)]0.1} n (2) [(O2C12H8) = 2,2′-dioxy-1,1′-biphenyl; (O2C20H12) = R-2,2′-dioxy-1,1′-binaphthyl and (O2C20H10Br2) = R-6,6′-dibromo-2,2′-dioxy-1,1′-binaphthyl] were prepared by sequential substitution from [NPCl2] n and the corresponding dihydroxy-biphenyl or binaphthyl reagents in the presence of Cs2CO3 and K2CO3. The reaction of (2) with tBuLi in THF, followed by addition of PPh2Cl and a treatment with SiHCl3/PPh3 to eliminate any oxidized OC6H4P(O)Ph2 groups, gave the phosphine containing copolymer {[NP(O2C12H8)]0.9[NP(O2C20H10[PPh2]2)]0.1} n (3), that was used as a chiral ligand to support [Ru(p-cymene)Cl] complexes. The resulting catalyst was active for hydrogen transfer from isopropyl alcohol to acetophenone but the placement of the Ru centers in the 6,6′-positions of the binaphthoxyphosphazene units induced no enantioselectivity.

High molecular weight poly-biphenoxyphosphazene copolymers with cyclic secondary amino groups

The reaction of poly(dichlorophosphazene) [NPCl 2] n with 2,2′-dihydroxybiphenyl, 2,2′-(OH)C 6H 4–C 6H 4(OH), and then with p-anisidine, p-NH 2C 6H 4OMe, in the presence of K 2CO 3 led to the formation of the chlorine containing phosphazene copolymer {[NP(O 2C 12H 8)] 0.75[NP(NHC 6H 4OMe) 2] 0.15[NP(NHC 6H 4OMe)Cl] 0.05[NPCl 2] 0.05} n ( 1), which could be isolated and fully characterised. When using cyclic secondary amines instead of aromatic primary amines, namely, HNC 5H 10 (piperidine), HNC 4H 8O (morpholine), HNC 4H 8S (thiomorpholine), the reaction gave the functionalized copolymers {[NP(O 2C 12H 8)] 0.6[NP(NC 5H 10) 2] 0.4} n ( 2), {[NP(O 2C 12H 8)] 0.65[NP(NC 4H 8O) 2] 0.35} n ( 3) and {[NP(O 2C 12H 8)] 0.75[NP(NC 4H 8S) 2] 0.25} n ( 4), respectively. The broad bands in their 31P NMR spectra and the bimodal aspect of their GPC chromatograms suggested they could be forming aggregates in solution.

Synthesis and thermal decarbonylation of W(CO) 5 complexes supported by nitrile, pyridine or phosphine ligands to poly-spirophosphazene random copolymers carrying O–C 6H 5–CO 2Pr groups

The phosphazene copolymers {[NP(O 2C 12H 8)] 0.5[NP(O–C 6H 4–CO 2Pr n )(O–C 6H 4–L)] 0.5} n [L = CN ( 1), PPh 2 ( 2)] and {[NP(O 2C 12H 8)] 0.6[NP(O–C 6H 4–CO 2Pr n )(O–C 5H 4N)] 0.4} n ( 3) have been synthesized by sequential substitution from [NPCl 2] n . Their reactions with [W(MeOH)(CO) 5] gives the corresponding tungsten carbonyl complexes {[NP(O 2C 12H 8)] 0.5[NP(O–C 6H 4–CO 2Pr n )(O–C 6H 4–CN)(W(CO) 5) 0.4] 0.5} n ( 4), {[NP(O 2C 12H 8)] 0.5[NP(O-C 6H 4–CO 2Pr n )(O–C 6H 4–PPh 2)(W(CO) 5) 0.7] 0.5} n ( 5), {[NP(O 2C 12H 8)] 0.6[NP(O–C 6H 4–CO 2Pr n )(O–C 5H 4N–W(CO) 5)] 0.4} n ( 6a), and {[NP(O 2C 12H 8)] 0.6[NP(O–C 6H 4–CO 2Pr n )(O–C 5H 4N)(W(CO) 5) 0.4] 0.4} n ( 6b), that have been fully characterized by IR and NMR spectroscopies. The thermal properties (TGA and DSC) of the polymeric complexes showed that they are high glass transition materials that undergo a complete decarbonylation below 300 °C forming metal containing species that have a stabilizing effect on the polymeric matrices. The final residues up to 800 °C are of the order of30–50%.

Water-Soluble Biodegradable Polyphosphazenes Containing N-Ethylpyrrolidone Groups

Novel water-soluble biodegradable polyphosphazenes are described. Polymers are constructed on the basis of a biodegradable polyphosphazene backbone to mimic the structure of poly(vinylpyrrolidone), PVP. Poly{di[2-(2-oxo-1-pyrrolidinyl)ethoxy]phosphazene}, PYRP, and its copolymers containing biologically active carboxylatophenoxy side groups have been synthesized. The ability of these polymers to degrade in aqueous environment at 37 °C is demonstrated by light scattering-GPC and NMR studies. The degradation is manifested by the gradual decrease in the molecular weight and release of the side group −1-(2-hydroxyethyl)-2-pyrrolidone. It has been shown that the incorporation of N-ethylpyrrolidone containing side groups in the polymer structure can modulate degradation profiles of phosphazene copolymers. The kinetics of hydrolytic degradation and the effect of pH on the degradation rate have been investigated.

High Molecular Weight Phosphazene Copolymers Having Chemical Functions Inside Chiral Pockets Formed by (R)‐(1,1′‐Binaphthyl‐2,2′‐dioxy)phosphazene Units

AbstractThe polyphosphazene {[NPCl2]x[NP(O2C20H12)]1−x}n (O2C20H12 = 1,1′‐binaphthyl‐2,2′‐dioxy) reacted in refluxing THF in the presence of Cs2CO3 with HOC5H4N or para‐substituted phenols HOC6H4R to give the random copolymers {[NP(OC5H4N)2]x[NP(O2C20H12)]1−x}n (1) or {[NP(OC6H4R)2]x[NP(O2C20H12)]1−x}n [R = CN (2), COMe (3), CO2nPr (4), PPh2 (5)] and with H2NnBu to give {[NP(NHnBu)2]x[NP(O2C20H12)]1−x}n (6). The reaction of the polymer {[NPCl2]x[NP(O2C20H10Br2)]1−x}n (O2C20H10Br2 = 6,6′‐dibromo‐1,1′‐binaphthyl‐2,2′‐dioxy) with HOC6H4PPh2 and Cs2CO3 gave {[NP(OC6H4PPh2)2]x[NP(O2C20H10Br2)]1−x}n (7). Those polymers have a very high glass‐transition temperature (Tg) and a chemical function or ligand that is in the interior of a chiral pocket. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

Blending, Grafting, and Cross-Linking Processes between Poly(ethylene oxide) and a (4-Benzoylphenoxy)∼0.5(Methoxyethoxyethoxy)∼0.5Phospha- zene Copolymer

We report our results on the miscibility and irradiation of the blends of poly(ethylene oxide) (PEO) and a phosphazene copolymer almost equimolecularly substituted with 4-benzoylphenoxy and methoxyethoxyethoxy moieties (BzMEEP). Differential scanning calorimetry (DSC) studies of the blends showed glass transitions temperatures (Tg) that increased regularly with the percentage of BzMEEP in the blend from about −50 °C up to −30 °C. Irradiation of these blends, under selected experimental conditions, leads to the absorption of the light by the benzophenone chromophore only in the copolymer, causing grafting of PEO onto the copolymer to occur concurrently with cross-linking reactions. Almost completely insoluble gellike materials were obtained. The percent of gel formed and degree of swelling of the cross-linked blends in chloroform were dependent on the amount of benzophenone, irradiation time, and molar mass of PEO.

Polyphosphazene Electrolytes. 2. Synthesis and Properties of New Polymer Electrolytes Based on Poly((amino)[(2-methoxyethoxy)ethoxy])phosphazenes

A series of ether group and amino group cosubstitutent phosphazene copolymers was synthesized and characterized by a combination of NMR, elemental analysis, and FTIR spectroscopy. The length of the alkyl group in the amino side chain and the content of the methoxyethoxyethoxy (MEE) substituent on the polymer properties were varied. Dynamic mechanical analysis (DMA) demonstrated that the cosubstitutent polymers prepared have better mechanical properties than the ether homopolyphosphazene, poly[bis(2-methoxyethoxy)ethoxy]phosphazene, MEEP. The copolymers that possessed multiple electron-donor coordination sites, nitrogen and oxygen atoms, were complexed with various amounts of lithium perchlorate (LiClO4) to form polymer electrolytes. The ionic conductivity of the polymer electrolytes were determined by an impedance analyzer in a temperature range of 30−80 °C. According to those results, the conductivities of the prepared polymer electrolytes increased according to the rise in the MEE side chain contents and reached optima at F = 0.2−0.25. The best conductivity obtained is 2.2 × 10-5 S/cm for CPE-3A with F = 0.25.

Thermal analysis and characterization of 2-allylphenoxyorganocyclotriphosphazene copolymers

The radical copolymerizations of I (2-allylphenoxyorganocyclotriphosphazene) with chloride, phenoxy, 2,2,2-trifluoroethoxy side group reacting with II (styrene, methyl methacrylate and vinylbenzyl chloride) using AIBN, n-BuLi and ultraviolet as initiator were investigated. The type of the copolymerization, reaction time, temperature were evaluated to obtain the optimum reaction condition. The incorporation of organophosphazene units into an organic polymer backbone decreased the glass transition temperature and increased the thermal stability of the copolymers. The weight conversion and the molecular weight had a maximum value at reaction temperature of around 70 °C. The order for both weight conversion of the copolymerization and the thermal stability of phosphazene polymer with the co-monomer was VBC > STY > MMA, and with the side group Cl-> C6H5O-> CF3CH2O-. The phosphazene copolymer is of conductivity and crystallization.

Photochemical Behavior of Poly(Organophosphazenes). 15. Light-Induced Cross-Linking of [(4-Benzoylphenoxy)x(Methoxyethoxyethoxy)2 − x] Phosphazene Copolymers

The synthesis of a new, highly photosensitive, phosphazene copolymer containing an almost-equimolecular quantity of benzophenone and methoxyethoxyethoxy substituents is reported in this paper, together with the photochemical behavior of this material when irradiated in film both in oxygen and in an argon atmosphere. It has been detected that the photoreactivity of the phosphazene material strongly depends on the light absorption process by the benzophenone moieties, whose selective excitation predominantly brings about an intramolecular hydrogen abstraction reaction from the ethylene oxide units, thus producing highly reactive phosphazene macroradicals. The coupling reactions of these species results in the complete cross-linking of the polyphosphazene substrate and in its total insolubilization. Moreover, the influence of molecular oxygen on the overall photochemical process of the benzophenone/ethyleneoxide-substituted phosphazene copolymer is investigated. The implications of the light-induced reticulation process in the controlled insolubilization of poly[ bis (methoxyethoxyethoxy)phosphazene] are also discussed.

Functionalization of Poly(organophosphazenes). 8. Thermally-Induced Grafting Reactions of Maleates onto Poly[bis(4-ethylphenoxy)phosphazene

In this paper the radical-induced solution grafting of diethyl maleate onto poly[bis(4-ethylphenoxy)phosphazene] is reported, together with the possible parameters that can influence this reaction, i.e., the maleate, molecular oxygen, and dicumylperoxide concentration in the reaction mixture, the solvent, time, and temperature of the process. A possible mechanism of this process is inferred on the basis of literature data concerning analogous grafting processes carried out onto polyolefins. The importance of the decrease of the intrinsic viscosity of the reaction mixture that takes place during the grafting reaction is also discussed in terms of chain scission and molecular weight degradation of the phosphazene macromolecule. The possible implication of the final phosphazene copolymers containing variable quantities of grafted diethyl succinate groups, poly[bis(4-ethylphenoxy)phosphazene]-g-diethyl succinate, in blending processes with commercial, carbon-backboned macromolecules (polyesters and polycarbon...

Functionalization of poly(organophosphazenes)—V. Modification of the physico-chemical properties of poly[bis(4-methylphenoxy)phosphazene] through functionalization with anhydride groups

The radical-induced grafting reaction of maleic anhydride on to poly[bis(4-methylphenoxy)-phosphazene] is described and the different experimental parameters able to influence this process (maleic anhydride and peroxide concentrations, reaction time and temperature, molecular oxygen and solvent) are evaluated. The obtained poly[bis(4-methylphenoxy)phosphazene]-graft-succinic anhydride grafted copolymers show an enhanced reactivity toward air moisture, alcohols and amines with respect to the pristine phosphazene macromolecule. These substrates, in fact, are reacted with several organic substances containing free -OH and -NH 2 functionalities to obtain new functionalized phosphazene copolymers showing interesting scientific and technological potential.

Grafting reactions onto poly(organophosphazenes). IV. Light‐induced graft copolymerization of organic polymers containing free acid or basic functionalities onto poly[bis(4‐benzylphenoxy)phosphazene

AbstractThe light‐induced graft copolymerization of acrylic acid, methacrylic acid, and 4‐vinylpyridine onto poly[bis(4‐benzylphenoxy)phosphazene] films to prepare new grafted phosphazene copolymers containing acid and basic functionalities is reported. The process was carried out in monomer/methanol mixtures in the presence of benzophenone or benzoin ethyl ether as photosensitizers by selective excitation of these last species. The yield of the grafting processes was evaluated as a function of the monomer concentration in the reaction medium, type of photoinitiator, and characteristics of the grafted organic monomers. The acid functions inserted in poly[bis(4‐benzylphenoxy)phosphazene]‐g‐poly(meth)acrylic acid grafted copolymers, and the basic groups of the poly[bis(4‐benzylphenoxy)phosphazene]‐g‐poly‐4‐vinylpyridine substrates were allowed to interact with basic and acid dyes, respectively, to form permanently colored polymeric films. The photoactivity of these films as substrates for the photosensitized production of singlet oxygen was tested. © 1995 John Wiley & Sons, Inc.

Poly(organophosphazenes) containing azo dyes

AbstractIn this paper we describe a method for the functionalization of catenapoly[bis(4‐hydroxyphenoxy)‐λ5‐phosphazene] with diazonium salts to form new, deeply‐coloured, phosphazene copolymers containing variable amounts of azo dyes attached to the polyphosphazene skeleton. The degree of functionalization in these substrates is regulated in order not to exceed 20% of the sites available in the pristine polyphosphazene and to maintain a high percentage of unreacted, free, hydroxy groups, in the final, coloured copolymers. These species are still very reactive and able to undergo further functionalization reactions.

Physical properties of some organophosphazene copolymers. II. Thermoelasticity andin situ reinforcement of the cross-linked networks

Aryloxy phosphazene copolymers with phenoxy andp-ethyl phenoxy substituents were cross-linked into elastomeric networks and studied with regard to their stress-strain and thermoelastic (force-temperature) behavior. The thermoelastic results showed that the energetic contribution to the elastic force was negative, indicating that the unperturbed dimensions of the polymer chains decrease with increases in temperature.In situ precipitation of silica into the elastomers by hydrolysis of an absorbed alkoxysilane was found to give excellent network reinforcement.

Photochemical behavior of poly(organophosphazenes). X. Photo-cross-linking phenomena in poly[bis(4-isopropylphenoxy)0.8 (4-benzoylphenoxy)1.2 phosphazene

The synthesis and photochemical behavior both in solution and in the solid state of poly[bis(4-isopropylphenoxy)0.8 (4-benzoylphenoxy)1.2 phosphazene] is described. The main reaction of this material under illumination with light of a wavelength longer than 340 nm is the intramolecular abstraction of an hydrogen atom by the excited benzophenone substituent from the 4-isopropylphenoxy moiety geminally substituted on the same phosphorus of the phosphazene chain. In this way highly reactive radical species are produced which induce very efficient photo-cross-linking of the phosphazene copolymer and insolubilization. The efficiency of this process in the solid state is examined in view of the potential application of this material as a polyphosphazene-based negative photoresist.

Intramolecular naphthalene triplet excimers in solutions of phosphazene copolymers

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIntramolecular naphthalene triplet excimers in solutions of phosphazene copolymersLucia Flamigni, Nadia Camaioni, Pietro Bortolus, Francesco Minto, and Mario GleriaCite this: J. Phys. Chem. 1991, 95, 2, 971–975Publication Date (Print):January 1, 1991Publication History Published online1 May 2002Published inissue 1 January 1991https://doi.org/10.1021/j100155a087RIGHTS & PERMISSIONSArticle Views119Altmetric-Citations10LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (576 KB) Get e-Alerts

Synthesis and thermal properties of crosslinkable phosphazene copolymers

AbstractPolyphosphazenes of formula [NP(OC6H4CN)x(OCH2CF3)2−x] (x = 0.04–2) were prepared. The copolymers were crosslinked via cyclotrimerization of the nitrilic function, using acid catalysts (chlorosulfonic acid, aluminum chloride) at elevated temperatures. The thermal properties of the crosslinked cyclomatrix polymer were compared to the linear polymer by thermogravimetric analysis and differential scanning calorimetry. When the 4‐cyanophenoxy‐2,2,2‐trifluoroethoxy ratios were less than 0.2, the crosslinked polymers were soluble in polar organic solvents.