Phosphazene High Polymers Research Articles

Phosphazene High Polymers and Models with Cyclic Aliphatic Side Groups: New Structure–Property Relationships

Poly(dichlorophosphazene) is a versatile precursor material for accessing new polymeric materials via the introduction of various side groups by chlorine replacement reactions. Herein, methods are described for the synthesis of a new series of phosphazene single- and mixed-substituent high polymers containing cyclic aliphatic rings, −CnH2n–1 (where n = 4–8). These reactions were preceded by model reactions using small molecule cyclic trimeric phosphazenes. The new high polymers are amorphous, transparent, and film- and membrane-forming materials with a wide range of glass transition temperatures (−60 to +40 °C) depending on the side groups and cosubstituents. All are hydrophobic and resistant to hydrolytic breakdown.

Substituent Exchange Reactions of Linear Oligomeric Aryloxyphosphazenes with Sodium 2,2,2-Trifluoroethoxide

Side-group-exchange reactions have been studied for short-chain linear oligomeric phosphazenes, (RO)(4)P[N═P(OR(2))](n)OR (n = 6, 10, 20, and 40) as models for the corresponding linear high polymers (n ~ 15000). Specifically, the exchange behavior of oligomers where OR = OCH(2)CF(3), OC(6)H(5), OC(6)H(4)CHO-p, OC(6)H(4)CN-p, and OC(6)H(4)NO(2)-p with sodium trifluoroethoxide was examined. The ease of aryloxy group replacement by trifluoroethoxy increased with the electron-withdrawing character in the order OR = OC(6)H(5) ≪ OC(6)H(4)CHO-p < OC(6)H(4)CN-p < OC(6)H(4)NO(2)-p, but the reaction was efficient only if the phosphazene contained no more than 20 repeating units. However, attempts to force slower reactions by the use of excess sodium trifluoroethoxide induced secondary reactions at the trifluoroethoxy units already introduced to produce CF(3)CH(2)OCH(2)CF(3) and generate -O(-)Na(+) units in their place. The longest chain model underwent side-group-exchange reactions preferentially at the end units. These results are significant for the synthesis of phosphazene high polymers with fluoroalkoxy and aryloxy side groups.

ChemInform Abstract: Synthesis and Structure of Small-Molecule Cyclic Phosphazenes Bearing ortho-Substituted Aryloxy and Phenoxy Substituents.

A series of cyclic trimeric and tetramcric phosphazenes with ortho-substitutcd aryloxy side groups have been synthesized. The ortho substituents are methyl and phenyl groups. These compounds are structural models for the corresponding linear high-polymeric phosphazenes. X-ray structural analysis of the cyclic tetrameric species [NP(OC 6 H 4 CH 3 -2) 2 ] 4 (3), (NP(OC 6 H 4 C 6 -H 5 -2) 2 ] 4 (4) and [NP(OC 6 H 5 ) 2 ] 4 are reported

Small Molecule and High Polymeric Phosphazenes Containing Oxypyridine Side Groups and Their Organometallic Derivatives: Useful Precursors for Metal Nanostructured Materials

The pyridine-containing copolymers {[NP(O2C12H8)]X[NP(OC5H4N)2]1-X}n, with X = 0.7 (3a) and X = 0.8 (3b), and their respective organometallic derivatives of approximate formula {[NP(O2C12H8)]X[NP(OC5H4N·MLn)2]1-X}n with MLn = CpFe(dppe), CpRu(PPh2)2, (n5-CH3C5H4)Mn(CO)2, and W(CO)5 have been prepared and characterized. As models, the simple compounds N3P3(OC6H5)5OC5H4N·W(CO)5 (2) and HOC5H4N·W(CO)5 (1) have also been prepared and characterized. Pyrolysis of the organometallic polymers in air affords metallic nanostructured materials, which according to transmission electron microscopy (TEM), scanning electron microscopy (SEM), back-electron scattered imaging (BEI), energy-dispersive X-ray microanalysis, and micro-Raman data can be formulated as the coexistence of metal and metal oxide in the case of tungsten and as manganese phosphate salt in the case of manganese. A plausible formation mechanism is proposed, and the pyrolysis of the organometallic polyphosphazene polymer as a new and general method to obtain metallic nanostructured materials is discussed.

Hybrid Metallocene?Phosphazene Polymers

The incorporation of η6-arene, ferrocene, and ruthenocene side groups into phosphazene high polymers generates properties such as high melting behavior and electronic conductivity, and provides insights into reaction mechanisms and ring–polymer equilibria. The design and synthesis of these polymers is facilitated by model compound studies using small molecule cyclic phosphazenes.

THE CRUCIAL ROLE OF INORGANIC RING CHEMISTRY IN THE DEVELOPMENT OF NEW POLYMERS

The field of phosphazene high polymers has developed into a large area of more than 700 different types of macromolecules with novel combinations of properties and diverse applications. Small-molecule phosphazene rings have played a major role in these developments, first as starting materials for polymer synthesis, second as synthetic and structural models for the high polymers, and third as components of hybrid inorganic-organic macromolecules. These three aspects are reviewed, with examples taken from our recent work, together with some thoughts on the development of this and related fields in the future.

Langmuir−Adam Trough Studies of Hydrophobicity, Hydrophilicity, and Amphilicity in Small-Molecule and High-Polymeric Phosphazenes

Langmuir−Adam trough studies have been carried out to study the behavior of seven cyclic and linear short-chain small-molecule phosphazenes and four high polymers at air−water interfaces. The small-molecule compounds are models for a variety of phosphazene high polymers. The influence of phenoxy, 1,2-benzenedioxy, OCH2CF3, NH2, NEt2, NBu2, and OCH2CH2CH2CH2OCH3 side groups was studied. The air−water interface behavior of the small molecules depended on (a) the cyclic or linear skeletal structure and (b) the types of side groups linked to the ring or chain. The utilization of these results for understanding the behavior of phosphazene high polymers at air−water interfaces is discussed.

Preparation of a New Type of Phosphazene High Polymers Containing 2,2‘-Dioxybiphenyl Groups

The direct reaction of [NPCl2]n with the difunctional reagent 2,2‘-dihydroxybiphenyl (HOC6H4C6H4OH) and K2CO3 in tetrahydrofuran gave soluble linear phosphazene high polymers instead of the expected cross-linked products. The reaction of [N3P3Cl6] with 1, 2, or 3 equiv of HOC6H4C6H4OH and K2CO3 in acetone gave the known spiro derivatives [N3P3Cl4(O2C12H8)], [N3P3Cl2(O2C12H8)2], and [N3P3(O2C12H8)3] without formation of bridging products, and the dichloro derivative reacted directly with para-substituted phenols HOC6H4R and K2CO3 in acetone to give the new compounds [N3P3(OC6H4R)2(O2C12H8)2] (R = Br, COC6H5, or OCH3), without signs of replacement of the bis(aryloxy) substituents. In an analogous manner, poly(dichlorophosphazene) [NPCl2]n reacted with HOC6H4C6H4OH and K2CO3 in THF without significant cross-linking to give, depending on the mole ratio, the soluble polymer [NP(O2C12H8)]n (Mw = 450 000, Tg = 160 °C) or the partially substituted polymers {[NP(O2C12H8)]0.35[NPCl2]0.65}n. The latter were subseque...

Small-molecule model phosphazenes with para-substituted phenoxy side groups: synthesis, crystal structures and comparisons with corresponding high polymers

A series of new cyclic phosphazenes and a linear short-chain phosphazene have been synthesized as models for the preparation of the corresponding phosphazene high polymers. Several of the high polymers were also prepared. The small molecule compounds were characterized by a combination of 31P NMR, mass spectrometry and elemental analysis. The crystal and molecular structures of N3P3(OC6H4R-4)6(R = CH3, OH, OPh or OCH2Ph), N4P4(OC6H4OPh-4)8 and OP(OC6H4But-4)2NP(OC6H4 But-4) were investigated by single-crystal X-ray diffraction techniques. High polymers, [NP(OC6H4R-4)2]n, (R = OPh, OCH2Ph or But), [NP(OC6H4CPh3-4)1.5Cl0.5]n, and [NP(OCH2C6H4OCH2Ph-4)2]n were also prepared and their structures confirmed by a variety of techniques including 1H and 31P NMR spectroscopy, elemental analysis and differential scanning calorimetry.

Synthesis and structure of small-molecule phosphazene rings bearing fused-ring aryloxy side groups: models for optically useful high polymers

A series of cyclic tri- and tetra-metric phosphazenes [NP(OR)2]n(n= 3 or 4), N3P3(OR)Cl5 and N3P3(OR)4Cl2 has been prepared with 1- or 2-naphthyloxy, 1-naphthylmethyloxy, 1-naphthylethyloxy, 9-anthryloxy and 9-phenanthryloxy side groups OR. These syntheses are model processes for the preparation of the corresponding phosphazene high polymers. The small-molecule compounds were characterized by a combination of 31P NMR and mass spectroscopy, elemental analysis and crystal structures of six compounds. Attempts to synthesize the corresponding phosphazene high polymers by similar substitution techniques were, in general, successful, with high-temperature reaction conditions needed to overcome steric hindrance effects.

Molecular structures of cyclic mono- and di-(phosphoranylidene)aminophosphazenes: small-molecule models for high polymers

The molecular structures of four cyclic (phosphoranylidene)aminophosphazenes were determined. These compounds are small-molecule models for the corresponding high polymeric phosphazenes. The solid-state structures of gem-N3P3Cl4[NP(OPh)3]24, gem-N3P3(OPh)4[NP(OPh)3]25, N3P3(OPh)5NP(OPh)36 and N3P3(NHPr)5NP(NHPr)3·HCl 7 were determined by single crystal X-ray diffraction. Structural parameters: 4, triclinic, space group P, a= 12.900(2), b= 13.035(1), c= 14.349(6)A, α= 67.85(2), β= 80.68(3), γ= 67.73(1)°, Z= 2; 5, monoclinic, space group P21/n, a= 20.844(12), b= 13.679(3), c= 22.488(4)A, β= 116.91(3)°, Z= 4; 6, triclinic, space group P, a= 18.511(11), b= 23.206(26), c= 10.701(4)A, α= 98.67(5), β= 95.32(4), γ= 97.68(6)°, Z= 4 with two distinct molecular conformations; 7, triclinic, space group P, a= 13.187(10), b= 14.014(13), c= 14.335(4)A, α= 96.41(4), β= 115.76(5), γ= 115.12(5)°, Z= 2. Two interesting features of compound 7 are the presence of two long P–N bonds 1.686(9) and 1.676(8)A, and two narrowed N–P–N angles, 108.9(4) and 109.7(5)°, in the phosphazene ring.

Poly(monophosphazophosphazenes): New Polymers with N:PR3 Side Groups

Phosphazene high polymers with N=PR 3 (phosphazo) side groups were prepared with trifluoroethoxy, phenoxy, anilino, and propylamino side groups. Small-molecule cyclic counterparts were also synthesized as model systems for the macromolecular inactions. These compounds were prepared using both (trichlorophosphazo)pentachlorocyclotriphosphazene (N 3 P 3 Cl 5 NPCl 3 ) and (trichlorophosphazo)pentafluorocyclotriphosphazene (N 3 P 3 F 5 NPCl 3 ) as the starting materials. Specifically, the synthesis of monophosphazophosphazene polymers through the thermal ring-opening polymerization of N 3 P 3 Cl 5 NPCl 3 at 150-180°C or of N 3 P 3 F 5 NPCl 3 at 200-210°C is reported. Differences in the reactivity of the phosphazochloro- and the phosphazofluorophosphazenes to halogen replacement reactions were found at both the cyclic trimeric and high polymeric levels. In general, replacement of the chlorine atoms by organic groups was achieved with greater ease than the replacement of fluorine atoms. For the reagents studied, the replacement of halogen atoms by sodium trifluoroethoxide was more facile than with the other nucleophiles. A comparison is made between the properties of monophosphazophosphazenes, classical phosphazenes, and 1,1-diphosphazophosphazenes

Synthesis of Photo-Cross-Linkable Chalcone-Bearing Polyphosphazenes

Cyclic and high-polymeric phosphazenes that bear 4-(1-oxo-1-phenyl-2-propen-3-yl)phenoxy(4-oxychalcone) side groups have been prepared to study their photochemical behavior. Small-molecule cyclic trimers of the general formula N 3 P 3 R 5 R', where R= phenoxy, 2,2,2-trifluoroethoxy, chloro, and 4-oxychalcone and R'= 4-oxychalcone, were synthesized to model the cross-linking reactions at the high-polymer level. Single-substituent and cosubstituent polymeric phosphazenes [NPRR'] n , where R= phenoxy, 2,2,2-trifluoroethoxy, or 4-oxychalcone and R'= 4-oxychalcone were also prepared

Synthesis and Characterization of Photo-Cross-Linkable Small-Molecule and High-Polymeric Phosphazenes Bearing Cinnamate Groups

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and Characterization of Photo-Cross-Linkable Small-Molecule and High-Polymeric Phosphazenes Bearing Cinnamate GroupsHarry R. Allcock and Charles G. CameronCite this: Macromolecules 1994, 27, 12, 3125–3130Publication Date (Print):June 1, 1994Publication History Published online1 May 2002Published inissue 1 June 1994https://doi.org/10.1021/ma00090a002RIGHTS & PERMISSIONSArticle Views318Altmetric-Citations37LEARN 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 (768 KB) Get e-Alerts Get e-Alerts

Alkanesulfonation of cyclic and high polymeric phosphazenes

A method for sulfonating aminophosphazenes with the use of 1,3-propanesultone is described. The alkanesulfonation reactions were first developed with small molecule phosphazene cyclic trimers as models for high polymeric phosphazenes. High molecular weight poly(aminophosphazenes) were then sulfonated using similar techniques. This synthetic approach to sulfonated polymers is valuable for the development of new biomedical materials, membranes, reversibly cross-linkable polymers, surfactants, and polyelectrolytes

Phosphazene High Polymers; Molecular Design and the Role of Phosphorus iModern Polymer Chemistry

Abstract Molecular design and synthesis in phosphazene high polymers is discussed, with an emphasis on structure-property relationships

Synthesis and properties of high polymeric phosphazenes with (trimethylsilyl)methyl side groups

Poly(organophosphazenes) that bear Me 3 SiCH, side groups were prepared via the reaction of [(trimethysilyl)methyl]lithium with poly(phenylfluorophosphazene) ([NP(Ph)F(NPF 2 ) 2 ] n ). Fluorine replacement occurred under mild conditions to yield polymers that contained up to 70% of the side groups as alkasilyl units. Subsequent reaction with CF 3 CH 2 ONa gave air- and moisture-stable polymers with the basic stoichiometry of [NP(Ph) 0.34 (OCH 2 CF 3 ) 1.66-x (CH 2 SiMe 3 ) x ] n . Evidence was obtained that the organosilicon side groups are the sites of cross-linking reactions when the polymers are heated above 200°C

Synthesis and structure of small-molecule cyclic phosphazenes bearing ortho-substituted aryloxy and phenoxy substituents

A series of cyclic trimeric and tetramcric phosphazenes with ortho-substitutcd aryloxy side groups have been synthesized. The ortho substituents are methyl and phenyl groups. These compounds are structural models for the corresponding linear high-polymeric phosphazenes. X-ray structural analysis of the cyclic tetrameric species [NP(OC 6 H 4 CH 3 -2) 2 ] 4 (3), (NP(OC 6 H 4 C 6 -H 5 -2) 2 ] 4 (4) and [NP(OC 6 H 5 ) 2 ] 4 are reported

Synthesis and structure of borazinyl-substituted small-molecule and high polymeric phosphazenes: ceramic precursors

Synthesis and structure of borazinyl-substituted small-molecule and high polymeric phosphazenes: ceramic precursors

Antibacterial activity and mutagenicity studies of water-soluble phosphazene high polymers

Eight water-soluble phosphazene high polymers, [NPR 2] n ( R, organic, water-solubilizing side-group; n, approx: 15 000) and the small-molecule counterparts of the polymers were examined for antibacterial activity against six different strains of bacteria ( Escherichia coli, Salmonella typhimurium (TA 100), Salmonella pullorum, Streptococcus faecalis. Bacillus subtilis and Pseudomonas aeruginosa). Antibacterial testing was carried out by measuring zones of inhibition and changes in solution turbidity over time. In addition, the antibacterial activity of the surfaces of cross-linked poly[di(methoxyethoxyethoxy)phosphazene] (MEEP) hydrogels were investigated. A number of the high polymers, as well as the MEEP hydrogels, impeded bacterial growth. Only E. coli was unaffected by the phosphazenes. A possible explanation for the antibacterial character of the polymers is presented. The same compounds were monitored for potential mutagenic activity using the Salmonella typhimurium tester strains TA 100 and TA 98. None of the high polymers or their small-molecule analogues showed mutagenic activity in either strain of Salmonella at the concentrations tested. The use of these materials as coatings for artificial implants is discussed.