Phosphazene Ring Research Articles

Copper(ii) chloride complexes with multimodal ligands based on the cyclotriphosphazene platform

The reaction of hexakis(2-pyridyloxy)cyclotriphosphazene (L) and hexakis(4-methyl-2-pyridyloxy)cyclotriphosphazene (MeL) with copper(ii) chloride afford the complexes [CuLCl(2)], [(CuCl(2))(2)(MeL)], [CuLCl]PF(6) and [Cu(MeL)Cl]PF(6). The single-crystal X-ray structure of [CuLCl(2)] shows the copper ion to be in a square based pyramidal distorted trigonal bipyramidal (SBPDTBP) environment (tau= 0.47) with L acting as a kappa(3)N donor, coordinating via the nitrogen atoms from two non-geminal pyridyloxy pendant arms, a nitrogen atom in the phosphazene ring and two chloride ions. In the dimetallic complex, [(CuCl(2))(2)(MeL)], the geometry about both (symmetry related) copper(ii) centres is also SBPDTBP (tau= 0.57) with a 'N(3)Cl(2)' donor set. In the monocation of [CuLCl]PF(6), L acts as a kappa(5)N donor, bonding to the copper(ii) centre through the nitrogen atoms of four pyridyloxy pendant arms, a phosphazene ring nitrogen atom and a chloride ion to give an elongated rhombic octahedral coordination sphere. The phosphazene ring atoms remain virtually coplanar in all three structures as a consequence of the phenoxy-hinge, which links the pyridine pendant donors to the cyclotriphosphazene platform, allowing the formation of six-membered chelate rings. The spectroscopic (mass spectral, EPR and electronic) and magnetic properties of the complexes are discussed. The EPR and variable temperature magnetic susceptibility results for the dicopper complex, [(CuCl(2))(2)(MeL)], point to a very weak electronic interaction between the metal atoms.

Crystal Structure of 4',4',6',6'-Tetrapyrrolidino-spiro{1,3,2[1,2-ethanedioxy bis(2-phenylamino)phosphorine-2,2'.LAMBDA.5-[4.LAMBDA.5,6.LAMBDA.5] [1,3,5,2,4,6]-triazatriphosphorine

The title ligand, C30H46N9O2P3, is a cyclophosphazenic lariat (PNP pivot) ether with a spiro-cyclic 11-membered macrocyclic ring, containing two N and two ether O atoms, and four pyrrolidino rings; the phosphazene ring is not planar. It belongs to the space group P21/n with cell parameters a = 9.2134(8), b = 9.826(3), c = 36.150(4)A and β = 90.097(9)°. The macrocyclic ring contains a three-centered (bifurcate) N-H…O hydrogen bond, and the relative inner-hole size (radius) of the macroring is ∼1.16 A.

A Spirocyclic System Comprising Both Phosphazane and Phosphazene Rings

The reaction of hexakis(cyclohexylamino) cyclotriphosphazene [NP(CyNH)(2)](3), 1, with phosphorus trichloride yields [NP(CyN)(2)PCl](3), 2, which contains three four-membered phosphazane rings fused in spirocyclic fashion to a central six-membered phosphazene ring and constitutes the first structurally characterized compound that comprises both phosphazene and phosphazane rings. The peripheral P atoms feature stereoactive lone pairs, and, thus, 2 exists in isomeric C(3h) and C(s) forms. The spirocyclic phosphazene-phosphazane derivative 2 carries three reactive PCl functions in peripheral positions, promising an interesting precursor molecule for the synthesis of extended phosphorus nitrogen structures of high rigidity. Extension of the PN moiety can be achieved by reaction of 2 with a primary amine yielding [NP(CyN)(2)PN(H)(t)Bu](3), 3, which features a central scaffold of 6 phosphorus and 12 nitrogen centers and aggregates via N-H...P hydrogen bonds in the solid state. On the contrary, the reaction of 1 with SbCl(3) undergoes incomplete proton abstraction, resulting in the formation of the tricyclic compound N(3)P(3)(CyNH)(4)(CyNSbCl(2))(2), 4, which contains two four-coordinate Sb centers chelated by N(exo)-N(ring) sites of the phosphazene.

Phosphorus–nitrogen compounds: novel spiro-crypta-phosphazenes. Structure of {pentane-3-oxa- N, N′- bis(1,5-oxybenzyl)- spiro (propane-1′,3′-diamino)-4,4,6,6-tetrachlorocyclo- 2λ 5,4λ 5,6λ 5-triphosphazatriene}. Part IX

The condensation reactions between hexachlorocyclotriphosphazatriene ( 1), N 3P 3Cl 6, and dibenzo-diaza crown ethers ( 2 and 3) afforded two novel spiro-crypta-phosphazene derivatives ( 4 and 5). Compounds ( 4 and 5) have been characterized by elemental analyses, FTIR, 1H-, 13C-, 31P NMR, HETCOR and MS. The structure of crypta-phosphazene ( 5) has been determined crystallographically. Compounds ( 4 and 5) are the first examples of the crypta-phosphazene derivatives. The 31P NMR spectra of compounds ( 4 and 5) indicate that both of the compounds have anisochrony, possibly because of the stereogenic nitrogen atoms. In compound ( 5), the pyramidal geometries of four spiro-cyclic nitrogen atoms give rise to stereogenic properties. The sum of the bond angles around N4, N4A, N5 and N5A nitrogens are 346.2(4), 348.8(3), 347.1(3) and 345.8(4)°, respectively. Compound ( 5) crystallizes in the P2 1 space group with a=11.831(2), b=21.108(2), c=11.936(1) Å, β=102.70(1)°, V=2907.9(6) Å 3, Z=2 and D x =1.442 g cm −3. The absolute structure was determined successfully. There are two molecules in the asymmetric unit. The structure consists of a non-centrosymmetric, non-planar phosphazene ring with a bulky dibenzo-diaza crown ether side group.

4',4',6',6'-Tetrachloro-3,4-dihydro-3-(6-methylpyridin-2-yl)spiro[1,3,2-benzoxazaphosphinine-2,2'-(2lambda5,4lambda5,6lambda5-cyclotriphosphazene)

The title compound, C13H12Cl4N5OP3, is a phosphazene derivative with a bulky substituted spirocyclic ring. The C3NPO spirocyclic ring has a twist-boat conformation, while the phosphazene ring has a very flattened boat conformation.

Phosphazene-based ionic liquids: synthesis, temperature-dependent viscosity, and effect as additives in water lubrication of silicon nitride ceramics.

Phosphazene rings with (dimethylamino)ethoxy (1, 2), pyridylmethoxy (3), or (dimethylamino)propoxy (4) chains were synthesized and quaternized at the substitutent nitrogen by treatment with methyl iodide at 35 degrees C over 3-6 h to give polyiodo salts, 5-8. Subsequent metathesis with LiN(SO(2)CF(3))(2) or NaBF(4) gave the respective ionic salts, 9-13. The amide salts, 9-12, were viscous liquids with pour points at 55-100 degrees C, and the tetrafluoroborate salt, 13, was a solid, mp 168 degrees C. The compositions of 2 and 5-13 were confirmed by elemental analysis and spectroscopic methods. Compounds 1, 2, and 4 were viscous liquids (d(25) = 1.67 g cm(-3); eta(25) = 0.76-1.56 mPa s(-1) ) with pour points at approximately 15 degrees C. The solid polyquaternary salts, 5-8, melted at 130-194 degrees C. The ionic liquids, 9-12, had an average density of approximately 1.73 g cm(-3) at 25 degrees C, and viscosities (25 degrees C) ranged between 68.3 and 139.2 mPa s(-1). A plot of the viscosities of 9-12 vs temperature revealed an almost linear correlation between 55 and 120 degrees C. Friction and wear properties of water with 0.25 wt % of 9-12 as boundary lubricant additives were evaluated on Si(3)N(4)/Si(3)N(4) ceramic interfaces. The most significant observation is that they caused a decrease in the running-in period.

4,4,6,6-Tetrachloro-2,2-(ethylenedioxydi-o-phenylenediimino)-2lambda5,4lambda5,6lambda5-cyclotriphosphazene.

The title ligand, C14H14Cl4N5O2P3, is a cyclophosphazene lariat (PNP pivot) ether with a spiro-cyclic 11-membered macrocyclic ring containing two ether O and two N atoms; the phosphazene ring is nearly planar. The macrocyclic ring contains a four-centred (trifurcate) N-H...O/N-H...N hydrogen bond, and the relative inner-hole size of the macrocycle is approximately 1.14 A in radius. The molecules are linked about inversion centres by N-H...N hydrogen bonds into centrosymmetric dimers.

Phosphorus–nitrogen compounds. spiro- and crypta-phosphazene derivatives: synthesis and spectral investigations. Structure of butane- N, N′-bis(1,4-oxybenzyl)- spiro(propane-1,3-diamino)tetrachlorocyclo-2λ 5, 4λ 5, 6λ 5-triphosphazatriene. Part VII

The condensation reactions between trimer, N 3P 3Cl 6, and diamines, 2 and 4 and {1-{ N-[1-(2-hydroxynaphthylmethyl)aminomethylidene]}-2(1H)-naphthalenone, 3, yielded the new spiro-cyclic- ( 5 and 8) and the novel spiro-phosphazene ( 7) derivatives, respectively. The fully substituted phosphazene ( 6) was also obtained from the reaction of 5 with the excess of pyrrolidine. Compounds ( 4– 8) have been characterized by elemental analyses, FTIR, 1H-, 13C-, 31P-NMR, HETCOR, COSY and MS. The structure of crypta-phosphazene, 8, has been examined crystallographically. Compound 8 is the first example of the crypta-phosphazene derivatives. The 31P-NMR spectra of compounds 7 and 8 indicate that, both of the compounds have anisochronism because of the stereogenic centers. The pyramidal geometry of two spiro-cyclic nitrogen atoms in compound 8, gives rise to stereogenic property. The sums of the bond angles around N 4 and N 5 nitrogens are 350.6(2) and 349.6(3)°, respectively. Compound 8 crystallizes in the triclinic space group P 1 with a=8.798(3), b=10.498(3) and c=15.689(4) Å; α=91.35(2), β=103.39(4) and γ=102.88(4)°; V=1369.9(7) Å 3, Z=2 and D x=1.491 g cm −3. It consists of a non-centrosymmetric, non-planar phosphazene ring with a bulky dibenzo-diazacrown etheric side group.

4,4,6,6-Tetrachloro-2,2-(propylenedioxydi-o-phenylenediimino)-2lambda5,4lambda5,6lambda5-cyclotriphosphazene.

The title compound, C(15)H(16)Cl(4)N(5)O(2)P(3), is a cyclophosphazenic lariat (PNP-pivot) ether with a spiro-cyclic 12-membered macrocyclic ligand containing two ether O and two N atoms; the phosphazene ring is nearly planar. In the macrocyclic ring, there is a four-center (trifurcate) N-H.O/N-H.N hydrogen bond. The relative inner-hole size of the macrocycle is estimated as approximately 0.95 A.

Phosphorus?nitrogen compounds. spiro- and crypta-phosphazene derivatives: synthesis and spectral investigations. Structure of butane-N,N$prime;-bis(1,4-oxybenzyl)-spiro(propane-1,3-diamino)tetrachlorocyclo-2$lambda;5, 4$lambda;5, 6$lambda;5-triphosphazatriene. Part VII

The condensation reactions between trimer, N3P3Cl6, and diamines, 2 and 4 and {1-{N-[1-(2-hydroxynaphthylmethyl)aminomethylidene]}-2(1H)-naphthalenone, 3, yielded the new spiro-cyclic- (5 and 8) and the novel spiro-phosphazene (7) derivatives, respectively. The fully substituted phosphazene (6) was also obtained from the reaction of 5 with the excess of pyrrolidine. Compounds (4–8) have been characterized by elemental analyses, FTIR, 1H-, 13C-, 31P-NMR, HETCOR, COSY and MS. The structure of crypta-phosphazene, 8, has been examined crystallographically. Compound 8 is the first example of the crypta-phosphazene derivatives. The 31P-NMR spectra of compounds 7 and 8 indicate that, both of the compounds have anisochronism because of the stereogenic centers. The pyramidal geometry of two spiro-cyclic nitrogen atoms in compound 8, gives rise to stereogenic property. The sums of the bond angles around N4 and N5 nitrogens are 350.6(2) and 349.6(3)°, respectively. Compound 8 crystallizes in the triclinic space group P1 with a=8.798(3), b=10.498(3) and c=15.689(4) Å; α=91.35(2), β=103.39(4) and γ=102.88(4)°; V=1369.9(7) Å3, Z=2 and Dx=1.491gcm−3. It consists of a non-centrosymmetric, non-planar phosphazene ring with a bulky dibenzo-diazacrown etheric side group.

SYNTHESIS AND POLYMERIZATION OF MULTIFUNCTIONAL CYCLOPHOSPHAZENES

It has been found that the variety of new and useful cyclotriphosphazene derivatives that are available by nucleophilic displacement of halogens on the phosphazene ring can be expanded dramatically...

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.

Cyclophosphazenes as nodal ligands in coordination polymers.

Herein, we show that cyclotriphosphazenes carrying organo amino side chains, (RNH)6P3N3 [R = n-propyl (1), cyclohexyl (2), benzyl (3)], and (C4H8N)6P3N3 (4) produce supramolecular coordination compounds in conjunction with silver salts by formation of linear N-Ag-N connections via nitrogen centers of the phosphazene ring. Crystalline materials were obtained by layering methanol solutions containing phosphazene ligands with methanol solutions of AgClO4 and AgNO3. The donor ability of the anion and the steric demand of the lipophilic ligand sphere R control the topology of the coordination network: (1)2(AgClO4)3 forms a graphite-type (6,3) network. All three N(ring) atoms of the phosphazene ligand coordinate to silver ions, which, in return, linearly bridge two phosphazene ligands. The phosphazene-Ag(I) arrangement in 1(AgNO3)2 exists of zigzag chains featuring one bridging silver ion and one terminally coordinated silver ion per ligand molecule. The terminally located Ag(I) ions of neighboring chains are bridged by nitrate ions, resulting in a 2D network. Both 2(AgClO4) and 4(AgClO4) contain only one bridging silver ion per phosphazene ligand, which leaves one N(ring) site vacant and gives 1D zigzag chain arrangements. The crystal structures of 3(AgClO4)2 and 3(AgNO3)2 resemble that of 1(AgNO3)2, but show additional Ag-pi(aryl) interactions between the terminally arranged silver ions and benzyl groups. Treatment of 3 with a methanol solution containing both AgNO3 and AgClO4 leads to the heteroanion derivative 3(AgNO3)(AgClO4). Phosphazene ligands 1-3 have the ability to undergo hydrogen bonding to anions via the six NH groups, and the coordination polymers containing these ligands feature dense networks of NH...O bonds.

Enhancement of thermal stability of polystyrene and poly(methyl methacrylate) by cyclotriphosphazene derivatives

The thermal stability and degradation behavior of polystyrene (PSt) and poly(methyl methacrylate) (PMMA) blended with organic cyclotriphosphazenes (N 3P 3(OR) 6) were investigated by thermogravimetric analysis and gel permeation chromatography. The thermal degradation behaviors of polymers are strongly dependent on the organic groups attached to the phosphazene ring (R: S-4,-C 6H 3(-OCH 2O-); S-5,-C 6H 4CH 2OPO(OPh) 2; S-6,-C 6H 4OPO(OPh) 2; S-7,-C 6H 4OCH 2OCH 3). The onset temperature of decomposition ( T 0) of PSt increased from 303 °C to 351 °C in air by the addition of 5 wt.% S-4, whereas S-6 has no ability to increase T 0 value of PSt. The GPC traces of PSt/ S-4 film heated at 180 °C for 30 min in air showed no significant decrease of molecular weight of PSt. A similar enhancement of thermal stability was observed for the PMMA/ S-4 system. From the reaction of radical initiators with S-4, it appears that –OCH 2O– group in S-4 acts as an effective trapping site of peroxy radical. As expected, the physical loss of S-4 with molecular weight increased by using cyclotriphosphazene core from PSt film was significantly suppressed, i.e., the diffusion coefficient of S-4 was three orders of magnitude smaller than that of 3,4-methylenedioxyphenol ( MOP). The enhancement of thermal stability of PSt and PMMA blended with cyclotriphosphazene derivatives were described.

Synthesis, characterization, and thermal stability of star-shaped poly(ε-caprolactone) with phosphazene core

Hexakis[ p-(hydroxylmethyl)phenoxy]cyclotriphosphazene was synthesized by the reaction of hexachlorocyclotriphosphazene with the sodium salt of 4-hydroxybenzaldehyde and subsequent reduction of aldehyde groups to alcohol groups by using sodium borohydride. This compound was employed in initiating the ring-opening polymerization of ε-caprolactone. The resulting polymers were characterized using Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), and gel permeation chromatography (GPC). The characterization data indicated the star-shaped PCL with phosphazene core were successfully synthesized with narrow molecular weight distribution and high yields. 1H-NMR analysis was used to calculate the number-average molecular weight. The calculated result from NMR was closer to the theoretical data than that from GPC analysis. Polarizing optical microscopy (POM) combined with differential scanning calorimetry (DSC) was used to study the crystallization behavior of the star-shaped PCL. The result indicated that the highly branched architecture of star-shaped PCL resulted in interrupted crystallization form and subsequently lower melting temperature. Thermogravimetric analysis (TGA) carried out on the star-shaped PCL suggested that introduction of phosphazene rings strengthen the thermal stability of the resulting polymers.

Phosphorus–nitrogen compounds. Part VI. Aminolysis of octachlorocyclotetraphosphazatetraene and the crystal structure of 2- trans-6-bis(n-propylamino)-2,4,4,6,8,8-hexakis- tert-butylaminocyclo-2λ 5, 4λ 5, 6λ 5, 8λ 5-tetraphosphazatetraene

The reactions of 2- trans-6-N 4P 4(NHPr n ) 2Cl 6 ( 2), which was obtained from N 4P 4Cl 8 ( 1) and n-propylamine, with pyrrolidine and t-butylamine in different solvents have been studied. Compound ( 2) gave two different products, namely monocyclic ( 3 and 5) and bicyclic ( 4 and 6) phosphazenes. Compounds ( 2– 6) have been characterized by elemental analysis, IR, 1H-, 13C-, 31P NMR, HETCOR and MS and the structure of compound ( 5) has been examined crystallographically. The bicyclic phosphazene ( 6) is the first exciting example of bicyclic phosphazenes containing chlorine atoms, in the literature. The formation mechanisms of bicyclic phosphazenes are re-considered by taking into account the synthesis of compound ( 6), which contains three stereogenic phosphorus atoms. Compound ( 5) crystallizes in the monocyclic space group P2 1/ n with a=13.974(2), b=17.836(5), and c=18.683(4) Å, β=98.50(1)°, V=4605.4(2) Å 3, Z=4 and D x =1.051 g cm −3. It consists of a non-centrosymmetric, non-planar phosphazene ring in a saddle conformation, with two n-propylamino (in 2- trans-6 positions) and six bulky t-butylamino side groups. The bulky substituents are instrumental in determining the molecular geometry.

Synthesis and antitumor activity of novel thermosensitive platinum(II)–cyclotriphosphazene conjugates

Thermosensitive cyclotriphosphazenes bearing alkoxy poly(ethylene glycol) and amino acid esters as side groups could be functionalized to chelate the antitumor (diamine)platinum(II) moiety through the dicarboxylate group of the amino acid substituent on the cyclic phosphazene ring. Surprisingly, like the precursor cyclotriphosphazenes, these (diamine)platinum(II)–cyclotriphosphazene conjugates were also found to exhibit variable lower critical solution temperatures (LCST) in the wide range of 12 to 92 °C. Furthermore, the present conjugates have shown outstanding in vitro and in vivo antitumor activities due to controlled release of the antitumor (diamine)platinum(II) moiety with hydrolytic degradation of the phosphazene ring. A few of these conjugates have shown LCSTs below body temperature, and it has been shown from a model animal experiment that the conjugates with a LCST below body temperature may be applied to local drug delivery by direct intratumoral injection.

Synthesis and ansa substitution of novel examples of aryl hydrido fluorophosphazenes

The first examples of uncharged aryl substituted fluorinated hydridophosphazenes, N 3P 3F 4(Ar)H [Ar=C 6H 5 ( 1), p-ClC 6H 4 ( 2)] were obtained in an unprecedented manner upon fluorination of diaryloctachlorobi(cyclophosphazenes) (N 6P 6Cl 8(Ar) 2) [Ar=C 6H 5, p-ClC 6H 4] using KF in acetonitrile. The compounds ( 1) and ( 2) were stable to air and moisture, and were characterized by spectral and analytical methods. Compound ( 1) on reaction with FcCH 2P(S)(CH 2OLi) 2 (Fc=Ferrocenyl) gave endo ( 3) and exo ( 4) isomers of ansa substituted hydridophosphazenes. The crystal structure of ( 4) was determined and the structure shows the ansa substitution on the phosphazene ring, trans to the phenyl group with the hydridophosphazene ring puckered to a partial chair configuration.

Mesogenicity of Organophosphazenes: The Effect of Phosphazene Rings and Side Groups on the Phase Transition

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis and Conformation of Star‐Shaped Poly(γ‐benzyl‐L‐glutamate)s on a Cyclotriphosphazene Core

AbstractThe preparation of star‐shaped poly(γ‐benzyl‐L‐glutamate)s by the ring‐opening polymerization of N‐carboxy anhydride γ‐benzyl‐L‐glutamate (BLG‐NCA) with hexakis(4‐aminomethylphenoxy)‐ (4) and hexakis(4‐aminophenoxy)cyclotriphosphazenes (6), and the conformation of resulting polymers has been studied. The six amino groups in 4 can initiate the polymerization of BLG‐NCA to give star‐shaped polyglutamates (7) with narrow molecular weight distributions (Mw/Mn = 1.10–1.33). For the polymerization of BLG‐NCA with 6, however, a high ratio of [BLG‐MCA]/[6] was required to obtain star‐shaped polyglutamates (8). The conformation of 7 changed from a β‐sheet form to a right‐handed α‐helix form, depending on the degree of polymerization per chain (DPn/6). The helix content of hexa‐armed poly (γ‐benzyl‐L‐glutamate‐co‐L‐glutamic acid)s (9), prepared by partial hydrolysis of 7, increased significantly compared with that of the corresponding linear analogue (10). As increasing of helix content of 9, the fluorescence spectra of 8‐anilino‐1‐naphthalenesulfonic acid (ANS), a fluorescence probe, shifted to a short wavelength accompanied by the enhancement of intensity, suggesting that star‐shaped polymers are liable to form hydrophobic domains. From these results and the structural feature of the cyclotriphosphazene core, the formation of a 3α‐helix bundle structure of polyglutamates on both sides of the phosphazene ring has been suggested. magnified image