Crystal and molecular structure of hexamethylcyclotriphosphazene, (NPMe<sub>2</sub>)<sub>3</sub>

Oakley, Richard T.; Paddock, N. L.; Rettig, Steven J.; Trotter, James

doi:10.1139/v77-596

Cited by 21 publications

(11 citation statements)

References 12 publications

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“…As seen in Table , the SCF/3-21G* and MP2/3-21G* results do not differ significantly. Previous crystal structure analyses of [NP(R 2 )] 3 , where R = Me, F, Cl, and Br, are indicative of rings that are planar or very nearly so. − The optimized bond lengths, angles, and dihedrals (Table ) are similar to the values obtained previously by Ferris et al . at the SCF level of theory.…”

Section: Resultssupporting

confidence: 76%

Lubricants for Rigid Magnetic Media Based upon Cyclotriphosphazenes: Interactions with Lewis Acid Sites

1997

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Lubricants such as polyperfluorinated ethers are used topically on rigid magnetic media, or computer disks, to provide a low friction interface. These materials are subject to degradation particularly in the presence of Lewis acids; however, the degradation may in part be mitigated by the addition of additives such as bis(4-fluorophenoxy)tetrakis(3-(trifluoromethyl)phenoxy)cyclotriphosphazene, [(NP)3(OC6H4CF3)4(OC6H4F)2], or X-1P. This report explores how X-1P may preferentially interact with Lewis acid sites to impart protection to the host lubricant. Therefore, ab initio theoretical studies on the Lewis acid−base interactions between cyclotriphosphazene derivatives and AlF3 are performed. The theoretical results indicate that the strongest binding between X-1P and AlF3 is achieved when the endocyclic nitrogen atom bonds to the aluminum, providing a binding energy of the order of −55 kcal/mol. The magnitude of the binding energy indicates significant bonding as opposed to a dipole−dipole attraction. The lone pair of electrons on the phenoxy substituents also provide strong binding to AlF3, although not to the extent the nitrogen atoms do, with binding energies near −37 kcal/mol. Binding to fluorine is considerably smaller, near −8 kcal/mol. The population analyses indicate that the preferred nitrogen interaction involves the p-orbital that contains the in-plane lone pair of electrons. A computed reaction coordinate with [NPH2]3 and AlF3 gives every indication that the in-plane interaction is strongest and most stable on the potential energy surface. There is little desire on the part of the N3P3 ring itself to interact with Lewis acid sites parallel to the plane of the ring, i.e., with the p-orbitals housing the lone pair of electrons perpendicular to the plane of the ring. These orbitals instead provide weak π bonding with the phosphorus d-orbitals and are energetically well below the HOMO. The reason for the strong binding between AlF3 and the ring nitrogen atom originates from the polar, almost zwitterionic character of the endocyclic P−N bond, which polarizes the nitrogen atom negatively. All data lead to the conclusion that if the ring nitrogen in X-1P is sterically accessible, this will be the preferred binding site.

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Section: Resultssupporting

confidence: 76%

Lubricants for Rigid Magnetic Media Based upon Cyclotriphosphazenes: Interactions with Lewis Acid Sites

1997

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“…In general, the bond lengths in all the new nongeminal tetramer isomers are similar to closely related cyclic trimers and tetramers, (Me 2 PN) 3 , (Ph 2 PN) 3 , cis - and trans -[Ph(Me)PN] 3 , cis - and trans -[Ph(Et)PN] 3 , and (Me 2 PN) 4 . Average mean values of the PN bond lengths for 3 , 4 , 5 , and 6 are 1.596(8) Å, 1.594(3) Å, 1.588(5) Å, and 1.588(7) Å, respectively.…”

Section: Resultsmentioning

confidence: 66%

“…The Paryl distances for 3 [mean 1.814(2) Å], 4 [mean 1.816(3) Å], 5 [mean 1.810(9) Å], and 6 [mean 1.813(1) Å] are close to the typical Paryl distance of cis -[Ph(Me)PN] 3 [avg 1.811 Å], trans -[Ph(Me)PN] 3 [avg 1.807 Å], and (Ph 2 PN) 3 [avg 1.804 Å] . The Palkyl distances for 3 [mean 1.801(1) Å], 4 [mean 1.801(6) Å], 5 [mean 1.800(6) Å], and 6 [mean 1.798(3) Å] are also similar to other alkyl cyclics, (Me 2 PN) 3 [mean 1.810(10) Å], (Me 2 PN) 4 [avg 1.805(4) Å], cis -[Ph(Me)PN] 3 [mean 1.791(2) Å], trans -[Ph(Me)PN] 3 [mean 1.785(15) Å], cis -[Ph(Et)PN] 3 [mean 1.798(5) Å], and trans -[Ph(Et)PN] 3 [mean 1.81(1) Å] …”

Section: Resultsmentioning

confidence: 79%

Isolation and Characterization of Nongeminal Cyclic Methylphenylphosphazene Tetramers

et al. 2003

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Heating pure samples of the cyclic phosphazenes, cis- or trans-[Me(Ph)PN](3), yielded mixtures of the cis and trans isomers of the cyclic phosphazene trimers, [Me(Ph)PN](3), and all four geometric isomers of the tetramers, [Me(Ph)PN](4). Varying the temperature and heating times changes the ratio of these components. Following the thermolysis by NMR spectroscopy indicated that only a mixture of the two isomeric trimers occurred initially. Longer heating times produced mixtures of the isomers of the tetramer. Column chromatography and solubility differences were used to separate each of the isomers of the tetramer. Spectroscopic and X-ray crystallographic studies suggest that the four different geometrical isomers of the tetramer can be described as cone, partial cone, 1,2-alternate, and 1,3-alternate by analogy to calix[4]arene.

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“…The two molecules of 6 are conformers in which the two sulfur atoms, S(2) and S(5), display different geometries in the solid state. The mean P−N [ 3 , 1.596(8); 6 , 1.600(4) Å], P−aryl [ 3 , 1.805(5); 6 , 1.801(5) Å], and P−alkyl [ 3 , 1.811(5); 6 , 1.832(4) Å] distances are similar to cyclophosphazenes with P−C-bonded substituents, e.g., [Me(Ph)PN] 3 , (Ph 2 PN) 3 , (Me 2 PN) 3 , [Et(Ph)PN] 3 , and [XCH 2 (Ph)PN] 3 . The mean values of the P−N−P and N−P−N angles in 3 [122.2(7)° and 117.6(6)°] and 6 [122.2(5)° and 117.7(5)°] are also typical of cyclotriphosphazenes with P−C-bonded substituents. ,− Two of the C−P−C angles in 3 [103.7(9) and 105.3(33)] are typical of other simple cyclic alkylarylphosphazenes, , but like the halosubstituted PCH 2 X, compounds,9b the C(1)−P(1)−C(11) angle of 102.7° is slightly smaller.…”

Section: Resultsmentioning

confidence: 99%

“…The two molecules of 6 are conformers in which the two sulfur atoms, S(2) and S(5), display different geometries 6)°] and 6 [122.2(5)°and 117.7( 5)°] are also typical of cyclotriphosphazenes with P-C-bonded substituents. 9, [13][14][15][16] Two of the C-P-C angles in 3 [103.7(9) and 105. 3(33)] are typical of other simple cyclic alkylarylphosphazenes, 9,13 but like the halosubstituted PCH 2 X, compounds, 9b the C(1)-P(1)-C(11) angle of 102.7°is slightly smaller.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Characterization of Sulfur-Containing Nongeminal Cyclic and Polymeric Alkylarylphosphazenes

et al. 2005

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The methyl groups in both cyclic and polymeric methylphenylphosphazenes, [Me(Ph)PN]3 and [Me(Ph)PN]n, were modified using deprotonation-substitution and subsequent oxidation reactions to incorporate both thioether and sulfone functional groups. The new cyclic phosphazenes, cis-[Ph(RSCH2)-PN]3, 3 and 5, and cis-{Ph[RS(O)2CH2]PN}3, 6 and 7, where R ) Me or Ph, and the corresponding copolymers [Me(Ph)PN]x[Ph(RSCH2)PN]y, 8 and 9, and [Me(Ph)PN]x[{Ph[RS(O)2CH2]PN}y, 10 and 11, with varying ratios of x:y, were characterized by NMR and IR spectroscopy and thermal analysis.Crystallographic analysis of the cyclics 3 and 6 show that these molecules retain the basket shape of the nongeminal cis isomers with all the new functional groups opposite from the phenyl groups about the planar P3N3 ring. A cyclic trimer, cis-[Ph3(MeSCH2)2MeP3N3], 4, in which only two thioether groups had been incorporated was also isolated. The thioether-substituted polyphosphazenes, 8 and 9, were used as phase-transfer reagents and stabilizing hosts for the synthesis of gold nanoparticles. Analysis by UV spectroscopy and transmission electron microscopy indicated that the average gold particle size in these polymer nanocomposites was 3.2(0.9) nm. In solution, some aggregation of the nanoparticles was observed after one week, but the nanocomposites remain unchanged in the absence of solvent.

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Crystal and molecular structure of hexamethylcyclotriphosphazene, (NPMe₂)₃

Cited by 21 publications

References 12 publications

Lubricants for Rigid Magnetic Media Based upon Cyclotriphosphazenes: Interactions with Lewis Acid Sites

Lubricants for Rigid Magnetic Media Based upon Cyclotriphosphazenes: Interactions with Lewis Acid Sites

Isolation and Characterization of Nongeminal Cyclic Methylphenylphosphazene Tetramers

Synthesis and Characterization of Sulfur-Containing Nongeminal Cyclic and Polymeric Alkylarylphosphazenes

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Crystal and molecular structure of hexamethylcyclotriphosphazene, (NPMe2)3

Cited by 21 publications

References 12 publications

Lubricants for Rigid Magnetic Media Based upon Cyclotriphosphazenes: Interactions with Lewis Acid Sites

Lubricants for Rigid Magnetic Media Based upon Cyclotriphosphazenes: Interactions with Lewis Acid Sites

Isolation and Characterization of Nongeminal Cyclic Methylphenylphosphazene Tetramers

Synthesis and Characterization of Sulfur-Containing Nongeminal Cyclic and Polymeric Alkylarylphosphazenes

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Crystal and molecular structure of hexamethylcyclotriphosphazene, (NPMe₂)₃