Phosphazenes and Surfaces

Gleria, Mario; Milani, Roberto; Bertani, Roberta; Boscoletto, A. Boscolo; Jaeger, Roger De

doi:10.1002/9780470478882.ch12

Cited by 33 publications

(48 citation statements)

References 125 publications

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“…In principle, as found in several deriva- [29] the two diastereoisomers could be distinguished by NMR spectroscopy. For 2 Cl 2 ], however, the occurrence of interconversion processes between stereoisomers, which involved a change of chirality at the 2,2'-dioxybiphenyl groups via an intermediate with a planar sevenmembered ring at phosphorus, was shown by variable-temperature NMR spectroscopy studies combined with molecular dynamics simulations. [30] Furthermore, it was indicated that in the solid-state noncovalent p-p stacking interactions between dioxybiphenyl groups are effective in the formation of an ordered polymer-like assembly due to the enantiomeric discrimination between the R and S moieties of the meso molecules.…”

Section: Introductionmentioning

confidence: 97%

“…[1c, 2] We have recently contributed to this field A C H T U N G T R E N N U N G PPh 3 (P2)). All complexes have been characterized by elemental analysis, various spectroscopic methods, and mass spectrometry.…”

Section: Introductionmentioning

confidence: 99%

“…[12] Results and Discussion Synthesis and characterization of cyclic trimeric systems: A cyclotriphosphazene bearing two 4-oxypyridine groups, gem- 2 ], was reacted, in dichloromethane, with the gold or silver complexes…”

Section: Introductionmentioning

confidence: 99%

“…The starting cyclotriphosphazene (I) was prepared as previously described, [21] starting from gem-[N 3 P 3 - 2 Cl 2 ], which was prepared in turn from hexachlorocyclotriphosphazene, [N 3 P 3 Cl 6 ]. The complexes 1-5 are soluble in dichloromethane and insoluble in hexane or pentane.…”

Section: Introductionmentioning

confidence: 99%

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Metallocyclo‐ and Polyphosphazenes Containing Gold or Silver: Thermolytic Transformation into Nanostructured Materials

Jiménez

Laguna

Benouazzane

et al. 2009

Chemistry A European J

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A cyclotriphosphazene bearing two 4-oxypyridine groups on the same phosphorus atom, gem-[N(3)P(3)(O(2)C(12)H(8))(2)(OC(5)H(4)N-4)(2)] (I), and its analogous polymer [{NP(O(2)C(12)H(8))}(0.7){NP(OC(5)H(4)N-4)(2)}(0.3)](n) (II), have been used to prepare gold or silver, cyclic and polymeric, metallophosphazenes. The following complexes, gem-[N(3)P(3)(O(2)C(12)H(8))(2)(OC(5)H(4)N-4{ML})(2)] (ML=Au(C(6)F(5)) (1) or Au(C(6)F(5))(3) (2)), [N(3)P(3)(O(2)C(12)H(8))(2)(OC(5)H(4)N-4{AuPPh(3)})(2)][NO(3)](2) (3), and [N(3)P(3)(O(2)C(12)H(8))(2)(OC(5)H(4)N-4{AgPPh(2)R})(2)][SO(3)CF(3)](2) (R=Ph (4) or Me (5)) have been obtained. Complexes 1 and 4 are excellent models for the preparation of the analogous polymers [{NP(O(2)C(12)H(8))}(0.7){NP(OC(5)H(4)N-4{ML})(2)}(0.3)](n) (ML=Au(C(6)F(5)) (P1), Ag(OSO(2)CF(3))PPh(3) (P2)). All complexes have been characterized by elemental analysis, various spectroscopic methods, and mass spectrometry. The polymers were further investigated by thermochemical methods (thermogravimetric analysis) and differential scanning calorimetry. For compounds 1-5 and for the starting phosphazene I, a mixture of different stereoisomers may be expected. The stereochemistry in solution has been studied by variable-temperature NMR spectroscopy studies, which provided evidence for interconversion processes that involve changes in the chirality of a 2,2'-dioxybiphenyl group. A single-crystal X-ray analysis of the gold complex 2 confirmed not only the proposed structure, but also S,S and R,R configurations at the two biphenoxy-substituted phosphorus centers, in contrast to those observed for the precursor I. Pyrolysis of these new metallophosphazenes was also studied. Notably, pyrolysis of the gold derivatives gave macroporous metallic gold sponges without the requirement of either an external reducing agent or a porous support. These materials were all characterized by XRD, TEM, SEM, and energy-dispersive X-ray spectroscopy.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Metallocyclo‐ and Polyphosphazenes Containing Gold or Silver: Thermolytic Transformation into Nanostructured Materials

Jiménez

Laguna

Benouazzane

et al. 2009

Chemistry A European J

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“…Most studies on the cyclotriphosphazene focused on ring opening polymerization of the cyclotriphosphazene ring. 16,17 With the exception of polymerization research, cyclophosphazene derivatives have been examined as potential flame retardant materials, [18][19][20][21][22][23][24] lubricants, 25 and star polymers.…”

Section: -12mentioning

confidence: 99%

Preparation and Characterization of Vesicles Using Octasubstituted Cyclotetraphosphazene

Shin¹,

Park²,

Lee³

et al. 2008

Bulletin of the Korean Chemical Society

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A cyclotetraphosphazene derivative with eight chains was synthesized from octachlorocyclotetraphosphazene. The vesicles were prepared using the cyclotetraphosphazene derivative and cholesterol. The resulting vesicles were characterized by TEM and measurements of their encapsulation efficiency. The stability of the vesicles was enhanced with the addition of dihexadecylphosphate. The size and the encapsulation efficiency of the vesicles changed according to the amount of cholesterol added. The size and the encapsulation efficiency of the vesicle were lowest when the mole ratio (cholesterol: the cyclophosphazene derivative) was 0.9.

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Electronic Structure of N₂P₂ Four‐Membered Rings

2014

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The biradicaloid character of the ground‐state structures of N2P2 rings is studied by using the high‐level ab initio multiconfigurational CASPT2/CASSCF method. In order to obtain accurate descriptors, we combine two criteria: 1) singlet–triplet energy gaps and 2) relative values of the occupation numbers for bonding and antibonding orbitals associated with the radical sites. The singlet–triplet energy gaps, the occupation numbers of antibonding‐like orbitals, and the weights of the main configuration state functions (CSFs) of the ground‐state wavefunctions, that is, Ψ(1A1), are used to derive the biradicaloid character that ranges from 10–15 %.

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Phosphazenes and Surfaces

Cited by 33 publications

References 125 publications

Metallocyclo‐ and Polyphosphazenes Containing Gold or Silver: Thermolytic Transformation into Nanostructured Materials

Metallocyclo‐ and Polyphosphazenes Containing Gold or Silver: Thermolytic Transformation into Nanostructured Materials

Preparation and Characterization of Vesicles Using Octasubstituted Cyclotetraphosphazene

Electronic Structure of N₂P₂ Four‐Membered Rings

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Phosphazenes and Surfaces

Cited by 33 publications

References 125 publications

Metallocyclo‐ and Polyphosphazenes Containing Gold or Silver: Thermolytic Transformation into Nanostructured Materials

Metallocyclo‐ and Polyphosphazenes Containing Gold or Silver: Thermolytic Transformation into Nanostructured Materials

Preparation and Characterization of Vesicles Using Octasubstituted Cyclotetraphosphazene

Electronic Structure of N2P2 Four‐Membered Rings

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Electronic Structure of N₂P₂ Four‐Membered Rings