Whose Side Are You On?

The cyclophosphazene hydrazides N3P3(N(Me)NH2)6 (1), spiro-N3P3(C12H8O2)(N(Me)NH2)4 (2), and dispiro-N3P3(C12H8O2)2(N(Me)NH2)2 (3) have been readily elaborated by a click synthesis involving condensation with pentafluorobenzaldehyde to afford the fluorine-rich cyclophosphazene hydrazones N3P3(N(Me)N=CHC6F5)6 (4), spiro-N3P3(C12H8O2)(N(Me)N=CHC6F5)4 (5), and dispiro-N3P3(C12H8O2)2(N(Me)N=CHC6F5)2 (6) in excellent yields. The molecular and crystal structures of 4-6 are reported. The crystal structures of 4-6 reveal a rich interplay of various intermolecular secondary interactions generating novel supramolecular architectures. The dependence of the molecular symmetry on the eventual supramolecular structures is also revealed. The crystal structure of 6 shows the selective entrapment of guest dioxane molecules

Hybrid polymeric ligands and polymer supported catalysts containing cyclophosphazenes

Reaction of N3P3Cl6 with HO-C6H4-p-C6H4-p-CH=CH2 affords N3P3Cl5O-C6H4-p-C6H4-p-CH=CH2 (1). Compound 1 reacts with 3,5-dimethylpyrazole to afford N3P3(3,5-Me2Pz)5(O-C6H4-p-C6H4-p-CH=CH2) (2); the latter is copolymerised with 1,4-divinylbenzene to afford the multi-pyrazolyl containing cross-linked polymer CPPL. Reaction of CPPL with CuCl2 affords the metallated derivative CPPL-Cu, which has been shown to be an excellent catalyst for the hydrolysis of activated phosphate esters. In a different approach, 1 has been converted to the phosphinyl ligand N3P3(OC6H4-p-PPh2)5(O-C6H4-p-C6H4-p-CH=CH2), which was copolymerised with 1,4-divinylbenzene to afford the multi-phosphine containing cross-linked polymer CPPLP. Reaction of CPPLP with PdCl2(PhCN)2 affords the metallated derivative CPPLP-Pd, which has been shown to be catalytically active for the Heck arylation of olefins

Cyclotriphosphazene hydrazides as efficient multisite coordinationlLigands. &#951; <SUP>3</SUP>-fac-non-geminal-N<SUB>3</SUB>Coordination of spiro-N<SUB>3</SUB>P<SUB>3</SUB>[O<SUB>2</SUB>C<SUB>12</SUB>H<SUB>8</SUB>][N(Me)NH<SUB>2</SUB>]<SUB>4</SUB> (L) in L<SUB>2</SUB>CoCl<SUB>3</SUB> and L<SUB>2</SUB>M(NO<SUB>3</SUB>)<SUB>2</SUB> (M = Ni, Zn, Cd)

The cyclophosphazene tetrahydrazide spiro-N<SUB>3</SUB>P<SUB>3</SUB>[O<SUB>2</SUB>C<SUB>12</SUB>H<SUB>8</SUB>][N(Me)NH<SUB>2</SUB>]<SUB>4</SUB> (L) functions as a multisite coordination ligand and affords L<SUB>2</SUB>CoCl<SUB>3</SUB>&#183;2CH<SUB>3</SUB>OH (4), L<SUB>2</SUB>Ni(NO<SUB>3</SUB>)<SUB>2</SUB>&#183;2CHCl<SUB>3</SUB>&#183;2.5H<SUB>2</SUB>O (5), L<SUB>2</SUB>Zn(NO<SUB>3</SUB>)<SUB>2</SUB>&#183;2CH<SUB>3</SUB>CN&#183;2H<SUB>2</SUB>O (6), and L<SUB>2</SUB>Cd(NO<SUB>3</SUB>)<SUB>2</SUB> (7). Each of the cyclophosphazene ligands that is involved in coordination to the metal functions as a non-geminal-N<SUB>3</SUB> donor coordinating through one ring nitrogen atom and two non-geminal-NH<SUB>2</SUB> nitrogen atoms. The coordination geometry around the metal ion in 4-6 is approximately octahedral while it is severely distorted in the case of 7

Tetracoordinate Imidazole-Based Boron Complexes for the Selective Detection of Picric Acid

<i>N</i>,<i>N</i>-Dimethylamine and <i>N</i>,<i>N</i>-diphenylamine-decorated highly fluorescent imidazole borates have been synthesized and investigated as new fluorophores for the selective detection of trinitrophenol/picric acid (PA). Structural studies of a probe <b>1</b> and PA (<b>1·PA</b>) complex revealed that the adduct formed by the deprotonation of PA by the −NMe₂ group along with weak interactions is responsible for the selective detection of PA over other polynitrated organic compounds

Tetracoordinate Imidazole-Based Boron Complexes for the Selective Detection of Picric Acid

<i>N</i>,<i>N</i>-Dimethylamine and <i>N</i>,<i>N</i>-diphenylamine-decorated highly fluorescent imidazole borates have been synthesized and investigated as new fluorophores for the selective detection of trinitrophenol/picric acid (PA). Structural studies of a probe <b>1</b> and PA (<b>1·PA</b>) complex revealed that the adduct formed by the deprotonation of PA by the −NMe₂ group along with weak interactions is responsible for the selective detection of PA over other polynitrated organic compounds

Single-step synthesis of chemically cross-linked polysilastyrene and its conversion to β -silicon carbide

A new method for chemically cross-linking polysilastyrene using divinylbenzene as the cross-linking agent is reported. The procedure involves a single-step synthesis using the alkali-metal sodium to promote the polymerization of dimethyldichlorsilane in the presence of the comonomers phenylmethyldichlorosilane and divinylbenzene. The cross-linked polymer can be readily converted to &#946;-SiC on pyrolysis at 1500&#176; C. The &#946; -SiC obtained by this procedure is nanocrystalline and has a grain-size distribution of 8-20 nm

A copper-metalated, hybrid inorganic-organic polymer as an oxidative nuclease

This study describes nucleolytic activity of a copper-metalated, multisite-coordinating, hybrid polymer CPPL-Cu under oxidative conditions. Rapid relaxation of supercoiled plasmid DNA was observed and mechanistic probing by chemical and enzymatic assays revealed involvement of singlet-oxygen-derived reactive species. The heterogeneous nature of the catalyst allowed a facile recycling of the artificial nuclease

Chemically cross-linked polysilanes as stable polymer precursors for conversion to silicon carbide

Cross-linked polysilanes were prepared by the co-polymerization of Me2SiCl2 or PhMeSiCl2 with varying amounts of divinylbenzene (2-15% by weight) using molten sodium as the dehalogenating agent. All the cross-linked polysilanes were stable to air and could be processed thermally for conversion to silicon carbide. Polymers containing from 5-15% of the cross-linking agent underwent a uniform shrinkage during thermal treatment (1500 &#176; C) to afford &#946; -SiC in good yields. The ceramic was characterized by a variety of techniques including Raman and infrared spectroscopy, powder XRD, as well as Scanning Electron Microscopy (SEM)

Organostannoxanes and cyclophosphazenes as scaffolds for multi-ferrocene assemblies

The reactions of n-butylstannonic acid and di n-butyltinoxide with ferrocene monocarboxylic acid have been studied. In the former reaction a hexameric compound, [n-BuSn(O)OC(O)C<SUB>5</SUB>H<SUB>4</SUB>FeC<SUB>5</SUB>H<SUB>5</SUB>]<SUB>6</SUB> has been isolated in a quantitative yield. In the latter reaction a tetrameric compound [n-Bu<SUB>2</SUB>SnO<SUB>2</SUB>C(C<SUB>5</SUB>H<SUB>4</SUB>FeC<SUB>5</SUB>H<SUB>5</SUB><SUB>2</SUB>O]<SUB>2</SUB> has been isolated. In contrast to the drum like structure of the former compound, the latter has a ladder like arrangement. Both [n-BuSn(O)OC(O)C<SUB>5</SUB>H<SUB>4</SUB>FeC<SUB>5</SUB>H<SUB>5</SUB>]<SUB>6</SUB> and [n-Bu<SUB>2</SUB>SnO<SUB>2</SUB>C(C<SUB>5</SUB>H<SUB>4</SUB>FeC<SUB>5</SUB>H<SUB>5</SUB>)2O]<SUB>2</SUB> are electro-chemically robust and show a single oxidation peak in the cyclic voltammetric experiment corresponding to the simultaneous oxidation of six and four ferrocene substituents respectively. The hydrazine substituted cyclophosphazenes, N<SUB>3</SUB>P<SUB>3</SUB>[N(Me)NH<SUB>2</SUB>]<SUB>6</SUB>, gem-N<SUB>3</SUB>P<SUB>3</SUB>Ph<SUB>2</SUB>[N(Me)NH<SUB>2</SUB>]<SUB>4</SUB>, and gem-N<SUB>3</SUB>P<SUB>3</SUB>(O<SUB>2</SUB>C1<SUB>2</SUB>H<SUB>8</SUB>)<SUB>2</SUB>[N(Me)NH<SUB>2</SUB>]<SUB>2</SUB>, are readily condensed with ferrocene carboxaldehyde, C<SUB>5</SUB>H<SUB>5</SUB>FeC<SUB>5</SUB>H<SUB>4</SUB>CHO, to afford the corresponding cyclophosphazenes linked to the ferrocenyl moiety through the hydrazone linkage, N<SUB>3</SUB>P<SUB>3</SUB>[N(Me)N=CHC<SUB>5</SUB>H<SUB>4</SUB>FeC<SUB>5</SUB>H<SUB>5</SUB>]<SUB>6</SUB>, gem-N<SUB>3</SUB>P<SUB>3</SUB>Ph<SUB>2</SUB>[N(Me)N=CHC<SUB>5</SUB>H<SUB>4</SUB>FeC<SUB>5</SUB>H<SUB>5</SUB>]<SUB>4</SUB>, and gem-N<SUB>3</SUB>P<SUB>3</SUB>(O<SUB>2</SUB>C1<SUB>2</SUB>H<SUB>8</SUB>)<SUB>2</SUB>]N(Me)N=CHC<SUB>5</SUB>H<SUB>4</SUB>FeC<SUB>5</SUB>H<SUB>5</SUB>]<SUB>2</SUB>