PCl3- and organometallic-free synthesis of tris(2-picolyl)phosphine oxide from elemental phosphorus and 2-(chloromethyl)pyridine hydrochloride

In the superbase KOH/H₂O/toluene/phase-transfer catalyst system, 2-picolyl chloride, generated in situ from 2-(chloromethyl)pyridine hydrochloride, reacts with elemental phosphorus at 65–95?°C for 3?h to afford tris(2-picolyl)phosphine oxide in 50% yield. Single crystal X-ray analysis of the latter revealed one polymorph form of this tertiary phosphine oxide.     

Molecular structure of (3,5-diallylisocyanuratomethyl)bis(chloromethyl)phosphine oxide. Synthesis of (3,5-diallylisocyanuratomethyl)phosphine sulfides

X-Ray study of the (3,5-diallylisocyanuratomethyl)bis(chloromethyl)phosphine oxide showed that the phosphorylmethyl group is bonded to the nitrogen atom of the cycle. Reaction of the tris(chloromethyl)phosphine sulfide with sodium diallylisocyanurate gave (3,5-diallylisocyanuratomethyl)bis(chloromethyl)phosphine sulfide, and treatment of the tris(3,5-diallylisocyanuratomethyl)phosphine oxide with phosphorus pentasulfide gave a tris(3,5-diallylisocyanuratomethyl)bis(chloromethyl)phosphine sulfide.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1446–1448, August, 1993.     

Two Cd(II) coordination polymers based on tris(p-carboxylphenyl)phosphine oxide accompanied by in situ ligand formation

Two Cd(II) coordination polymers constructed from tris(p-carboxylphenyl)phosphine oxide (H₃TPO), [Cd(HTPO)(1,4-bix)·3H₂O]_n (1) and [Cd₂(HTPO)(HBPO)(H₂O)₂]_n (2) (1,4-bix = 1,4-bis(imidazol-1-ylmethyl)benzene, H₃BPO = bis(4-carboxylphenyl)phosphinic acid), were synthesized and identified by IR, elemental analysis, and single-crystal X-ray diffraction analysis. The 1,4-bix ligand leads to 1 as a ladder-like 1D chain structure. In 2, adjacent Cd₂ units are bridged by HBPO^2– and HTPO^2– ligands to form a 3D structure. The H₃BPO ligand is formed from the in situ reaction of H₃TPO. It is the first example from hydrated Cd(II) salt promoting partial hydrolysis of a phosphine oxide ligand. The thermal behavior and solid-state photoluminescence properties correlated with the corresponding structural features were investigated.     

Effect of Mo content in MoO3/g-Al2O3 on the catalytic activity for transesterification of dimethyl oxalate with phenol

The influence of molybdenum content on the catalytic performance in the transesterification of dimethyl oxalate (DMO) with phenol to methyl phenyl oxalate (MPO) and diphenyl oxalate (DPO) was investigated. The results indicated that the MoO₃/Al₂O₃ catalyst with 14 wt% Mo content gave maximal DPO yield with 6.1% and 75.1% DMO conversion. The component, structure and phase of MoO₃/Al₂O₃ catalysts were characterized by means of X-ray diffraction (XRD), BET specific surface area, temperature-programmed desorption of ammonia (NH₃-TPD), and FTIR analysis of adsorbed pyridine. This revised version was published online in June 2006 with corrections to the Cover Date.     

Tris(2‐pyridyl)­phosphine oxide: how C—H⃛O and C—H⃛N interactions can affect crystal packing efficiency

Tris(2‐pyridyl)­phosphine oxide, (I), C₁₅H₁₂N₃OP, is isomorphous with tris(2‐pyridyl)­phosphine. Because of a combination of C—H⋯O and C—H⋯N interactions, the crystal packing is denser in the title compound than in the related compounds tri­phenyl­phosphine oxide and tris(2‐pyridyl)­phosphine.     

Combinations of titanium(IV) oxide,iron(III) oxide and molybdenum(VI) oxide as flame retardants and smoke suppressants for thermoplastic polymers

An inert metal oxide (TiO₂), a catalytic oxide (Fe₂O₃) and an oxide which forms volatile halides (MoO₃) have been incorporated into polypropylene and polystyrene on their own, in combination with one another, and in the absence and presence of a halogen compound (Cereclor 70 or decabromobiphenyl oxide). Studies of the resulting flame-retardant and smoke-suppressant effects of the additive systems have been carried out by means of triangular diagrams. None of the systems investigated has any sizeable effect on the flammability of polypropylene, the limiting oxygen indices being raised by no more than 8 units. A positive interaction between Cereclor 70 and molybdenum oxide results however both in an improvement in the degree of flame retardance of this polymer and in a decrease in its already rather low smoke-producing tendency. These additive systems have proved more effective in the case of polystyrene. The decreased flammability manifests itself as an increase of up to 12 LOI units, while the maximum smoke density resulting from the combustion of the polymer is considerably decreased. In some cases the maximum smoke density, D_s, is less than 5% of the value for the pure polymer. The most efficient flame-retardant and smoke-suppressant systems generally involve molybdenum oxide and these are, in particular, ternary systems containing also another metal oxide and decabromobiphenyl oxide. Iron(III) oxide has little effect on its own but nevertheless considerably enhances the activity of the other metal oxides.     

Binary mixtures of metal compounds as flame retardants for organic polymers

Studies have been made of the effect on the flammability of thermoplastic polymers of the partial or total replacement of one metal compound by another in the presence also of a suitable halogen compound; particular attention has been paid to systems where the primary flame retardant is antimony(III) oxide. With each binary metal compound system investigated, ten different compositions have been chosen so as to provide a symmetrical arrangement of points within a triangular design; resulting calculated values of the limiting oxygen index for each polymer-flame retardant system for a given polymer are shown as a graphical contour analysis. Comprehensive studies of several systems show that both iron(III) oxide and aluminium oxide monohydrate can significantly enhance the flame-retardant action of antimony(III) oxide but that several other metal compounds, although not as effective as Sb₂O₃, may nevertheless be used as adequate partial replacements for it. The Fe₂O₃-SnO₂-H₂O system can also act as an effective flame retardant under certain conditions. The SnOZnO system perhaps best illustrates the importance of the polymer substrate and of the total additive loading as factors controlling the flame-retardant effectiveness. For all the systems studied, however, ABS is a much better substrate than HDPE. The results of a reasonably detailed study of the flame retardance conferred by several different compositions of a binary metal compound mixture give a much more reliable indication of the effects on polymer flammability of the constituent metal compounds than are obtained simply by replacement of a given concentration of one compound by another.     

s-Triazine containing flame retardant hyperbranched polyamines: Synthesis, characterization and properties evaluation

A s-triazine containing hyperbranched polyamine (HBPA) has been synthesized from cyanuric chloride and aromatic diamine, 4,4′-(1,4-phenylenediisopropylidene) bis-aniline by nucleophilic displacement polymerization technique using an A₂ + B₃ approach with high yield (>80%). The synthesized polymer has been characterized by ¹H NMR, ¹³C NMR, FT-IR spectroscopic studies, elemental analysis, solubility and measurement of solution viscosity. The thermogravimetric (TG) analysis and differential scanning calorimetric (DSC) studies indicate that the polymer is thermostable upto 290 °C without any decomposition and has glass transition temperature of 243 °C. The flame retardancy of the pure powder polymer and the blends with linear commercial polymers such as plasticized PVC and LDPE with this hyperbranched polymer were investigated by the measurement of limiting oxygen index (LOI) value. The results show that the polymer has self-extinguishing characteristic (LOI = 38) and acts as an effective flame retardant additive for the above linear base polymers. The synergistic effect of this hyperbranched flame retardant was observed with triphenyl phosphine oxide in the same base polymers. The flammability efficiency of the hyperbranched polyamine is also evaluated by help of thermogravimetric (TG) analysis. The heat aging and leaching in different chemical media did not influence the flame retardancy of the blends.     

Trisyl modification of epoxy- and chloromethyl-polysiloxanes

The new bulky organosilicon compound HC(Me₂SiCH₂CH₂CH₂OCH₂CycloCHCH₂O)₃ was synthesized by hydrosilylation of tris(dimethylsilyl)methane (HMe₂Si)₃CH and allyl glycidyl ether (AGE) in the presence of H₂PtCl₆ as a catalyst. Polysiloxanes containing 3-(2,3-epoxypropoxy)propyl and chloromethylphenethyl groups were synthesized by hydrosilylation of AGE and chloromethyl styrene (CMS) with hydrogen-containing polymethylsiloxane (PMHS). Both types of polymers could be modified by incorporation of the highly sterically-demanding tris(trimethylsilyl)methyl [trisyl = (Me₃Si)₃C] substituent. The trisyl (Tsi) groups were attached to the obtained polymers as side chains by reacting excess trisyl lithium with benzyl chloride and epoxy groups. The epoxy groups possess a higher reactivity for TsiLi than the chloromethyl groups. The ring opening reaction between the epoxy groups and TsiLi is fast. The modification increases the rigidity of the polymers as shown by differential scanning calorimetry analysis. The incorporation of the Tsi groups into the polymer structure creates macromolecules of novel architecture with potential use as membranes for fluid separation. All the resulting polymers were characterized by FT-IR and ¹H NMR spectroscopy.     

Magnetic and Thermal Properties of Novel Poly(ether-amide)/Fe3O4 Nanocomposite Containing Phosphine Oxide Group

New poly(ether-amide) nanocomposite containing phosphine oxide was prepared via solution polymerization process from synthesized poly(ether-amide) and Fe₃O₄ nanoparticles in a solution of N,N-dimethylformamide. Uniform monodisperse Fe₃O₄ nanoparticles were synthesized at room temperature via a facile sonochemical reaction. Poly(ether-amide) (PEA) as the polymer matrix was synthesized from reaction of 1,4-(4-carboxy phenoxy)butane (1) and bis(3-amino phenyl)phenyl phosphine oxide (2) via a direct polycondensation reaction. Nanoparticle and nanocomposite were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared. The effect of the presence of Fe₃O₄ nanoparticles on the thermal properties of PEA was studied using thermogravimetric analysis in nitrogen atmospheres. The magnetic properties of the sample were also investigated using an alternating gradient force magnetometer. We found that the Fe₃O₄ nanoparticles exhibit a ferromagnetic behaviour with a saturation magnetization of 59 emu/g and a coercivity of 104 Oe at room temperature. The coercivity of PEA/Fe₃O₄ nanocomposites is found to be 126 Oe, higher than 104 Oe which is obtained for Fe₃O₄.     

Metal‐Ion Sensing Europium(III) Complexes with Bidentate Phosphine Oxide Ligands Containing a 2,2′‐Bipyridine Framework

Novel Eu^III complexes with bidentate phosphine oxide ligands containing a bipyridine framework, i.e., [3,3′‐bis(diphenylphosphoryl)‐2,2′‐bipyridine]tris(hexafluoroacetylacetonato)europium(III) ([Eu(hfa)₃(BIPYPO)]) and [3,3′‐bis(diphenylphosphoryl)‐6,6′‐dimethyl‐2,2′‐bipyridine]tris(hexafluoroacetylacetonato)europium(III) ([Eu(hfa)₃(Me‐BIPYPO)]), were synthesized for lanthanide‐based sensor materials having high emission quantum yields and effective chemosensing properties. The emission quantum yields of [Eu(hfa)₃(BIPYPO)] and [Eu(hfa)₃(Me‐BIPYPO)] were 71 and 73%, respectively. Metal‐ion sensing properties of the Eu^III complexes were also studied by measuring the emission spectra of Eu^III complexes in the presence of Zn^II or Cu^II ions. The metal‐ion sensing and the photophysical properties of luminescent Eu^III complexes with a bidentate phosphine oxide containing 2,2′‐bipyridine framework are demonstrated for the first time.     

Crystal structure of tris(chloromethyl)phosphine oxide

In the crystalline phase, tris(chloromethyl)phosphine oxide is a tgg conformer (with a transoid Cl-C-P-C-Cl chain).Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 7, pp. 1554–1556, July, 1990.     

Long-Range LMCT Coupling in EuIII Coordination Polymers for an Effective Molecular Luminescent Thermometer**

A design for an effective molecular luminescent thermometer based on long-range electronic coupling in lanthanide coordination polymers is proposed. The coordination polymers are composed of lanthanide ions Eu^III and Gd^III, three anionic ligands (hexafluoroacetylacetonate), and a chrysene-based phosphine oxide bridges (6,12-bis(diphenylphosphoryl)chrysene). The zig-zag orientation of the single polymer chains induces the formation of packed coordination structures containing multiple sites for CH-F intermolecular interactions, resulting in thermal stability above 350 °C. The electronic coupling is controlled by changing the concentration of the Gd^III ion in the Eu^III-Gd^III polymer. The emission quantum yield and the maximum relative temperature sensitivity (S_m) of emission lifetimes for the Eu^III-Gd^III polymer (Eu:Gd=1:1, Φ_tot=52 %, S_m=3.73 % K⁻¹) were higher than those for the pure Eu^III coordination polymer (Φ_tot=36 %, S_m=2.70 % K⁻¹), respectively. Enhanced temperature sensing properties are caused by control of long-range electronic coupling based on phosphine oxide with chrysene framework.     

Synthesis of polymers containing tertiary phosphine oxides using complex bases

Tertiary phosphine oxides have been prepared in excellent yield from primary alkyl halides or aromatic halides and activated sodium phosphinates obtained by reaction of dialkyl phosphine oxides with complex bases (NaNH₂/tBuONa). This reaction has been successfully applied to soluble and cross-linked bromopolystyrenes and to macroporous polystyrenes with bromooctyl substituents giving polymers which contain pendant phosphine oxide groups.     

Reaction of tris(hydroxymethyl)phosphine and cinnamaldehyde in methanol

Reaction of tris(hydroxymethyl)phosphine with excess cinnamaldehyde in CH₃OH or CD₃OD, followed using NMR, proceeds via several phosphorus-containing intermediates, multiple transformations of organic parts, and with the solvent H/D isotope effect on products. In both solvents, one CH₂OH group of tris(hydroxymethyl)phosphine is readily replaced by the cinnamaldehyde moiety to give the primary product, a 1,3-oxaphosphorinane derivative. Slower replacement of the second CH₂OH group leads to a mixture of aliphatic and heterocyclic phosphine intermediates in a ratio of ~4:1 in CH₃OH and ~1:1 in CD₃OD; both intermediates contain alcohol and aldehyde groups and convert rapidly into intra- and intermolecular hemiacetals. The hemiacetals of the aliphatic phosphine rearrange further into an unsymmetrical trialkylphosphine oxide, whereas the hemiacetals of the heterocyclic phosphine react with the third mole of cinnamaldehyde to replace the third CH₂OH group of tris(hydroxymethyl)phosphine. All intermediates and products are formed as mixtures of stereoisomers.     

Boronate Covalent and Hybrid Organic Frameworks Featuring PIII and P=O Lewis Base Sites

Two covalent organic frameworks comprising Lewis basic P^III centers and Lewis acidic boron atoms were prepared by poly-condensation reactions of newly obtained tris(4-diisopropoxyborylphenyl)phosphine with 2,3,6,7,10,11-hexahydroxytriphenylene and 2,3,6,7-tetrahydroxy-9,10-dimethylanthracene. Obtained materials exhibit significant sorption of dihydrogen (100 cm³ g⁻¹ at 1 bar at 77 K), methane (20 cm³ g⁻¹ at 1 bar at 273 K) and carbon dioxide (50 cm³ g⁻¹ at 1 bar at 273 K). They were exploited as solid-state ligands for coordination of Pd⁰ centers. Alternatively, in a bottom-up approach, boronated phosphine was treated with Pd₂dba₃ and poly-condensated, yielding hybrid materials where the polymer networks are formed by means of covalent boronate linkages and coordination P−Pd bonds. In addition, the analogous materials based on phosphine oxide were synthesized. The DFT calculations on framework–guest interactions revealed that the behavior of adjacent boron and phosphorus/phosphine oxide centers is reminiscent of that found in Frustrated Lewis Pairs and may improve sorption of selected molecules.     

Fluoride‐terminated hyperbranched poly(arylene ether phosphine oxide)s via nucleophilic aromatic substitution

A series of AB_x‐type triarylphosphine oxide monomers, bis‐(4‐fluorophenyl)‐(4‐hydroxyphenyl)phosphine oxide ( 4a ), bis‐(3,4‐difluorophenyl)‐(4‐hydroxyphenyl)phosphine oxide ( 4b ), and 4‐hydroxyphenyl‐bis‐(3,4,5‐trifluorophenyl)phosphine oxide ( 4c ) were prepared, characterized, and polymerized under nucleophilic aromatic substitution conditions [N‐methylpyrrolidone (NMP), K₂CO₃] to provide the corresponding hyperbranched poly(arylene ether phosphine oxide)s with number‐average molecular weights ranging from 9200 to 14,600 Da. NMR spectroscopic analysis indicated the presence of highly branched products with an approximate degree of branching of 0.57. The polymers were soluble in a variety of typical organic solvents and displayed excellent thermal stability. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 1456–1467, 2002     

Koordinationspolymere mit Tris(4‐carboxyphenyl)‐phosphanoxid als Ligand – Synthese,Kristallstrukturen und topologische Untersuchungen

The solvothermal reaction of MnCl₂ · 4H₂O or CoCl₂ · 6H₂O with tris(4‐carboxyphenyl)‐phosphine oxide (H₃TPO), in DMF orDMA resulted in the four coordination polymers [M₃(tpo)₂(dmf)(H₂O)₂]( 1 : M = Mn; 2 : M = Co), (NMe₂H₂)[Mn₃Cl(HCO₂)(htpo)(tpo)(H₂O)] ( 3 ) and (NMe₂H₂)[Mn₃(tpo)₂(OAc)] ( 4 ). Structural characterization by X‐ray crystallography revealed that 1 – 4 form 3‐periodical infinite networks; after synthesis solvent molecules occupy the framework pores. The topologies of the networks in 1 , 2 and 3 are unprecedented in literature and are systematically characterized. Furthermore, these topologies could be derived from hexagonal close packing ( 1 , 2 ) and cubic close packing ( 3 ), respectively.Compounds 1 , 2 and 4 were synthesized as pure crystalline materials, their thermal behaviour was examined by TG/DTA measurements and temperature dependent PXRD. 1 , 2 and 4 show remarkable thermal stability with decomposition temperatures between 450 and 500 °C. Temperature dependent PXRD measurements of compounds 1 and 2 reveal a structural transition at 260 °C, framework 4 loses its crystallinity at 210 °C.     

Synergic extraction of uranium(VI) by combination of tri-iso-octylamine and neutral donors

Synergistic effect of neutral donors like tri-butyl phosphate (TBP), triphenyl phosphine oxide (TPPO), trioctyl phosphine oxide (TOPO), and dimethyl sulphoxide (DMSO) on the extraction of uranium(VI) by tri-isooctyl amine into CCl₄ is reported. Synergistic coefficients and adduct formation constants are calculated from distribution data and correlated with relative donor abilities of added bases.     

Multifunctional Lanthanide‐Based Metal–Organic Frameworks with a Polyheterotopic Ligand: Doped with Ytterbium(III) for Luminescence Enhancement and Selective Dye Adsorption

The chemistry of metal–organic frameworks has been progressing fast with its exciting potential in multifunctional applications. A series of three‐dimensional lanthanide‐based metal–organic frameworks, {[Ln(HTPO)(NO₃)(H₂O)]⋅x(CH₃CN)⋅y(H₂O)}_n (Ln=Eu ( 1 ), Tb ( 2 ), Gd ( 3 ), Sm ( 4 ), Dy ( 5 ), Nd ( 6 )), {[Eu(TPO)(HCOO)_0.5]⋅(H₃O)_0.5}_n ( 7 ), {[Eu(TPO)(DMF)]⋅(solv)_x}_n ( 8 ; DMF= N,N‐dimethylformamide), and {[Eu(TPO)(DMA)]⋅(solv)_x}_n ( 9 ; DMA=dimethylacetamide) were synthesized with semirigid C₃‐symmetric ligand tris(4‐carboxylphenyl)phosphine oxide (H₃TPO). In these frameworks, the H₃TPO ligand exists in a totally different configuration. Framework 1 exhibits good breathing properties for absorbing more guest molecules through a solvent‐induced single‐crystal‐to‐single‐crystal (SC–SC) transformation involving a configuration transformation of the organic linker in the framework. The ytterbium ion was doped into 1 to improve the luminescent performance (lifetime and quantum yield) of the red europium emission. Among a series of Eu_1−xYb_xTPO samples, Eu_0.88Yb_0.12TPO showed enhanced luminescence intensity (≈5.1 times that of the pure europium system), and the lifetime increased from 1073.08 to 1236.57 μs. Moreover, the porosity of these frameworks allows them to efficiently adsorb dye molecules with high selectivity and efficiency.