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Carboxylate complexes have risen to prominence in the field of water oxidation catalysis. Here for the first time we use the higher valence of phosphinates [P(V)] relative to that of carboxylates [C(IV)] to increase ligand denticity. We describe the synthesis and characterization of a new dianionic pentadentate ligand, bcpq2− that contains a tridentate 2,2'‐bipyridine‐6‐carboxylato moiety, in addition to a 6'‐phosphinato substituent that acts as fourth ligand and bears a side arm containing a quinoline, the fifth ligand. The new bcpq ligand allows formation of [Ru(II)(bcpq)(L)] (2 a–b, L=picoline or isoquinoline) and in preliminary results, of a Co(II) complex. NMR spectroscopy, X‐ray diffraction, cyclic voltammetry, differential pulse and square wave voltammetry were used to characterize 2 a–b, with 2 b being characterized more extensively as a catalyst. Bulk electrolysis over 15 h at pH 7 was also used, showing that 2 b gave 100±5 % faradaic efficiency and remained completely homogeneous, whereas 1 b was no longer homogeneous; this comparison conclusively shows the advantage of the added denticity in the electrocatalytic context. Replacing carboxylate with P(V) phosphinate with an added arm may be used in other ligand systems to enhance the durability of homogeneous catalysts. [ABSTRACT FROM AUTHOR]

The conventional argument that extraction efficiency depends on the "basicity of the phosphoryl oxygen" is thoroughly examined in this study. The analysis involves studying the electronic structures of various ligands, such as phosphate, phosphonate, phosphinate, and phosphine oxide, as well as variations in their alkyl chain length, and their corresponding uranium complexes. The studies revealed a significant amount of destabilizing strain and steric repulsion for ligands having longer alkyl chains upon complexation. A considerable amount of stabilizing orbital and dispersion interactions compensate for these repulsions, forming stable complexes. Dispersion interactions become more significant upon chain elongation and are mainly responsible for the preference for U(VI) metal ions by ligands with lengthy alkyl chain units. The preference of phosphine oxide ligands for U(VI) is analyzed within the context of enhanced orbital interactions resulting from the energetically close donor (ligand) and acceptor (metal nitrate) orbitals. Additionally, dispersion‐based interactions also become significant, especially with larger chain lengths. The electronegative environment around the phosphorus atom, along with the existence of low‐dipole moment structures, is also examined in relation to their possible role in solvent extraction and their influence on the selectivity of ligands for uranyl species. [ABSTRACT FROM AUTHOR]

This article focuses on the synthesis of polyhydroxyurethane (PHU) materials containing novel phosphorus flame retardants (FR). Four different phosphorus compounds were grafted onto cyclic carbonate: 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), diethyl phosphite (DEP), diphenyl phosphite (DPP) and dibenzo[d,f][1,3,2]dioxaphosphepine 6-oxide (BPPO). Thus, three novel phosphorus reactive cyclic carbonates which have never been reported so far were synthetized. Phosphorus FR containing PHU materials were characterized by FTIR to evidence the total conversion of the cyclic carbonate. Moreover, the gel contents up to 80% confirmed the formation of the polymer network. Then, the thermal stability and the flame-retardant properties were investigated by thermogravimetric analyses, cone calorimeter and pyrolysis combustion flow calorimeter. The mode of action of phosphorus compounds, depending on the oxidation state, was especially highlighted. Phosphonate (+III) provided better action in a condensed phase than phosphinate thanks to a more efficient char formation. Among phosphonates, differences were observed in terms of char-formation rate and expansion. DEP provided the best flame-retardant properties, with a reduction of 76% of pHRR with 2 wt% of phosphorus in cone calorimeter analysis. Therefore, this article highlighted the different modes of action of phosphorus flame retardants, depending on the oxidation state of phosphorus, in PHU materials. [ABSTRACT FROM AUTHOR]

A fully waterborne epoxy system was prepared from waterborne sorbitol-based epoxy resin cured with an alkylated polyalkylene polyamine hardener. The flame-retardant property was accomplished by the application of different additive phosphorous flame retardants (FRs). Phosphonate polyol and ethyl ethylene glycol phosphate which are in the liquid phase, and two FRs in the form of fine-grained particles; aluminium diethyl phosphinate (AlPi), ammonium polyphosphate (APP). The flame-retardant epoxy resin blends were prepared at the same levels of phosphorus content. The results are very promising as the self-extinguishing behaviour was observed at 3%P for all the investigated FRs and at 1%P in the case of APP. Limiting oxygen index (LOI) values were practically good for all FRs and extremely improved in the case of APP. LOI was 48% for the APP sample at 3%P content. Furthermore, this blend showed the best results in the forced flaming conditions as the total heat release in cone calorimetry measurements (THR) decreased by 43% and the peak of heat release rate (pHRR) decreased by 65% with more elongated burning compared to the reference SPE matrix. The efficient solid-phase FR effect of APP was confirmed by scanning electron microscopic (SEM) and attenuated total reflection-infrared spectrometry (ATR-IR) analysis of the residual char after cone calorimetry measurements. [ABSTRACT FROM AUTHOR]

A water-soluble sorbitol polyglycidyl ether (SPE) epoxy monomer was cured with a waterborne polyamine hardener to prepare a fully waterborne epoxy system. Aluminum diethyl phosphinate (AlPi) and melamine cyanurate (MC) flame retardants (FRs) were utilized to develop the flame retardancy of this epoxy matrix. The effect of loading different weights of MC with only 1%P-content from AlPi was discussed to investigate the possible cooperative effect of these two FRs. The best results were obtained at 5% MC loading with 1%P of AlPi as the self-extinguishing behavior was observed with a good limiting oxygen index (LOI). Furthermore, under forced flaming conditions in cone calorimetry measurements, the peak of heat release rate (pHRR) decreased by 27.4%, and the total heat release (THR) decreased by 14.5% compared to the reference epoxy system. This enhancement of flame retardant properties might indicate the synergistic effect between MC and AlPi in a waterborne system. [ABSTRACT FROM AUTHOR]

Herein, we developed polyacrylonitrile (PAN)-based nanoporous composite membranes incorporating aluminum diethylphosphinate (ADEP) for use as a heat-resistant and flame-retardant separator in high-performance and safe lithium-ion batteries (LIBs). ADEP is phosphorus-rich, thermally stable, and flame retardant, and it can effectively suppress the combustibility of PAN nanofibers. Nanofibrous membranes were obtained by electrospinning, and the content of ADEP varied from 0 to 20 wt%. From the vertical burning test, it was demonstrated that the flame retardancy of the composite membranes was enhanced when more than 5 wt% of ADEP was added to PAN, potentially increasing the safety level of LIBs. Moreover, the composite membrane showed higher ionic conductivity and electrolyte uptake (0.83 mS/cm and 137%) compared to those of commercial polypropylene (PP) membranes (Celgard 2400: 0.65 mS/cm and 63%), resulting from interconnected pores and the polar chemical composition in the composite membranes. In terms of battery performance, the composite membrane showed highly stable electrochemical and heat-resistant properties, including superior discharge capacity when compared to Celgard 2400, indicating that the PAN/ADEP composite membrane has the potential to be used as a heat-resistant and flame-retardant separator for safe and high-power LIBs. [ABSTRACT FROM AUTHOR]

Summary: Flame‐retarded sorbitol‐based bioepoxy resins cured with cycloaliphatic amine hardener and containing different commercially available additive‐type flame retardants (FRs) have been prepared. Three different oxidation states of phosphorus, aluminium diethyl phosphinate (AlPi) (+1), phosphonate polyol (+3), ethyl ethylene glycol phosphate and ammonium polyphosphate (APP) (+5), have been studied. The effect of using melamine cyanurate with APP and AlPi has been assessed. The self‐extinguishing V‐0 rating according to UL‐94 flammability standard tests and very good limiting oxygen index for combustion are displayed for most flame‐retarded samples at 3 wt% phosphorus content. The flame retardancy effect for the additives was confirmed using cone calorimetry. The samples containing MC with APP at 3%P content showed a dramatic reduction of the total heat release by 60% and reduction of the peak of heat release rate by 70% compared to the reference epoxy matrix. The addition of these FRs together did not decrease the glass transition temperature significantly. [ABSTRACT FROM AUTHOR]

This article focuses on the synthesis of polyhydroxyurethane (PHU) materials containing novel phosphorus flame retardants (FR). Four different phosphorus compounds were grafted onto cyclic carbonate: 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), diethyl phosphite (DEP), diphenyl phosphite (DPP) and dibenzo[d,f][1,3,2]dioxaphosphepine 6-oxide (BPPO). Thus, three novel phosphorus reactive cyclic carbonates which have never been reported so far were synthetized. Phosphorus FR containing PHU materials were characterized by FTIR to evidence the total conversion of the cyclic carbonate. Moreover, the gel contents up to 80% confirmed the formation of the polymer network. Then, the thermal stability and the flame-retardant properties were investigated by thermogravimetric analyses, cone calorimeter and pyrolysis combustion flow calorimeter. The mode of action of phosphorus compounds, depending on the oxidation state, was especially highlighted. Phosphonate (+III) provided better action in a condensed phase than phosphinate thanks to a more efficient char formation. Among phosphonates, differences were observed in terms of char-formation rate and expansion. DEP provided the best flame-retardant properties, with a reduction of 76% of pHRR with 2 wt% of phosphorus in cone calorimeter analysis. Therefore, this article highlighted the different modes of action of phosphorus flame retardants, depending on the oxidation state of phosphorus, in PHU materials.

[Display omitted] • Poly(3-hydroxybutyrate) (PHB) polymers bearing pendent diphenylphosphinate moieties can be prepared by the simultaneous ring-opening copolymerization (ROCOP) of β-butyrolactone (BPLMe) with a phosphinate-functionalized β-lactone (BPLOP). • By tuning the ligand substituents on the yttrium catalyst, copolymers containing syndio-enriched, atactic and highly isotactic PHB segments were obtained. Copolymers constituted of one or several phosphinate moieties within the PHB macromolecular chains, with controlled molar mass and narrow dispersities, were thus synthesized. • Detailed MALDI-ToF and ESI mass spectrometric studies proved quite insightful to elucidate the nature of the various population formed and to evidence the incorporation of the phosphinate-functionalized β-lactone. • The thermal characteristics of the copolymers were investigated by DSC and TGA, revealing in comparison to those of the parent PHB homopolymers, tunable features as a function of their molar mass, tacticity and phosphinate comonomer content. Poly(3-hydroxybutyrate) (PHB) polymers functionalized with pendent diphenyl-phosphinate moieties were prepared by the simultaneous ring-opening copolymerization (ROCOP) of racemic or enantiopure β-butyrolactone (rac - or (S)-BPLMe, respectively) with racemic-(4-oxooxetan-2-yl)methyl diphenylphosphinate (rac -BPLOP). The reactions were mediated by yttrium catalysts which tunable ancillary structure enabled preparing copolymers containing syndio-enriched (P r up to 0.84; P r is the probability of racemic linkage), atactic (P r ∼ 0.50) and highly isotactic (P r < 0.06) poly(BPLMe) (P(BPLMe), aka PHB for polyhydroxybutyrate) segments, starting from rac -BPLMe or (S)-BPLMe, respectively, as assessed by detailed NMR analyses of the copolymer samples. The amount of BPLOP incorporated within the P[(BPLMe) x - co -(BPLOP) y ] samples were in line with the initial comonomer loadings (1.8–8.1 mol% vs. 2–10 mol%). The ROCOP was rather well-controlled affording linear α-isopropoxy, ω-crotonyl telechelic and cyclic random copolymers with M n,NMR up to 15,000 g.mol−1 and Ð M = 1.34–1.95. Detailed MALDI and high-resolution ESI mass spectrometric analyses evidenced the formation of three major series of macromolecules, namely the cyclic one and two linear ones end-capped with an α-isoproxy and either an ω-hydroxy or a ω-crotonate groups; for each of these series, the populations containing y = 0, 1 or 2 BPLOP repeating units were unambiguously distinguished. The thermal characteristics of the P[(BPLMe) x - co -(BPLOP) y ] copolymers were investigated by DSC and TGA, revealing in comparison to those of the parent PHB homopolymers, tunable features as a function of their molar mass, tacticity and BPLOP content. [ABSTRACT FROM AUTHOR]

This work investigates the effect of flame-retardant additives on the thermo-mechanical and dynamic properties of poly(butylene terephthalate) (PBT) vitrimers. The vitrimers were synthesized and compounded in a single step by reactive extrusion from commercially available PBT, an epoxy resin, a zinc-based transesterification catalyst, and aluminum phosphinate (AlPi) as a conventional flame retardant additive. We demonstrated that the presence of AlPi in relatively large amount (20 wt.-%) is compatible with the formation of the vitrimer network and does even play the role of a transesterification (co)catalyst accelerating the exchange reactions and improving the processability of the vitrimer. UL-94 flammability tests also confirm the effective role of AlPi as flame retardant in vitrimer. [Display omitted] • A PBT vitrimer was prepared by REX in presence of 20 wt% of aluminum diethylphosphinate. • Aluminum diethylphosphinate acts as catalyst during the synthesize. • The FR vitrimers present surprisingly short relaxation time. • The FR vitrimer has better dimensional stability and less dripping for in UL-94. [ABSTRACT FROM AUTHOR]

The reaction of Ph2P(S)ONa with B(C6F5)3 in the presence of the crown ether 15-crown-5 provided the borate complex [Na(15-crown-5)][Ph2P(S)OB(C6F5)3] (1). In one occasion a few crystals of the hydrogen-bonded complex [Na(15-crown-5)2][Ph2P(S)O···HO(S)PPh2] (2) were obtained, which formed upon the accidental hydrolysis of 1. More rationally, 2 was prepared by the reaction of Ph2P(S)OH, Ph2P(S)ONa and 15-crown-5. The molecular structures of 1 and 2 were investigated by X-ray crystallography.

It was shown that the direction of the reaction of 2-methyl-1,4-naphthoquinone with H-phosphonium salts obtained from diphenylphosphine and trifluoromethanesulfonic or trifluoroacetic acids depends on the nature of the anion. Structure of the obtained mono- and diphosphinates, as well as the quasi-phosphonium salt, was established by NMR spectroscopy and single crystal X-ray diffraction methods. [ABSTRACT FROM AUTHOR]

Organophosphonate analogues are important structural motifs that are present in bioactive natural products, pharmaceuticals, and agrochemicals. Because they are useful in a broad range of applications, much effort has focused on developing efficient synthetic methods that enable access to organophosphonates and their derivatives. However, currently available synthetic procedures rely on harsh reaction conditions and are limited to a narrow substrate scope. Our lab has recently made important advances in leveraging inert phosphonates/phosphates into functional phosphorus compounds such as mixed phosphonates, phosphates, and mixed aryl phosphate derivatives. Presented herein is an overview of recent achievements in the synthesis of phosphonate/phosphate derivatives and a summary of our recent accomplishments in Tf2 O-promoted activating strategy of phosphonate analogues. 1 Introduction 2 Direct Activating Strategy of Phosphonate Analogues 3 Late-stage Phosphonylation of Natural Compounds 4 Potential Applications 5 Summary [ABSTRACT FROM AUTHOR]

Metal-organic frameworks [M2L3]n have been synthesized using ferrocene-based ligand bearing phosphinic groups L = 1,1'-ferrocenediyl-bis(H-phosphinic acid)) and M(III) = Eu, Dy. Structures of complexes 1 and 2 are studied by IR and powder XRD analyses and shown to be isomorphic. The thermal decomposition of the synthesized compounds was studied by differential scanning calorimetry and thermogravimetry. [ABSTRACT FROM AUTHOR]

Several major challenges still remain in organophosphorus chemistry. Organophosphorus compounds are currently synthesized from phosphorus trichloride (PCl3), even though the final consumer products (such as pesticides, flame-retardants, extractants) do not contain reactive phosphorus-chlorine bonds. In order to bypass phosphorus trichloride, significant interest has been devoted to functionalizing elemental phosphorus (P4, the precursor to PCl3), red phosphorus (Pred), or phosphine (PH3). Yet, phosphinates (ROP(O)H2) are already available on an industrial scale and are the most environmentally benign, but their use as phosphorus trichloride replacements has been completely overlooked until a few years ago. An overview of some of the methodologies developed in my laboratory for P–C and P–O bond-forming reactions through phosphinate chemistry, as well as some selected applications, are presented. Another significant challenge remains the synthesis of P-stereogenic compounds. My group's recent progress in this area is also discussed. Based on menthol as an inexpensive chiral auxiliary, various menthyl phosphinates can be synthesized. These phosphinates are precursor to P-stereogenic phosphines through well-established literature transformations. [ABSTRACT FROM AUTHOR]

The reaction of (C6F5)3BOPPh2OH (prepared in situ from the rather weak Brønsted acid Ph2PO2H and the strong Lewis acid B(C6F5)3) with (t-Bu2SnO)3 provided the dinuclear complex [t-Bu2Sn(OH)OPPh2O)]2, which was investigated by X-ray crystallography.

Due to its 4 carbonic acid groups being available for bioconjugation, the cyclen tetraphosphinate chelator DOTPI, 1,4,7,10-tetraazacyclododecane-1,4,7, 10-tetrakis[methylene(2-carboxyethylphosphinic acid)], represents an ideal scaffold for synthesis of tetrameric bioconjugates for labeling with radiolanthanides, to be applied as endoradiotherapeuticals. We optimized a protocol for bio-orthogonal DOTPI conjugation via Cu(I)-catalyzed Huisgen-cycloaddition of terminal azides and alkynes (CuAAC), based on the building block DOTPI(azide)4. A detailed investigation of kinetic properties of Cu(II)-DOTPI complexes aimed at optimization of removal of DOTPI-bound copper by transchelation. Protonation and equilibrium properties of Ca(II)-, Zn(II), and Cu(II)-complexes of DOTPI and its tetra-cyclohexylamide DOTPI(Chx)4 (a model for DOTPI conjugates) as well as kinetic inertness (transchelation challenge in the presence of 20 to 40-fold excess of EDTA) were investigated by pH-potentiometry and spectrophotometry. Similar stability constants of CaII-, ZnII, and CuII-complexes of DOTPI (logK(CaL) = 8.65, logK(ZnL = 15.40, logK(CuL) = 20.30) and DOTPI(Chx)4 (logK(CaL) = 8.99, logK(ZnL) = 15.13, logK(CuL) = 20.42) were found. Transchelation of Cu(II)-complexes occurs via proton-assisted dissociation, whereafter released Cu(II) is scavenged by EDTA. The corresponding dissociation rates [kd = 25 × 10−7 and 5 × 10−7 s−1 for Cu(DOTPI) and Cu(DOTPI(Chx)4), respectively, at pH 4 and 298 K] indicate that conjugation increases the kinetic inertness by a factor of 5. However, demetallation is completed within 4.5 and 7.2 h at pH 2 and 25°C, respectively, indicating that Cu(II) removal after formation of CuAAC can be achieved in an uncomplicated manner by addition of excess H4EDTA. For proof-of-principle, tetrameric DOTPI conjugates of the prostate-specific membrane antigen (PSMA) targeting motif Lys-urea-Glu (KuE) were synthesized via CuAAC as well as dibenzo-azacyclooctine (DBCO) based, strain-promoted click chemistry (SPAAC), which were labeled with Lu-177 and subsequently evaluated in vitro and in SCID mice bearing subcutaneous LNCaP tumor (PSMA+ human prostate carcinoma) xenografts. High affinities (3.4 and 1.4 nM, respectively) and persistent tumor uptakes (approx. 3.5% 24 h after injection) confirm suitability of DOTPI-based tetramers for application in targeted radionuclide therapy.

Highlights • Phosphinate diamine (DMA) is introduced into PI backbone. • An optimum DMA ratio balances melt-flow and rigidity of PI for stronger adhesion. • Formation of polyphosphate on PI facilitates mechanical interlocking for adhesion. • Bulky phosphinate group improves dimensional stability and optical transparency. Abstract Adhesion properties of phosphinate-contained polyimide (P-PI) hybrid films were studied to develop suitable heat resistant adhesive film with excellent hot-melt processability. The diamine, 1,1-bis(4-aminophenyl)-1-(6-oxido-6H-dibenz<1, 2> oxaphosphorin-6-yl) ethane (i.e. DMA), was introduced to synthesize a series of P-PI films with different contents of DMA. The presence of the bulky phosphinate pendant group on PI backbone increased the adhesion strength and effectively reduced the melt flow after hot-pressing to flexible copper clad laminates (FCCL) without the usage of adhesive. The P-PI film tended to produce rougher surface that facilitated the mechanical interlocking effect between P-PI hybrid film and copper. The presence of characteristic phosphinate functional groups and the formation of polyphosphate layer on P-PI film were confirmed by FTIR and XPS results. The storage modulus and glass transition temperature of P-PI films were increased because of the enhanced rigidity by phosphinate groups. The presence of bulky phosphinate pendant group also reduced the coefficient of thermal expansion and dielectric constant of PI films. Although the introduction of phosphinate in PI reduced the initial weight loss temperature, the thermal stability of P-PI films was sufficient for the following manufacturing processes. Furthermore, another interesting observation was the enhancement of transparency at 400 nm for P-PI. Those properties make P-PI films useful in FCCL application. [ABSTRACT FROM AUTHOR]

Abstract: Phosphonate haben wegen ihrer einzigartigen biologischen Aktivitäten und ihres Synthesepotentials seit Jahren beachtliche Aufmerksamkeit erhalten. Modernste Methoden für die Herstellung von gemischten Phosphonaten, Phosphonamidaten, Phosphonothioaten und Phosphinaten beruhen auf harschen und wenig selektiven Reaktionsbedingungen. Hier wird eine milde Methode zur modularen Herstellung von phosphorylierten Derivaten, viele davon mit interessanten biologischen Aktivitäten, über chemoselektive Aktivierung mittels Trifluormethansulfonsäure‐Anhydrid beschrieben. Diese Vorgehensweise ermöglicht eine flexible und sogar iterative Substitution mit einem breiten Spektrum an O‐, S‐, N‐ und C‐Nukleophilen. [ABSTRACT FROM AUTHOR]

Abstract: A series of poorly soluble phenyl bis‐phosphinato bismuth(III) complexes [BiPh(OP(=O)R1R2)2] (R1=R2=Ph; R1=R2=p‐OMePh; R1=R2=m‐NO2Ph; R1=Ph, R2=H; R1=R2=Me) have been synthesised and characterised, and shown to have effective antibacterial activity against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), methicillin‐resistant Staphylococcus aureus (MRSA) and vancomycin‐resistant Enterococcus (VRE). The bismuth complexes were incorporated into microfibrillated (nano‐) cellulose generating a bismuth‐cellulose composite as paper sheets. Antibacterial evaluation indicates that the Bi‐cellulose materials have analogous or greater activity against Gram positive bacteria when compared with commercial silver based additives: silver sulfadiazine loaded at 0.43 wt % into nanocellulose produces a 10 mm zone of inhibition on the surface of agar plates containing S. aureus whereas [BiPh(OP(=O)Ph2)2] loaded at 0.34 wt % produces an 18 mm zone of inhibition. These phenyl bis‐phosphinato bismuth(III) complexes show potential to be applied in materials in healthcare facilities, to inhibit the growth of bacteria capable of causing serious disease. [ABSTRACT FROM AUTHOR]

The oxidative halogenation of diaryl- or dialkylphosphine oxides with the hypervalent iodine reagents (difluoroiodo)toluene ( p -TolIF 2 , 1 ) and (dichloroiodo)benzene (PhICl 2 , 2 ) is reported. Phosphoric fluorides could be recovered in 32–75% yield, or they could be trapped with EtOH to give the corresponding phosphinate in typically good yield. Phosphoric chlorides were not readily isolable, and were trapped with alcohol and amine nucleophiles, giving diaryl- or dialkylphos-phinates and phosphinamides in up to 90% yield. [ABSTRACT FROM AUTHOR]

The selectivity of the substitution reaction of phosphoryl chloride with organometallic reagents was investigated using NMR spectroscopy. This led to the discovery that the selectivity of the substitution reaction can be tuned by choosing a proper organometallic reagent. A phosphinate could be obtained by using a Grignard reagent whereas an organozinc reagent provided a phosphonate. Based on these results, one-pot synthetic methods for the preparation of phosphinates and phosphonates using commercially available starting materials were developed. Both methods allow the synthesis of a broad range of either phosphinate or phosphonate derivatives in a straightforward and general procedure. Moreover, using these one-pot procedures, mixed systems substituted with different alkyl/aryl groups can be prepared. [ABSTRACT FROM AUTHOR]

A novel bridged 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivative (PN-DOPO) was used to fabricate a flame-retardant glass fiber-reinforced polyamide 6T (GFPA6T). The effects of PN-DOPO on the flame retardancy, thermal decomposition, and pyrolysis behavior of GFPA6T was systematically investigated, compared to neat GFPA6T and its composite flames retarded by aluminium diethylphosphinate (OP1230). The flame retardancy, thermal stabilities, and burning behaviors of the composites were evaluated by vertical burning test (UL-94), limiting oxygen index (LOI), thermogravimetric analysis (TGA), and cone calorimeter test. Moreover, the flame-retardant mechanism was analyzed by pyrolysis-gas chromatograph/mass spectrometer (Py-GC/MS), Fourier transform infrared coupled with the thermogravimetric analyzer (TG-FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Results reveal that the modified GFPA6T, with the addition of 15 wt% PN-DOPO, achieves a V-0 rating and LOI value of 28.9%, whereas introducing OP1230 at levels up to 17.5 wt% can achieve a V-0 rating and LOI value of 40.1%. The superior flame retardancy for GFPA6T/PN-DOPO system can be attributed to two factors as follows: the release of pyrolytic gases containing phosphorus-based aromatic structures and nonflammable gases at the early stage, thereby playing an important role in the gas phase, and the formation of char layer consisting of phosphorus-containing char layer and polyaromatic structures in the condensed phase. In comparison, diethyl-phosphorus oxides and their derivatives are detected in the gas phase for GFPA6T/OP1230 samples, and the residues consist of aluminum phosphorus oxides, polyphosphates, and a slight amount of charred polymer. [ABSTRACT FROM AUTHOR]

Phosphorous-containing molecules are essential constituents of all living cells. While the phosphate functional group is very common in small molecule natural products, nucleic acids, and as chemical modification in protein and peptides, phosphorous can form P–N (phosphoramidate), P–S (phosphorothioate), and P–C (e.g., phosphonate and phosphinate) linkages. While rare, these moieties play critical roles in many processes and in all forms of life. In this review we thoroughly categorize P–N, P–S, and P–C natural organophosphorus compounds. Information on biological source, biological activity, and biosynthesis is included, if known. This review also summarizes the role of phosphorylation on unusual amino acids in proteins (N- and S-phosphorylation) and reviews the natural phosphorothioate (P–S) and phosphoramidate (P–N) modifications of DNA and nucleotides with an emphasis on their role in the metabolism of the cell. We challenge the commonly held notion that nonphosphate organophosphorus functional groups are an oddity of biochemistry, with no central role in the metabolism of the cell. We postulate that the extent of utilization of some phosphorus groups by life, especially those containing P–N bonds, is likely severely underestimated and has been largely overlooked, mainly due to the technological limitations in their detection and analysis.

Carbon-phosphorus (C−P) bond-forming reactions via homolytic aromatic substitution (HAS) of non-functionalized substrates with phosphinylidene P(O)H compounds is becoming a useful synthetic tool for the preparation of aryl and heteroaryl phosphonates, phosphinates, and phosphine oxides. This review specifically covers recent work using manganese-mediated free radical processes. Several research groups employ expensive Mn(OAc)3, whereas our own contributions focus on the novel and inexpensive Mn(OAc)2/MnO2 system. [ABSTRACT FROM AUTHOR]

In this article, we explore, both theoretically and experimentally, the general reactivity of alkyl hydrogeno-phenylphosphinates with alcohols. We show that alcohol molecules act exclusively as nucleophilic species, and add to alkyl hydrogeno-phenylphosphinates, leading to pentacoordinated intermediates. These intermediates are shown to subsequently competitively undergo alcohol eliminations and/or Berry pseudorotations. This offers several possible routes for racemizations and/or alcohol exchange reactions. Transition standard Gibbs free energies predicted from DFT calculations for the overall alcohol exchange mechanism are shown to be compatible with those experimentally measured in case ethanol reacts with ethyl hydrogeno-phenylphosphinate (134.5∼136.0 kJ mol at 78 °C). [ABSTRACT FROM AUTHOR]

Two flame retardants, aluminium poly-hexamethylenephosphinate ( APHP) and bisphenol-A bis(diphenyl phosphate) ( BDP), were incorporated into diglycidyl ether of bisphenol A ( DGEBA) thermoset with 4,4′-diaminodiphenyl sulfone ( DDS) as curing agent, and then the synergistic flame-retardant behaviors of the cured thermosets were investigated. Compared with thermosets containing 10 wt% APHP and 10 wt% BDP alone, the sample with 3.3 wt% APHP and 6.7 wt% BDP (3.3% APHP/6.7% BDP/ EP; EP is DGEBA/ DDS) possessed a better flame-retardant effect since its limited oxygen index reached 35.0% and in the UL94 test it passed the V-0 rating. The cone calorimeter test revealed that the 3.3% APHP/6.7% BDP/ EP sample generated less gaseous fragments and more smoke particles instead of fuels and verified that APHP and BDP exhibited an outstanding synergistic effect on the barrier effect. Macroscopic digital photos and micrographs from scanning electron microscopy further disclose that BDP facilitated the formation of a flexible film covering holes in the residue. The flexible film was combined with aluminium phosphate particles which were produced by decomposed APHP, thereby forming a char layer with increased barrier effect. The synergistic barrier effect from APHP and BDP imposed a better flame-retardant performance for epoxy thermosets. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

The reaction of Ph2P(S)ONa with B(C6F5)3 in the presence of the crown ether 15-crown-5 provided the borate complex [Na(15-crown-5)][Ph2P(S)OB(C6F5)3] (1). In one occasion a few crystals of the hydrogen-bonded complex [Na(15-crown-5)2][Ph2P(S)O...HO(S)PPh2] (2) were obtained, which formed upon the accidental hydrolysis of 1. More rationally, 2 was prepared by the reaction of Ph2P(S) OH, Ph2P(S)ONa and 15-crown-5. The molecular structures of 1 and 2 were investigated by X-ray crystallography. [ABSTRACT FROM AUTHOR]

The reaction of Ph2P(S)ONa with B(C6F5)3 in the presence of the crown ether 15-crown-5 provided the borate complex [Na(15-crown-5)][Ph2P(S)OB(C6F5)3] (1). In one occasion a few crystals of the hydrogen-bonded complex [Na(15-crown-5)2][Ph2P(S)O...HO(S)PPh2] (2) were obtained, which formed upon the accidental hydrolysis of 1. More rationally, 2 was prepared by the reaction of Ph2P(S) OH, Ph2P(S)ONa and 15-crown-5. The molecular structures of 1 and 2 were investigated by X-ray crystallography. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks [M2L3]n have been synthesized using ferrocene-based ligand bearing phosphinic groups L = 1,1′-ferrocenediyl-bis(H-phosphinic acid)) and M(III) = Eu, Dy, Y. Structures of complexes 1–3 are studied by TG, IR and powder XRD analyses and shown to be isomorphic. The redox properties of the CPs 1–3 were studied. [ABSTRACT FROM AUTHOR]

Porous aerogel has been synthesized using ferrocene-based ligand bearing phosphinic groups (H2fcdHp = 1,1′-ferrocenediyl-bis(H-phosphinic acid)). Fe-fcdHp was obtained in a sol–gel approach followed by supercritical CO2 drying. The N2 adsorption properties of the aerogel were investigated. [ABSTRACT FROM AUTHOR]