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This paper presents the efficient reduction of phosphinoylacetic acid esters and 3-phosphorylated coumarin to their corresponding phosphino-boranes using BH₃-THF complexes. Optimized conditions for the reduction of phosphinoylacetic acid esters resulted in high yields of phosphinoborates. The straightforwardness and efficiency of the process were demonstrated for diarylphosphinoylacetic acid ethyl esters, as well as P-stereogenic L-menthyl esters, where the simultaneous reduction of the strong P=O bond and the ester group was exclusively observed for the first time. The study also highlighted the significant influence of steric effects with bulky substituents, such as the menthol group or the 1-naphthyl substituent at phosphorus, on the reduction efficiency. However, the reduction of 3-phosphorylated coumarins produced an unexpected reaction product: a 2,3-dihydrobenzofuran derivative. The present findings provide valuable information on the direct reduction of phosphine oxides and related compounds, demonstrating the versatility of borane complexes in synthetic chemistry, and provide new perspectives for studying the problems of symmetry and asymmetry in the chemistry of such transformations. [ABSTRACT FROM AUTHOR]

The surface morphology of perovskite films significantly influences the performance of perovskite light-emitting diodes (PeLEDs). However, the thin perovskite thickness (~10 nm) results in low surface coverage on the substrate, limiting the improvement of photoelectric performance. Here, we propose a molecular additive strategy that employs pentafluorophenyl diphenylphosphinate (FDPP) molecules as additives. P=O and Pentafluorophenyl (5F) on FDPP can coordinate with Pb2+ to slow the crystallization process of perovskite and enhance surface coverage. Moreover, FDPP reduces the defect density of perovskite and enhances the crystalline quality. The maximum brightness, power efficiency (PE), and external quantum efficiency (EQE) of the optimal device reached 24,230 cd m−2, 82.73 lm W−1, and 21.06%, respectively. The device maintains an EQE of 19.79% at 1000 cd m−2 and the stability is further enhanced. This study further extends the applicability of P=O-based additives. [ABSTRACT FROM AUTHOR]

Thiochalcones undergo cycloaddition reactions in THF solution at 60 °C with the synthetically unexplored 1-phenyl-4H-phosphinin-4-one 1-oxide in a highly regio- and stereoselective manner, yielding hitherto unknown bicyclic P,S-heterocycles containing fused thiopyran and phosphinine rings. The stereochemical structures of two of the obtained (4+2)-cycloadducts were unambiguously assigned by means of the X-ray single-crystal analysis. Based on these assignments, a concerted mechanism of the hetero-Diels–Alder reaction via the preferred endo approach of the heterodiene from the less hindered P=O side of the phosphininone molecule is postulated to explain the established rac-(4RS,8SR,9SR,10SR)-configured (4+2)-cycloadducts isolated as major products. [ABSTRACT FROM AUTHOR]

2,6-Diaryl-4H-tetrahydro-thiopyran-4-ones and corresponding sulfoxide and sulfone derivatives were designed to lower the major toxicity of their parent anti-kinetoplatidal diarylideneacetones through a prodrug effect. Novel diastereoselective methodologies were developed and generalized from diarylideneacetones and 2,6-diaryl-4H-tetrahydro-thiopyran-4-ones to allow the introduction of a wide substitution profile and to prepare the related S-oxides. The in vitro biological activity and selectivity of diarylideneacetones, 2,6-diaryl-4H-tetrahydro-thiopyran-4-ones, and their S-sulfoxide and sulfone metabolites were evaluated against Trypanosoma brucei brucei, Trypanosoma cruzi, and various Leishmania species in comparison with their cytotoxicity against human fibroblasts hMRC-5. The data revealed that the sulfides, sulfoxides, and sulfones, in which the Michael acceptor sites are temporarily masked, are less toxic against mammal cells while the anti-trypanosomal potency was maintained against T. b. brucei, T. cruzi, L. infantum, and L. donovani, thus confirming the validity of the prodrug strategy. The mechanism of action is proposed to be due to the involvement of diarylideneacetones in cascades of redox reactions involving the trypanothione system. After Michael addition of the dithiol to the double bonds, resulting in an elongated polymer, the latter—upon S-oxidation, followed by syn-eliminations—fragments, under continuous release of reactive oxygen species and sulfenic/sulfonic species, causing the death of the trypanosomal parasites in the micromolar or submicromolar range with high selectivity indexes. [ABSTRACT FROM AUTHOR]

A series of optically pure aziridine phosphines and their corresponding phosphine oxides were synthesized through established chemical methodologies. The compounds were systematically investigated for their biological properties. Notably, all synthesized compounds demonstrated moderate antibacterial activity only against the reference strain of Staphylococcus aureus. However, compounds 5 and 7 exhibited noteworthy cell viability inhibition of human cervical epithelioid carcinoma HeLa cells and endometrial adenocarcinoma Ishikawa cells. Further studies of these compounds revealed additional biological effects, including disruption of the cell membrane in high concentrations, cell cycle arrest in the S phase, and the induction of reactive oxygen species (ROS). Comparative analysis of the two classes of chiral organophosphorus derivatives of aziridines indicated that chiral phosphine oxides displayed significantly higher biological activity. Consequently, these findings suggest that chiral phosphine oxides may be potential candidates for the development of anticancer drugs. In light of the significant interest in preparations whose structure is based on a three-membered aziridine ring in terms of potential anticancer therapy, this research fits into the current research trend and should constitute a valuable addition to the current state of knowledge and the existing library of aziridine derivatives with anticancer properties. [ABSTRACT FROM AUTHOR]

The design and manufacturing of objects in various industries have been fundamentally altered by the introduction of D-dimensional (3D) and four-dimensional (4D) printing technologies. Four-dimensional printing, a relatively new technique, has emerged as a result of the ongoing development and advancements in 3D printing. In this study, a stimulus-responsive material, N-Vinylcaprolactam-co-DEGDA (NVCL-co-DEGDA) resin, was synthesised by Stereolithography (SLA) 3D printing technique. The N-Vinylcaprolactam-co-DEGDA resins were initiated by the Diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) photoinitiator. A range of Di(ethylene glycol) diacrylate (DEGDA) concentrations in the NVCL-co-DEGDA resin was explored, ranging from 5 wt% to 40 wt%. The structural properties of the 3D printed objects were investigated by conducting Attenuated Total Reflectance–Fourier Transform Infrared Spectroscopy (ATR-FTIR). Additionally, the 3D printed samples underwent further characterisation through differential scanning calorimetry (DSC) and swelling analysis. The results revealed an inverse relationship between DEGDA concentration and Tg values, indicating that higher concentrations of DEGDA resulted in lower Tg values. Additionally, the pulsatile swelling studies demonstrated that increasing DEGDA concentration prolonged the time required to reach the maximum swelling ratio. These findings highlight the influence of DEGDA concentration on both the thermal properties and swelling behaviour of 3D printed samples. [ABSTRACT FROM AUTHOR]

The research work of M. Kadirov's group investigates the use of sodium pectate-nickel complexes as catalysts in fuel cells for hydrogen oxidation and oxygen reduction [[25]]. 36293359 25 Nizameev I.R., Kadirov D.M., Nizameeva G.R., Sabirova A.F., Kholin K.V., Morozov M.V., Mironova L.G., Zairov R.R., Minzanova S.T., Sinyashin O.G. Complexes of Sodium Pectate with Nickel for Hydrogen Oxidation and Oxygen Reduction in Proton-Exchange Membrane Fuel Cells. The results showed that the sodium pectate-nickel complexes exhibited promising catalytic activity for oxygen reduction. The researchers utilized electrochemical techniques, including a rotating disk electrode and the Koutecky-Levich equation, to investigate the kinetics of the oxygen electroreduction reaction. [Extracted from the article]

The esterification of oleic acid was applied in order to screen the suitability of a series of phosphotungstic-based Wells-Dawson types of compounds as potential catalysts in the heterogeneous transesterification of sunflower waste cooking oil. This test reaction indicated that the phosphotungstic Wells-Dawson heteropolyacid H6P2W18O62·xH2O, dispersed on titania oxide in a loading of 15 mg per m2 of oxide support (named 42% HPA/TiO2) and possessing exclusively Brønsted acid sites, was the most promising among the screened materials. In addition, the application of a nonlinear analysis methodology to find a surface that fits the specific activity of the oleic acid esterification with methanol at various temperatures, weights of catalyst, molar ratios of substrates, and stirring speeds, and also considering the active phase desorption out of the catalyst's surface, allowed determining the optimum operative conditions that were applied in the transesterification of the waste cooking oil afterwards. The transesterification of the waste cooking oil at 60 °C and 1:9 WCO: methanol molar ratio in a batch reactor under stirring at 650 rpm for 3 h, catalyzed with 0.25 wt% of 42% HPA/TiO2 (20.0 g of oil and 49.6 mg of catalyst), presents 74.6% of conversion of glycerides and 74.4% yield towards fatty acid methyl esters. The catalyst was recovered and reused several times, maintaining a fairly constant catalytic performance. [ABSTRACT FROM AUTHOR]

The main challenge in separating REEs through hydrometallurgical processes is their chemical similarities. Despite the literature widely presenting the possibilities for organic extractants, there is a lack of evaluation of the structures formed between the REEs and the extractants. The present study aimed to evaluate different extractants (neutral, anionic, and acid extractants) for separating La, Y, and Nd. The extraction efficiencies were evaluated, and the structure investigation was carried out in FT-IR. From the results obtained, it is clear that the extraction order is Alamine 336 <<< Cyanex 272 < Cyanex 923, where both acid extractants were more selective for Y than for La and Nd. The extraction achieved 99% at pH 5.0 in nitric acid media, and a Y/La ratio of 2 and a Y/Nd ratio of 4 using Cyanex 923. The present study also elucidated the organometallic complexation between Cyanex 923 and Cyanex 272 with Y and La, which may improve separation processes to obtain critical metals from primary and secondary sources. [ABSTRACT FROM AUTHOR]

In this work, a new hydrophobic deep eutectic solvent (HDES) based on trioctylphosphine oxide and di-(2-ethylhexyl)phosphoric acid was obtained. The formation of HDES was confirmed by NMR and FT-IR spectroscopy. The physical properties of the synthesized HDES were studied, density, dynamic viscosity, refractive index in the range of 15–60 °C, and phase diagram. The possibility of extraction of Co(II) and Al(III) ions from nitrate aqueous solutions was studied. The regularities of the interfacial distribution of metal ions were studied depending on the time of the extraction process, the ratio of components in HDES and pH of the aqueous phase. It has been shown that this HDES can be used for the selective extraction of metal ions. [ABSTRACT FROM AUTHOR]

1,4- and 1,2-additons of secondary phosphine oxides to (1R)-myrtenal and (1S)-myrtanal were evaluated as potential routes to P,C-stereogenic phosphine oxides bearing additional hydroxyl or aldehyde functions. 1,4-Additions of racemic secondary phosphine oxides to (1R)-myrtenal were found to offer moderate to good stereoselectivity which shows some promise for utility in kinetic resolution processes, especially at lower conversions. In case of 1,2-additions making the process doubly asymmetric by using an enantiomerically pure secondary phosphine oxide as substrate turned out to be practical. The stereochemical course of the addition reactions under study is presented. The P-resolved 1,2-addition products were demonstrated to undergo facile reduction by BH3 at room temperature leading to the formation of the corresponding α-hydroxyphosphine-boranes with clean inversion of configuration at the P-centre. All P,C-stereogenic phosphine oxides and boranes that were isolated in the form of a single diastereoisomer were assigned their absolute configurations by means of X-ray crystallography and/or 2D NMR spectral techniques. [ABSTRACT FROM AUTHOR]

Poly (N-vinylcaprolactam) is a polymer that is biocompatible, water-soluble, thermally sensitive, non-toxic, and nonionic. In this study, the preparation of hydrogels based on Poly (N-vinylcaprolactam) with diethylene glycol diacrylate is presented. The N-Vinylcaprolactam-based hydrogels are synthesised by using a photopolymerisation technique using diethylene glycol diacrylate as a crosslinking agent, and Diphenyl (2, 4, 6-trimethylbenzoyl) phosphine oxide as a photoinitiator. The structure of the polymers is investigated via Attenuated Total Reflectance–Fourier Transform Infrared Spectroscopy. The polymers are further characterised using differential scanning calorimetry and swelling analysis. This study is conducted to determine the characteristics of P (N-vinylcaprolactam) with diethylene glycol diacrylate, including the addition of Vinylacetate or N-Vinylpyrrolidone, and to examine the effects on the phase transition. Although various methods of free-radical polymerisation have synthesised the homopolymer, this is the first study to report the synthesis of Poly (N-vinylcaprolactam) with diethylene glycol diacrylate by using free-radical photopolymerisation, using Diphenyl (2, 4, 6-trimethylbenzoyl) phosphine oxide to initiate the reaction. FTIR analysis shows that the NVCL-based copolymers are successfully polymerised through UV photopolymerisation. DSC analysis indicates that increasing the concentration of crosslinker results in a decrease in the glass transition temperature. Swelling analysis displays that the lower the concentration of crosslinker present in the hydrogel, the quicker the hydrogels reach their maximum swelling ratio. [ABSTRACT FROM AUTHOR]

In order to obtain sulfur-containing organophosphorus compounds that are promising as extractants of heavy metals, the interaction of elemental phosphorus and sulfur with alkyl bromides catalyzed using strong bases was studied. According to the task, the reaction of non-toxic and non-flammable red phosphorus with alkyl bromides under conditions of phase transfer catalysts (PTC), followed by the introduction of elemental sulfur into the reaction medium, were studied. It is shown that alkyl bromides interact with red phosphorus when heated (95–105 °C, 5–8 h) under conditions of phase transfer catalysts (PTC) in a two-phase system: a 60% aqueous solution of KOH-toluene-benzyltriethylammonium chloride (BTEAC) forming a mixture of organophosphorus compounds along with alkylphosphines (57–60%), are the main reaction products; alkylphosphine oxides are also formed (40–43%). The introduction of elemental sulfur (solution in toluene) at the final stage of the process into the reaction mass cooled to 40–60 °C leads to the expected alkylphosphine sulfides, which are the result of the interaction of alkylphosphines with sulfur. The formation of complex mixtures of products prevents the release of target alkylphosphine sulfides in individual form. However, the synthesized mixture of alkylphosphine sulfides and alkylphosphine oxides without separation into individual components is promising for studying its extraction properties in relation to heavy metals. Testing of the extraction properties of synthesized mixtures of alkylphosphine sulfides and alkylphosphine oxides in relation to heavy metals (Ni, Co, Zn, Pb) and noble metals (Ag) showed that the resulting mixtures of tertiary phosphine oxides and phosphine sulfides are highly effective extractants. The degree of extraction in relation to Ni, Co, Zn, and Pb varies from 99.90 to 99.99%, and for Ag from 99.56 to 99.59%. [ABSTRACT FROM AUTHOR]

Heterocycles functionalized with pentavalent phosphorus are of great importance since they include a great variety of biologically active compounds and pharmaceuticals, advanced materials, and valuable reactive intermediates for organic synthesis. Significant progress in synthesis of P(O)R2-substituted six-membered heterocycles has been made in the past decade. This review covers the synthetic strategies towards aromatic monocyclic six-membered N-heterocycles, such as pyridines, pyridazines, pyrimidines, and pyrazines bearing phosphonates and phosphine oxides, which were reported from 2012 to 2022. [ABSTRACT FROM AUTHOR]

A series of complexes [Cu2X2(Pic3PO)2] (X = Cl, Br, I) based on tris(pyridin-2-ylmethyl)phosphine oxide (Pic3PO) has been synthesized. At 298 K, these compounds exhibit thermally activated delayed fluorescence (TADF) of 1(M+X)LCT type with λmax varying from 485 to 545 nm, and quantum efficiency up to 54%. In the TADF process, the halide effect appears as the emission intensification and bathochromic shift of λmax in the following order X = I < Br < Cl. Upon X-ray irradiation, the title compounds emit radioluminescence, the emission bands of which have the same shape as those at TADF, thereby meaning a similar radiative excited state. By contrast to TADF, the halide effect in the radioluminescence is reversed: its intensity grows in the order X = Cl < Br < I, since heavier atoms absorb X-rays more efficiently. These findings essentially contribute to our knowledge about the halide effect in the photo- and radioluminescent Cu(I) halide emitters. [ABSTRACT FROM AUTHOR]

The present work demonstrates the optimization of the ligand structure in the series of bis(phosphine oxide) and β-ketophosphine oxide representatives for efficient coordination of Tb3+ and Eu3+ ions with the formation of the complexes exhibiting high Tb3+- and Eu3+-centered luminescence. The analysis of the stoichiometry and structure of the lanthanide complexes obtained using the XRD method reveals the great impact of the bridging group nature between two phosphine oxide moieties on the coordination mode of the ligands with Tb3+ and Eu3+ ions. The bridging imido-group facilitates the deprotonation of the imido- bis(phosphine oxide) ligand followed by the formation of tris-complexes. The spectral and PXRD analysis of the separated colloids indicates that the high stability of the tris-complexes provides their safe conversion into polystyrenesulfonate-stabilized colloids using the solvent exchange method. The red Eu3+-centered luminescence of the tris-complex exhibits the same specificity in the solutions and the colloids. The pronounced luminescent response on the antibiotic ceftriaxone allows for sensing the latter in aqueous solutions with an LOD value equal to 0.974 μM. [ABSTRACT FROM AUTHOR]

Ligands play a critical role in promoting transition-metal-catalyzed C–H activation reactions. However, owing to high sensitivity of the reactivity of C–H activation to metal catalysts, the development of effective ligands has been a formidable challenge in the field. Rh(I)-catalyzed C–H cyclization of benzimidazoles with alkenes has been faced with low reactivity, often requiring very harsh conditions. To address this challenge, a phosphine oxide-enabled Rh(I)–Al bimetallic catalyst was developed for the reaction, significantly promoting the reactivity and allowing the reaction to run at 120 °C with up to 97% yield. [ABSTRACT FROM AUTHOR]

The present work describes an efficient reaction of electrochemical phosphorylation of phenylacetylene controlled by the composition of catalytic nanoparticles based on non-noble-metals. The sought-after products are produced via the simple synthetic protocol based on room temperature, atom-economical reactions, and silica nanoparticles (SNs) loaded by one or two d-metal ions as nanocatalysts. The redox and catalytic properties of SNs can be tuned with a range of parameters, such as compositions of the bimetallic systems, their preparation method, and morphology. Monometallic SNs give phosphorylated acetylene with retention of the triple bond, and bimetallic SNs give a bis-phosphorylation product. This is the first example of acetylene and phosphine oxide C-H/P-H coupling with a regenerable and recyclable catalyst. [ABSTRACT FROM AUTHOR]

The synthesis of novel phosphorus-containing telomers (P-telomers) was conducted via a solution-free UV-initiated telomerization process of butyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate, and styrene, different phosphorus telogens (dimethyl phosphite (DMPh), dibutyl phosphite (DBPh), diphenyl phosphite (DPPh) or dibutyl phosphate (DBP)), and a radical photoinitiator-acylphosphine oxide (APO). The course of the UV-phototelomerization process was monitored by photo-DSC and the chemical structures of telomers were assessed by FTIR. Final UV-photocurable varnish compositions consisted of prepared P-telomer syrups, crosslinking monomer (pentaerythritol triacrylate; PETIA), and a radical UV-photoinitiator (α-hydroxyalkylphenone, HAP). The influence of P- telomers on the optical and mechanical features of coatings was investigated. Relatively the highest hardness and satisfactory scratch values, as well as water and solvent resistance, were observed for varnish based on DMPh-telomers. While the strongest adhesive bond to a glass substrate was reported for DPPh-telomers. It is worth pointing out that the P-telomers did not affect the gloss values of varnishes in comparison to the telomer-free reference sample. [ABSTRACT FROM AUTHOR]

Deprotonation of a bis(amino)phosphane H2L = PhP(HNBtd)2 bearing a heterocyclic Btd = 2,1,3-benzothiadiazol-4-yl substituents at nitrogen atoms by silylamides LiNTms2 and Y(NTms2)3 (Tms = trimethylsilylamide) results in lithium and yttrium complexes with the deprotonated HL– and L2– forms as κ2-N and κ4-N chelating ligands. A binuclear complex [LiHL]2 was crystallized from Et2O, and was shown to reversibly dissociate in thf (tetrahydrofuran) with the NH(soln)–PH(crystal) tautomeric shift; the compound [Li2L] was spectroscopically characterized. Yttrium readily forms stable bis-ligand complexes [YL2]– and [YL(HL)]. In the latter, the H atom in HL resides on phosphorus; the coordination sphere remains accessible to another ligands, and it was crystallized as [{YL(HL)}2(µ-dioxane)] species (YN8O coordination). In the former complex, the coordination sphere was saturated (YN8) by closer bound ligands; it was crystallized as a salt with [Li(thf)4]+. The monoligand complex could not be cleanly obtained in a 1:1 reaction of H2L and Y(NTms2)3, and was only crystallographically characterized as a dimer [YL(NTms)2]2. Partial oxidation of the central P atom with the formation of phosphine-oxide ligands PhP(O)(NBtd)2– was observed. They co-crystallize in the same position as non-oxidized ligands in [YL2]– and [YL(NTms2)]2 species and participate in bonding between two units in the latter. TD-DFT calculations reveal that main transitions in the visible region of electronic spectra correspond to the charge transfer bands mostly associated with the orbitals located on Btd fragments. [ABSTRACT FROM AUTHOR]

To separate the long-lived minor actinides (MA = Am, Cm) from high-level liquid waste (HLLW), we have been studying an advanced separation process via selective adsorption that uses minimal amounts of organic solvent and compact equipment. The process consists of two separation columns packed with a CMPO (octyl(phenyl)-N,N-diisobutylcarbamoyl-methyl phosphine oxide) adsorbent for elemental group separation and a soft-donor named the R-BTP (2,6-bis-(5,6-dialkyl-1,2,4-triazine-3-yl) pyridine) adsorbent for the isolation of MA from lanthanides (Ln). In this work, the effects of nitrate ion (NO3−) on the adsorption behavior of Am(III) and a typical fission product Ln(III) onto the isoBu-BTP/SiO2-P adsorbent were studied experimentally. Then, the desorption properties of the adsorbed element were examined using different eluting agents. A hot test for the separation of MA from the fission product Ln in a genuine MA containing effluent from the irradiated MOX-fuel treatment process was carried out using a nBu-BTP/SiO2-P packed column. It was found that the separation factor between Am(III) and Ln(III)-FP is over 100 in the measured 0.5–4 M NO3−. The adsorbed elements could be effectively eluted off using a complexing agent such as DTPA or pure water. Complete separation between MA and Ln was achieved in the column results, indicating that the proposed MA separation process is feasible in principle. [ABSTRACT FROM AUTHOR]

Reaction of [YbCp2(dme)] (Cp = cyclopentadienyl, dme = 1,2 dimethoxyethane) with bis(diphenylphosphano)methane dioxide (H2dppmO2) leads to deprotonation of the ligand H2dppmO2 and oxidation of ytterbium, forming an extremely air-sensitive product, [YbIII(HdppmO2)3] (1), a six-coordinate complex with three chelating (OPCHPO) HdppmO2 ligands. Complex 1 was also obtained by a redox transmetallation/protolysis synthesis from metallic ytterbium, Hg(C6F5)2, and H2dppmO2. In a further preparation, the reaction of [Yb(C6F5)2] with H2dppmO2, not only yielded compound 1, but also gave a remarkable tetranuclear cage, [Yb4(µ-HdppmO2)6(µ-F)6] (2) containing two [Yb(µ-F)]2 rhombic units linked by two fluoride ligands and the tetranuclear unit is encapsulated by six bridging HdppmO2 donors. The fluoride ligands of the cage result from C-F activation of pentafluorobenzene and concomitant formation of p-H2C6F4 and m-H2C6F4, the last being an unexpected product. [ABSTRACT FROM AUTHOR]

Two unique structures were isolated from the phosphorylation reaction of 10H-phenothiazine. The 5,5-dimethyl-2-(10H-phenothiazin-10-yl)-1,3,2-dioxaphosphinane 2-oxide (2a) illustrates the product of N-phosphorylation of phenothiazine. Moreover, a potential product of 2a instability, a thiophosphoric acid 2b, was successfully isolated and structurally characterized. Molecule 2a, similarly to sulfoxide derivative 3, possesses interesting phosphorescence properties due to the presence of d-pπ bonds. The X-ray, NMR, and DFT computational studies indicate that compound 2a exhibits an anomeric effect. Additionally, the syntheses of selected symmetrical and unsymmetrical pyridine-embedded phenazines were elaborated. To compare the influence of phosphorus and sulfur atoms on the structural characteristics of 10H-phenothiazine derivatives, the high-quality crystals of (4a,12a-dihydro-12H-benzo[5,6][1,4]thiazino[2,3-b]quinoxalin-12-yl)(phenyl)methanone (1) and selected phenazines 5,12-diisopropyl-3,10-dimethyldipyrido[3,2-a:3′,2′-h]phenazine (5) and 5-isopropyl-N,N,3-trimethylpyrido[3,2-a]phenazin-10-amine (6a) were obtained. The structures of molecules 1, 2a, 2-mercapto-5,5-dimethyl-1,3,2-dioxaphosphinane 2-oxide (2b), 3,7-dinitro-10H-phenothiazine 5-oxide (3), 5 and 6a were determined by single-crystal X-ray diffraction measurements. [ABSTRACT FROM AUTHOR]

The aim of this research was to compare the biomechanical properties of experimental composites containing a classic photoinitiating system (camphorquinone and 2-(dimethylami-no)ethyl methacrylate) or diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO) as a photoinitiator. The produced light-cured composites consisted of an organic matrix-Bis-GMA (60 wt.%), TEGDMA (40 wt.%) and silanized silica filler (45 wt.%). Composites contained 0.27; 0.5; 0.75 or 1 wt.% TPO. Vickers hardness, microhardness (in the nanoindentation test), diametral tensile strength, resistance to three-point bending and the CIE L* a* b* colorimetric analysis was performed with each composite produced. The highest average Vickers hardness values were obtained for the composite containing 1 wt.% TPO (43.18 ± 1.7HV). The diametral tensile strength remains on regardless of the type and amount of photoinitiator statistically the same level, except for the composite containing 0.5 wt.% TPO for which DTS = 22.70 ± 4.7 MPa and is the lowest recorded value. The highest average diametral tensile strength was obtained for the composite containing 0.75 wt.% TPO (29.73 ± 4.8 MPa). The highest modulus of elasticity characterized the composite containing 0.75 wt.% TPO (5383.33 ± 1067.1 MPa). Composite containing 0.75 wt.% TPO has optimal results in terms of Vickers hardness, diametral tensile strength, flexural strength and modulus of elasticity. Moreover, these results are better than the parameters characterizing the composite containing the CQ/DMAEMA system. In terms of an aesthetic composite containing 0.75 wt.%. TPO is less yellow in color than the composite containing CQ/DMAEMA. This conclusion was objectively confirmed by test CIE L* a* b*. [ABSTRACT FROM AUTHOR]

A literature survey of the P–C coupling reactions of 1,4-and 1,2-bromo-iodobenzenes with diphenylphosphine oxide or diethyl phosphite under different conditions comprising Pd-, Ni-, or Cu-catalysis revealed that, depending on the experimental details, the yields of the corresponding >P(O)-bromobenzenes were rather diverse and occasionally contradicting. Therefore, the reactivity of a series of 1,4-, 1,3- and 1,2-dibromo- and bromo-iodobenzenes with the above mentioned P-reagents was evaluated under the "P-ligand-free" microwave (MW)-assisted conditions elaborated by us. Starting from dibromobenzenes and iodo-bromoarenes, practical and competent syntheses were developed for phosphonoyl- and phosphinoyl-bromoarenes, and, in a few instances, for arenes with two P-functions. The cheaper dibromobenzenes may be substituted for the bromo-iodo derivatives. In all, 12 products were prepared in yields of 45–82%. They were fully characterized. The method described does not require the use of traditional P-ligands. [ABSTRACT FROM AUTHOR]

Conventional Staudinger reductions of organic azides are sluggish with aryl or bulky aliphatic azides. In addition, Staudinger reduction usually requires a large excess of water to promote the decomposition of the aza-ylide intermediate into phosphine oxide and amine products. To overcome the challenges above, we designed a novel triaryl phosphine reagent 2c with an ortho-SO2NH2 substituent. Herein, we report that such phosphine reagents are able to mediate the Staudinger reduction of both aryl and alkyl azides in either anhydrous or wet solvents. Good to excellent yields were obtained in all cases (even at a diluted concentration of 0.01 M). The formation of B-TAP, a cyclic aza-ylide, instead of phosphine oxide, eliminates the requirement of water in the Staudinger reduction. In addition, computational studies disclose that the intramolecular protonation of the aza-ylide by the ortho-SO2NH2 group is kinetically favorable and responsible for the acceleration of Staudinger reduction of the aryl azides. [ABSTRACT FROM AUTHOR]

The current review is devoted to the achievements in the development of methods for the catalytic asymmetric synthesis of phosphonates containing a chiral center in the side chain. C-chiral phosphonates are widely represented among natural compounds with various biological activities as insecticides, herbicides, antibiotics, and bioregulators. Synthetic representatives of this class have found practical application as biologically active compounds. The review summarizes methods of asymmetric metal complex catalysis and organocatalysis as applied to such reactions as phospha-aldol reaction, two-component and three-component phospha-Mannich reaction, phospha-Michael reaction, as well as hydrogenation of unsaturated phosphonates and phosphine oxides, ketophosphonates, and iminophosphonates. Methods for the asymmetric hydride reduction of C=X phosphonates (X=O, S, NR) are also discussed in detail. The review presents updated literature reports, as well as original research by the author. [ABSTRACT FROM AUTHOR]

A Knoevenagel based redox-reaction promoted by intramolecular phosphine sources is presented for the first time. The influence of different diketones, aldehydes, bases and acids was investigated. The effects of different substituents were evaluated based on their electronical influence on the diketone structure. With the obtained results a mechanism is proposed, giving information about transition states formed during the reaction, which can lead to different products. This type of an internal redox transformation with a phosphine oxide moiety remaining in the molecule after the redox reaction represents a new type of reaction. [ABSTRACT FROM AUTHOR]

Titanium slags produced through ilmenite electric furnace smelting contain 60–80%TiO2, a vital titanium resource in the titanium industry. The processing and utilization of titanium slag is faced with many challenges, such as complex mineral structures, high requirements, severe environmental pollution, and heavy additives and energy consumption. This study aims to review the technologies for the processing and utilization of titanium slag. First, we analyze the characteristics of titanium slag from different regions. Then, we discuss in detail the methods for processing and using titanium slag. The progress in electric furnace titanium slag processing and utilization can be divided into two areas: the preparation of titanium dioxide and high-quality titanium-rich materials. These include H2SO4 leaching, HCl leaching, fluoride leaching, sulfur roasting–leaching, alkaline roasting–leaching, oxide roasting–leaching, oxidation and reduction roasting–leaching, phosphorylation roasting–leaching, and ammonia decomposition leaching. Further development of oxide roasting–leaching for the extraction of titanium from titanium slag is recommended. [ABSTRACT FROM AUTHOR]

α-Aminophosphonates, -phosphinates, and -phosphine oxides are a group of organophosphorus compounds that were investigated as extraction agents for rare earth (RE) metals and actinoids for the first time in the 1960s. However, more systematic investigations of their extraction properties towards REs and actinoids were not started until the 2010s. Indeed, recent studies have shown that these α-amino-functionalized compounds can outperform the commercial organophosphorus extraction agents in RE separations. They have also proven to be very efficient extraction and precipitation agents for recovering Th and U from RE concentrates. These actinoids coexist with REs in some of the commercially important RE-containing minerals. The efficient separation and purification of REs is becoming more and more important every year as these elements have a pivotal role in many existing technologies. If one also considers the facile synthesis of α-amino-functionalized organophosphorus extractants and precipitation agents, it is expected that they will be increasingly utilized in the extraction chemistry of REs and actinoids in the future. This review collates α-aminophosphonates, -phosphinates, and -phosphine oxides that have been utilized in the separation chemistry of REs and actinoids, including their most relevant synthetic routes and molecular properties. Their extraction and precipitation properties towards REs and actinoids are also discussed. [ABSTRACT FROM AUTHOR]

We report efficient synthetic methodologies for the preparation of 3-amino and 3-hydroxy 3-pyrrolin-2-ones (unsaturated γ-lactams) through a multicomponent reaction of amines, aldehydes and acetylene or pyruvate derivatives. The densely substituted γ-lactam substrates show in vitro cytotoxicity, inhibiting the growth of the carcinoma human tumor cell lines RKO (human colon epithelial carcinoma), SKOV3 (human ovarian carcinoma) and A549 (carcinomic human alveolar basal epithelial cell). In view of the possibilities for the diversity of the substituents that offer a multicomponent, synthetic methodology, an extensive structure–activity profile is presented. In addition, the bioisosteric replacement of the flat ester group by a tetrahedral phosphonate or phosphine oxide moiety in γ-lactam substrates leads to increased growth inhibition activity. Cell morphology analysis and flow cytometry assays indicate that the main pathway by which our compounds induce cytotoxicity is based on the activation of the intracellular apoptotic mechanism. [ABSTRACT FROM AUTHOR]

The thermal and calorimetric characterizations of polymethyl methacrylate-based polymers are reported in this paper. The modifying groups incorporated the phosphorus atom in various chemical environments, including oxidation states of III, or V. Both additive and reactive strategies were employed, where the loading of phosphorus was kept at 2 wt% in all cases. The plaques, obtained through the bulk polymerization route, were subjected to a variety of spectroscopic, thermal and combustion techniques. The results showed that the different modifying groups exerted varying nature, degrees and modes of combustion behaviors, which also included in some cases an additive, and even an antagonistic effect. In the case of covalently-bound phosphonate groups, early cracking of the pendent ester moieties was shown to produce phosphoric acid species, which in turn can act in the condensed phase. For the additives, such as phosphine and phosphine oxide, limited vapor-phase inhibition can be assumed to be operative. [ABSTRACT FROM AUTHOR]

It was recently reported that a (2-hydroxybenzyl)phosphine oxide (2-HOBPO) can serve as a phosphorus-centered catalyst for the stereo-invertive coupling of aliphatic alcohols and acidic pronucleophiles (akin to a Mitsunobu reaction, but without additional reagents). Herein, we report an improved synthesis, which provides direct access to systematically varied 2-HOBPOs in a single step from commercially available precursors (salicylaldehydes and secondary phosphines). The efficiency and generality of the synthetic method enabled limited structure–activity relationship (SAR) studies, from which it was determined that substituents on both the phenolic and phosphine oxide portions can exert significant influence on the turnover frequency (TOF) of each catalyst. Importantly, for all catalytically active 2-HOBPOs examined, the molecularity of catalyst in the rate law of the alcohol coupling was determined to be <1. Thus, for high catalyst loadings, differences in catalytic activity between 2-HOBPOs appear to be dominated by differences in catalytic auto-inhibition, while for low catalyst loadings, differences are attributed to inherent differences in the energetic span of the catalytic cycle, ignoring off-cycle species, in good agreement with density functional theory (DFT) modeling at the ωB97X-D/6-311G(d,p) level. [ABSTRACT FROM AUTHOR]

Aim: The purpose of this study was to evaluate the mechanical properties of an experimental self-healing dental composite model (SHDC) composed of SiO2 nanoparticles with varying percentages of triethylene glycol dimethacrylate (TEGDMA) monomer and N,N-dihydroxyethyl-p-toluidine (DHEPT) amine microcapsules. Materials and methods: Microcapsules were prepared by in-situ polymerisation of PUF shells, as explained in our previous work. The model SHDC included bisphenol A glycidyl dimethacrylate (Bis-GMA:TEGDMA) (1:1), 1 wt% phenyl bis(2,4,6-trimethylbenzoyl) phosphine oxide (BAPO), 0.5 wt% benzoyl peroxide (BPO) catalyst, 20 wt% silanised silica dioxide (SiO2) (15 nm) and (0, 2.5, 5, 7.5, 10 wt%) of microcapsules (120 ± 45 μm). Light transmission, hardness, degree of conversion (DC), flexural strength and elastic modulus of the SHDC model were measured. Results: The degree of conversion of the SHDC ranged from 73 to 76% 24 h after polymerisation. Hardness measurements ranged from 22 to 26 VHN (p > 0.05); however, the flexural strength was adversely affected from 80 to 55 MPa with increasing microcapsules of up to 10 wt% in the composites (p < 0.05). Conclusion: Only flexural strength decreased drastically ~30% with increasing microcapsules (>10 wt%) in the composites. All other measured properties were not significantly affected. Accordingly, we recommend a stronger composite material that could be created by increasing the filler content distribution in order to achieve a hybrid self-healing composite with enhanced mechanical properties. [ABSTRACT FROM AUTHOR]

In this work, graphite intercalation compounds (GICs) were synthesized using three different oxidizers: (NH4)2S2O8, K2S2O8, and CrO3 with and without P2O5 as a water-binding agent. Furthermore, the samples obtained were heat-treated at 800 °C. Specimens were characterized by optical microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), and scanning electron microscopy (SEM). The correlation between different characteristic parameters of the Raman analysis has shown that the use of CrO3 results in a much higher structural disorder compared to the products obtained using persulfate oxidizers. Narrowing the correlation set revealed that minimal defect concentration can be reached by using K2S2O8, while the use of (NH4)2S2O8 causes a slightly higher concentration of defects. It was also established that the additional use of P2O5 can help to achieve more effective intercalation and has a positive effect on the formation of the stage I GIC phase. After heat treatment, the intercalated products mostly return to a graphite-like structure; however, the samples obtained with CrO3 stand out with the most significant changes in their surface morphology. Therefore, analysis suggests that GICs obtained using persulfate oxidizers and P2O5 could be a candidate to produce high-quality graphene or graphene oxide. [ABSTRACT FROM AUTHOR]

The single crystal structure of bis(2,4,6-trimethylphenyl)phosphine oxide has been determined. All interatomic distances and angles can be considered normal. The aryl substituents adopt an intermediate configuration when compared to both sterically unhindered (e.g., diphenylphosphine oxide) and congested (e.g., bis(2,4,6-tri-tert-butylphenyl)phosphine oxide) secondary phosphine oxides, illustrating the influence of steric congestion on the molecular structure. [ABSTRACT FROM AUTHOR]

Water contamination with harmful arsenic compounds represents one of the most serious calamities of the last two centuries. Natural occurrence of the toxic metal has been revealed recently for 21 countries worldwide; the risk of arsenic intoxication is particularly high in Bangladesh and India but recently also Europe is facing similar problem. Liquid membranes (LMs) look like a promising alternative to the existing removal processes, showing numerous advantages in terms of energy consumption, efficiency, selectivity, and operational costs. The development of different LM configurations has been a matter of investigation by several researching groups, especially for the removal of As(III) and As(V) from aqueous solutions. Most of these LM systems are based on the use of phosphine oxides as carriers, when the metal removal is from sulfuric acid media. Particularly promising for water treatment is the hollow fiber supported liquid membrane (HFSLM) configuration, which offers high selectivity, easy transport of the targeted metal ions, large surface area, and non-stop flow process. The choice of organic extractant(s) plays an essential role in the efficiency of the arsenic removal. Emulsion liquid membrane (ELM) systems have not been extensively investigated so far, although encouraging results have started to appear in the literature. For such LM configuration, the most relevant step toward efficiency is the choice of the surfactant type and its concentration. [ABSTRACT FROM AUTHOR]

Pd-catalyzed, site-selective mono-cross-coupling of substrates with two identical halo groups is a useful method for synthesizing substituted monohalogenated arenes. Such arenes constitute an important class of compounds, which are commonly identified as drug components and synthetic intermediates. Traditionally, these site-selective reactions have been realized in a "substrate-controlled" manner, which is based on the steric and electronic differences between the two carbon-halogen bonds of the substrate. Recently, an alternative strategy, "catalyst-controlled" site-selective cross-coupling, has emerged. In this strategy, the preferred reaction site of a dihaloarene can be switched, merely by changing the catalyst used. This type of selective reaction further expands the utility of Pd-catalyzed cross-coupling. In this review, we summarize the reported examples of catalyst-controlled site-selectivity switching in Pd-catalyzed cross-coupling of dihaloarenes. [ABSTRACT FROM AUTHOR]

Biocompatibility is important for the 3D printing of resins used in medical devices and can be affected by photoinitiators, one of the key additives used in the 3D printing process. The choice of ingredients must be considered, as the toxicity varies depending on the photoinitiator, and unreacted photoinitiator may leach out of the polymerized resin. In this study, the use of ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate (TPO-L) as a photoinitiator for the 3D printing of resin was considered for application in medical device production, where the cytotoxicity, colour stability, dimensional accuracy, degree of conversion, and mechanical/physical properties were evaluated. Along with TPO-L, two conventional photoinitiators, phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide (BAPO) and diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO), were considered. A total of 0.1 mol% of each photoinitiator was mixed with the resin matrix to prepare a resin mixture for 3D printing. The specimens were printed using a direct light processing (DLP) type 3D printer. The 3D-printed specimens were postprocessed and evaluated for cytotoxicity, colour stability, dimensional accuracy, degree of conversion, and mechanical properties in accordance with international standards and the methods described in previous studies. The TPO-L photoinitiator showed excellent biocompatibility and colour stability and possessed with an acceptable dimensional accuracy for use in the 3D printing of resins. Therefore, the TPO-L photoinitiator can be sufficiently used as a photoinitiator for dental 3D-printed resin. [ABSTRACT FROM AUTHOR]

Polyurea is an isocyanate derivative, and comprises the basis for a well-established class of polymeric aerogels. Polyurea aerogels are prepared either via reaction of multifunctional isocyanates with multifunctional amines, via reaction of multifunctional isocyanates and water, or via reaction of multifunctional isocyanates and mineral acids. The first method is the established one for the synthesis of polyurea, the third is a relatively new method that yields polyurea doped with metal oxides in one step, while the reaction of isocyanates with water has become the most popular route to polyurea aerogels. The intense interest in polyurea aerogels can be attributed in part to the low cost of the starting materials—especially via the water method—in part to the extremely broad array of nanostructural morphologies that allow study of the nanostructure of gels as a function of synthetic conditions, and in part to the broad array of functional properties that can be achieved even within a single chemical composition by simply adjusting the synthetic parameters. In addition, polyurea aerogels based on aromatic isocyanates are typically carbonizable materials, making them highly competitive alternatives to phenolic aerogels as precursors of carbon aerogels. Several types of polyurea aerogels are already at different stages of commercialization. This article is a comprehensive review of all polyurea-based aerogels, including polyurea-crosslinked oxide and biopolymer aerogels, from a fundamental nanostructure–material properties perspective, as well as from an application perspective in thermal and acoustic insulation, oil adsorption, ballistic protection, and environmental cleanup. [ABSTRACT FROM AUTHOR]

Phosphinines and donor-substituted phosphinines are of recent interest due to their use in homogeneous catalysis. In this article, a Pd(II) bis(phosphinine) complex was characterised and phosphorus–selenium coupling constants were used to assess the donor properties of the diphenylphosphine substituents of phosphinine ligands to promote their further use in catalysis. The selenation of 2,5-bis(diphenylphosphino)-3,6-dimethylphosphinine (5) and 2-diphenylphosphino-3-methyl-6-trimethylsilylphosphinine (6) gave the corresponding phosphine selenides 8 and 9, respectively, leaving the phosphinine ring intact. Multinuclear NMR spectroscopy, mass spectrometry and single crystal X-ray diffraction confirmed the oxidation of all the diphenylphosphine substituents with 1JP-Se coupling constants determined to be similar to SePPh3, indicating that the phosphinine rings were electronically similar to phenyl substituents. Solutions of 6 were found to react with oxygen slowly to produce the phosphine oxide 10 along with other by-products. The reaction of [bis{3-methyl-6-(trimethylsilyl)phosphinine-2-yl}dimethylsilane] (4) with [PdCl2(COD)] gave the chelating dichloropalladium(II) complex, as determined by multinuclear NMR spectroscopy, mass spectrometry and an elemental analysis. The molecular structure of the intermediate 2 in the formation of 4,6-di(tert-butyl)-1,3,2-diazaphosphinine (3) was also determined, which confirmed the structure of the diazaphosphacycle P(Cl){N=C(tBu)CH=C(tBu)-N(H)}. [ABSTRACT FROM AUTHOR]

The optical properties of indium phosphide (InP) quantum dots (QDs) are significantly influenced by their surface native oxides, which are generally removed by treating InP cores with hydrofluoric acid (HF). Besides the harmful health effects of HF, its etching may cause over-etching or QD size broadening, and surface oxidation can also reoccur rapidly. In the present study, a safer bifunctional metal oleate treatment was developed to simultaneously remove the surface oxide layer and passivate the surface defects for aminophosphine-based InP QDs. Compared to conventional HF etching, the bifunctional metal oleate was able to more efficiently remove the surface oxide of InP cores and effectively preserve the oxide-free surface, leading to a 20% narrower photoluminescence (PL) bandwidth after growing a ZnSe/ZnS shell. The metal oleate treatment is thus considered a greener and safer post-synthetic method to remove InP surface oxide and provide additional passivation to improve the optical properties of aminophosphine-based InP QDs, which could have potential in industrial mass production. [ABSTRACT FROM AUTHOR]

The enzyme-catalyzed monoacetylation of prochiral bis (2-hydroxymethylphenyl)methylphosphine and bis (2-hydroxymethylphenyl)phenylphosphine and their P-sulfides gave, in one single step, as a result of desymmetrisation, the corresponding monoacetates in moderate yields and with an enantiomeric excess of 16 to 98%, depending on the substrate structure and enzyme applied. The absolute configurations of the selected products were determined by a chemical correlation. This led to the conclusion that, in the case of phosphines, phosphine oxides and phosphine sulfides enzymes preferentially produce compounds of the same spatial arrangement. The new compounds obtained will be transformed into chiral catalysts/ligands. [ABSTRACT FROM AUTHOR]

The new phosphine oxide compound, (dimethylphosphoryl)methanaminium perchlorate, dpmaHClO4 (1), was synthesized by the reaction of (dimethylphosphoryl) methanamine (dpma) with concentrated perchloric acid. (Dimethylphosphoryl)methanaminium perchlorate (dimethylphosphoryl)methanamine solvate, dpmaHClO4•dpma (2) was obtained by the slow evaporation of an equimolar methanolic solution of 1 and dpma at room temperature. For both compounds, single-crystal X-ray structures, IR and Raman spectra are reported. The assignment of the spectroscopic data were supported by quantum chemical calculations at the B3LYP/6-311G(2d,p) level of theory. In 1, the dpmaH cations form polymeric, polar double-strands along [010] by head to tail connections via N--H--O hydrogen bonds. The perchlorate anions are located between these strands attached by one medium strong and two weaker un-bifurcated hydrogen bonds (monoclinic, centrosymmetric space group C2/c, a = 17.8796(5) Å, b = 5.66867(14) Å, c = 17.0106(5) Å, β = 104.788(3)°, V = 1666.9(1) ų, Z = 8, T = 293 K, R(F) [I > 2σ(I)] = 0.0391, wR(F²) [all] = 0.1113). In 2, besides the N--H--O hydrogen bonds, medium strong N--H--N hydrogen bonds are present. One dpmaH cation and the neutral dpma molecule are connected head to tail by two N--H--O hydrogen bonds forming a monocationic cyclic unit. These cyclic units are further connected by N--H--O and N--H--N hydrogen bonds forming polymeric, polar double-strands along [001]. The perchlorate anions fill the gaps between these strands, and each [ClO4]-- anion is weakly connected to the NH2 group by one N--H--O hydrogen bond (orthorhombic, non-centrosymmetric space group Pca21 (No. 29), a = 18.5821(5) Å, b = 11.4320(3) Å, c = 6.89400(17) Å, V = 1464.50(6) ų, Z = 4, T = 100 K, R(F) [I > 2σ(I)] = 0.0234, wR(F²) [all] = 0.0575). Both structures are structurally related, and their commonalities are discussed in terms of a graph-set analysis. [ABSTRACT FROM AUTHOR]

The Kabachnik-Fields (phospha-Mannich) reaction involving the condensation of primary or secondary amines, oxo compounds (aldehydes and ketones) and >P(O)H species, especially dialkyl phosphites, represents a good choice for the synthesis of a-aminophosphonates that are of significant importance due to their biological activity. In general, these three-component reactions may take place via an imine or an a-hydroxy-phosphonate intermediate. The monitoring of a few Kabachnik-Fields reactions by in situ Fourier transform IR spectroscopy has indicated the involvement of the imine intermediate that was also justified by theoretical calculations. The Kabachnik-Fields reaction was extended to >P(O)H species, comprising cyclic phosphites, acyclic and cyclic H-phosphinates, as well as secondary phosphine oxides. On the other hand, heterocyclic amines were also used to prepare new α-amino phosphonic, phosphinic and phosphine oxide derivatives. In most cases, the synthesis under solvent-free microwave (MW) conditions is the method of choice. It was proved that, in the cases studied by us, there was no need for the use of any catalyst. Moreover, it can be said that sophisticated and environmentally unfriendly catalysts suggested are completely unnecessary under MW conditions. Finally, the double Kabachnik-Fields reaction has made available bis(phosphonomethyl)amines, bis(phosphinoxidomethyl)amines and related species. The bis(phosphinoxidomethyl)amines serve as precursors for bisphosphines that furnish ring platinum complexes on reaction with dichlorodibenzonitriloplatinum. [ABSTRACT FROM AUTHOR]

The reaction of diethyl α-oxoethylphosphonate and diethyl oxobenzylphosphonate with diethyl phosphite, dimethyl phosphite, and diphenylphosphine oxide affords, depending on the substrates and conditions (nature and quantity of the amine catalyst, temperature, and solvent), the Pudovik adduct and/or the corresponding >P(O)–CH–O–P(O)< product formed by rearrangement. The nature of the substituent on the central carbon atom (a methyl or phenyl group) influences the inclination for the rearrangement. The asymmetric products (either adducts or rearranged species) with different P(O)Y functions (Y = RO or Ph) exhibit interesting NMR features. [ABSTRACT FROM AUTHOR]

A new attempt to use a bifunctional interleaf for developing a novel structure–function-integrated composite with simultaneously improved interlaminar fracture toughness and atomic oxygen resistance was studied. The toughening mechanism and the atomic oxygen erosion property of the delaminated surfaces of the composites were examined. The bifunctional interleaf was prepared by blending a phosphorus-containing polymer and a thermoplastic polymer. After being interleaved, the mode I and mode II fracture toughness increased by 8.2% and 23.7% compared to the control sample, respectively. The toughness gains are much smaller than that of the only thermoplastic film-toughened composite because of the relative brittleness of the blend film. The atomic oxygen erosion rates of the mode I and mode II delamination surfaces decreased by 45.3% and 31.3% compared with the control, respectively. The carbon fibers on the irradiation surfaces are protected by a layer of phosphine oxide to prevent further erosion, and they were much less eroded, particularly for the mode I surface. In comparison, the erosion rates of the mode I and mode II surfaces of the toughened-only composite significantly increased by 83.6% and 107.2%, respectively, and the carbon fibers are seriously eroded. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) printing technology, specifically stereolithography (SLA) technology, has recently created exciting possibilities for the design and fabrication of sophisticated dosages for oral administration, paving a practical way to precisely manufacture customized pharmaceutical dosages with both personalized properties and sustained drug release behavior. However, the sustained drug release achieved in prior studies largely relies on the presence of hydrophilic excipients in the printing formulation, which unfortunately impedes the printability and formability of the corresponding printing formulations. The current study developed and prepared mini-sized oral pellets using the SLA technique and successfully accomplished a hydrophilic excipient-independent drug release behavior. With ibuprofen as the model drug, the customized photopolymerizable printing formulation included polyethylene glycol diacrylate (PEGDA) as a monomer and diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) as a photoinitiator. The produced mini-sized pellets were thoroughly investigated for various factors, including their printability, physical properties, microscopic features, drug content, and drug-release profiles. The drug release profiles from the printed pellets that were larger size (3 mm and 6 mm) followed the Ritger–Peppas model, demonstrating that the release was influenced by both the diffusion of the dissolved drug and by the erosion of the hydrophilic excipients (PEG400). The profiles from the smaller printed pellets (1 mm and 2 mm) followed first release kinetics, not only illustrating that the release was impacted only by drug diffusion, but also indicating that there is a size boundary between the dependent and independent hydrophilic excipients. These results could create practical benefits to the pharmaceutical industry in terms of the design and development personalized dosages using the SLA printing technique with controllable drug release by manipulating size alone. [ABSTRACT FROM AUTHOR]

In conventional steam cracking feedstocks, contaminants such as sulfur, phosphine, and heavy metal components, present in trace levels, are believed to affect coke formation on high temperature alloys. To gain an understanding of the role of phosphine coking rates on 25/35, CrNi and Al-containing reactor materials were determined in a plug flow reactor during cracking of a propane feedstock doped with ppb levels of PH3 in the presence of DMDS. The presence of phosphine decreased the asymptotic coking rates by more than 20%, while it had a smaller influence on the catalytic coking rate. The coking rate was more severely reduced for the 25/35 CrNi alloy in comparison to the Al-containing alloy. The ppm levels of phosphine did not affect the olefin yields nor the production of undesired carbon monoxide. The morphology of the coked alloys were studied using an off-line Scanning Electron Microscope with Energy Dispersive X-ray detector (SEM with EDX) images of coked coupons. Two types of coke morphology are observed, i.e., filamentous coke with DMDS as an additive and globular coke in the presence of phosphine. The effect of phosphine on the material has a positive impact on the oxide scale homogeneity of 25/35 CrNi alloy, whereas the Al-containing alloy remained unchanged. [ABSTRACT FROM AUTHOR]

An experimental and a theoretical study on the so far less investigated Cu(I) salt-catalyzed Hirao reaction of iodobenzene and diarylphosphine oxides (DAPOs) revealed that Cu(I)Br or Cu(I)Cl is the most efficient catalyst under microwave irradiation. The optimum conditions included 165 °C and a 1:2 molar ratio for DAPOs and triethylamine. The possible ligations of Cu(I) were studied in detail. Bisligated P---Cu(I)---P (A), P---Cu(I)---N (B) and N---Cu(I)---N (C) complexes were considered as the catalysts. Calculations on the mechanism suggested that complexes A and B may catalyze the P–C coupling, but the latter one is more advantageous both according to experiments and calculations pointing out the Cu(I) → Cu(III) conversion in the oxidative addition step. The P–C coupling cannot take place with PhBr, as in this case, the catalyst complex cannot be regenerated. [ABSTRACT FROM AUTHOR]