Phenylphosphine Oxide Research Articles

Facile Synthesis of Bis-Diphenylphosphine Oxide as a Flame Retardant for Epoxy Resins.

A phosphorus-containing compound, (oxybis(4,1-phenylene))bis(phenylphosphine oxide) (ODDPO), was successfully synthesized and used as a flame retardant for epoxy resin (EP). The results demonstrated that EP/ODDPO, containing 1.2 wt% phosphorus, achieved a vertical burning V-0 rating, with a limited oxygen index value of 29.2%, indicating excellent flame retardancy. Comprehensive evaluations revealed that ODDPO exhibited both gas-phase and condensed-phase flame-retardant effects on EP, with a particularly notable barrier effect. In addition, the incorporation of ODDPO had a minimal negative impact on the glass transition temperature (Tg) and thermal stability of the EP matrix. Compared to unmodified EP (EP-0), the Tg value and initial decomposition temperature of EP/ODDPO-1.2 decreased by only 7.6 °C and 10.0 °C, respectively. Moreover, the introduction of ODDPO significantly improved the hydrophobicity and water absorption resistance of epoxy materials, which is attributed to ODDPO's rigidity and symmetric structure, reducing water molecule permeation. Furthermore, the dielectric properties of ODDPO-modified EP samples were strengthened compared to EP-0, due to the ODDPO's symmetric structure reducing the polarity of the matrix. The above results indicated that ODDPO serves as an excellent flame retardant while enhancing other properties of the EP matrix, thereby contributing to the preparation and application of high-performance epoxy materials.

Preparation and characterization of UV-curable composite containing nano silica for glass-to-glass bonding

Glass is a transparent and geometrically ordered element in architecture. Glass bonding can be classified into adhesive, layered, and mechanical categories. One of the best bonding materials for glass applications is adhesive. The preparation and investigation of Ultraviolet (UV)-curable composites for glass-to-glass bonding is the goal of this research. The investigation focused on the effect of raw material type and weight percentage on mechanical properties. Epoxy acrylate resin was employed as an oligomer in this study. Trimethylolpropane triacrylate (TMPTA), tripropyleneglycol triacrylate (TPGDA), and pentaerythritol tetraacrylate (PETA) were used as monomers. As photoinitiators, were used bis (2,4,6 trimethylbenzoyl)-phenylphosphine oxide, hydroxycyclohexyl phenylketone, and 2,4,6-trimethylbenzoyl diphenyl phosphineoxide. Benzophenone, acrylic acid, nano silica, and trimethoxysilylpropyl methacrylate (TMSPMA) were used as the additives. The mechanical properties of the samples were studied using compressive and shear tests. The degree of conversion (DC) was obtained using Fourier transform infrared spectroscopy (FTIR). The mechanical behavior of the samples were measured as a function of temperature using dynamic mechanical thermal analysis (DMTA); and the distribution of nanoparticles was examined using scanning electron microscopy (SEM). The results showed that the sample containing 4 wt% nano silica, which also contained 24 wt% PETA and 7 wt% TMSPMA, has the best mechanical properties with 0.42 and 0.63 MPa compressive and shear strength, respectively. In the FTIR, was observed an increase of nano silica from the lowest (1 wt%) to the highest amount (5 wt%), the DC current decreased by 11 %. In the DMTA analysis, it was observed that an increase of nano silica from 1 to 5 wt%, the storage modulus increased by 41 %. The highest loss modulus and loss temperature were related to the samples containing 1 and 2 wt% nano silica with 221 MPa and 113.8 °C. Finally, the best distribution of nanoparticles was observed in the sample containing 1 wt% nano silica. In the SEM images, agglomeration of nanoparticles was seen in the sample containing 5 wt% nano silica.

Monolith-coated microcentrifuge tubes for the easy extraction of psychoactive substances from urine samples and liquid chromatography-tandem mass spectrometry determination

BackgroundSample extraction is one of the most critical steps in most of the analytical processes. Nowadays, there is a demand for simple approaches that can effectively extract and concentrate target analytes from complex matrices, like biofluids, with accurate and reliable results. ResultsA porous monolith of poly(methacrylic acid-co-ethylene glycol dimethacrylate) has been immobilized on the inner wall of a 2 mL commercial polypropylene microcentrifuge tube through radical photopolymerization, using bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide as radical initiator and 405 nm laser pointer activation. Photopolymerization parameters were adjusted to obtain a continuous and homogeneous polymer layer (0.16 mm wet polymer thickness and 31 mg dry polymer weight) in the inner tube surface. Extraction efficiency of twelve psychoactive substances was assessed by the evaluation of the effect of sample pH, extraction and desorption times, and desorption solvent volume. Moreover, matrix effect, reusability and stability of monolith-coated microcentrifuge tubes were studied. Sample extracts were measured by liquid chromatography-tandem mass spectrometry, providing limits of quantification (LOQ) from 0.2 to 2.7 μg L−1, recoveries from 80 to 118 %, relative standard deviations lower than 17 %, and a linear range from LOQ to 500 μg L−1. SignificanceThe proposed device is suitable for the easy and simple extraction of psychoactive substances from urine samples with a high portability, reduced solvent consumption, low cost, and low environmental impact.

Development of tetra glycidyl epoxy-based nanocomposites and analysis of its mechanical, XRD, EDS, and physical properties for high-performance applications

This research work presents an investigation on N, N, N’, N’-tetraglycidyl-4,4′-diaminodiphenylmethane containing epoxy nanocomposites to seek out its suitability to be employed in high-performance applications. The synthesis and characterization of this epoxy denoted as ‘A’ was done. The nano reinforcement polyhedral oligomeric silsesquioxane -amine-based represented as ‘N2′ was incorporated into the synthesized epoxy. Curing of the tetraglycidyl epoxy was finished with diaminodiphenylmethane and bis (3-aminophenyl) phenyl phosphine oxide curing agents marked as X and Y respectively. The mechanical, X-ray diffraction, energy dispersive spectroscopy, viscosity, epoxy equivalent weight, and gel permeation chromatography studies were disbursed and the results thus obtained are presented.

Development of paper-immobilized molecularly imprinted polymers by laser pointer activation for methamphetamine extraction with analysis by ion mobility spectrometry

A fast, simple, cheap, and versatile strategy has been proposed for the synthesis of paper-immobilized molecularly imprinted polymers (MIPs) by photoactivated bulk polymerization over a piece of nitrocellulose using a 405 nm laser pointer. Polymerization was carried out using a mixture of methacrylic acid and ethylene glycol dimethacrylate, using methamphetamine as template molecule and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide as radical initiator. After investigation of different polymerization parameters, the following experimental conditions were found to give best results: size of nitrocellulose strip (13.5 × 4.0 × 0.8 mm), type of porogen (acetonitrile), polymerization mixture volume (75 µL), and irradiation times (10 min). Experimental conditions (such as sample pH, extraction and desorption time, and type and volume of desorption solvent) were also adjusted for the extraction of methamphetamine using the proposed paper-MIP. Methamphetamine determination was carried out by ion mobility spectrometry providing a limit of detection of 14 µg L−1 and quantitative recoveries from 81 to 95% using spiked urine and oral fluid samples. The proposed paper-immobilized MIP device allows a simple and selective sample extraction procedure for the determination of methamphetamine in oral fluids and urine with a high portability, minimal solvent consumption, and reduced costs compared to other conventional approaches.

Soluble sulfonated polybenzimidazoles containing phosphine oxide units as proton exchange membranes

Sulfonated bis(4-methyl benzoate) phenylphosphine oxide (sBMPO) was synthesized by the sulfonation and esterification of bis(4-methylbenzoate)phenylphosphine oxide (BMPO).

Controlling Charge Accumulation Properties of Organic Light‐Emitting Diodes using Dipolar Doping of Hole Transport Layers

AbstractIt is demonstrated that dipolar doping of hole transport layers (HTLs) controls the density and polarity of the accumulated charge at the critical interface between the HTL and the emission layer (EML) in organic light‐emitting diodes (OLEDs). Dipolar doping enables spontaneous orientation polarization (SOP) even in nonpolar HTL, and consequently compensates for the negative interface charge originating from the SOP of the adjacent layer. This concept is applied to a phosphorescent OLED, where bis‐4(N‐carbazolyl)phenylphosphine oxide (BCPO) is employed as a polar dopant for the HTL. The net interface charge is completely compensated at ≈29.5% of doping and further doping even facilitates the positive interface charge. The luminescence loss due to triplet‐polaron quenching is observed for both hole and electron accumulations, and it is suppressed by reducing the net interface charge density. On the other hand, the carrier balance factor linearly decreases with increasing doping ratio of BCPO. The results suggest that besides the energy level offset, SOP and permanent dipole moment of the materials should also be taken into account for realizing efficient carrier blocking interfaces. Dipolar doping is a versatile tool to tune charge accumulation, and to study its influence on device performance as well as the role of SOP in OLEDs.

A double‐click strategy for the synthesis of P and N‐containing hydrolytically stable reactive flame retardant for photocurable networks

AbstractThe use of modern chemical routes and the development of innovative material designs bring smart solutions to the problems in materials science and open up new horizons for future research. In this work, we utilized from two click reactions to prepare a P and N‐containing reactive flame retardant. The para‐fluoro groups of bis(pentafluorophenyl)phenyl phosphine oxide were converted to azides and then the obtained compound was reacted with propargyl acrylate via copper‐catalyzed azide‐alkyne cycloaddition reaction. The effect of the synthesized monomer (10%, 20%, and 30%) on the mechanical, thermal, and flame retardancy properties of an aliphatic polyurethane acrylate was investigated. The newly synthesized monomer led to a slight decrease in double bond conversion percentages, an increase in tensile strength of the photocured samples, and a decrease in the elongation at break values. The glass transition temperatures increased with the increasing amount of the flame retardant monomer as well as the limiting oxygen index (LOI) values. When the flame retardant ratio was 30% in the formulations, almost a 25% enhancement was realized in the LOI values.

Photoinitiator Selection and Concentration in Photopolymer Formulations towards Large-Format Additive Manufacturing.

Photopolymers are an attractive option for large-format additive manufacturing (LFAM), because they can be formulated from structural thermosets and cure rapidly in ambient conditions under low-energy ultraviolet light-emitting diode (UV LED) lamps. Photopolymer cure is strongly influenced by the depth penetration of UV light, which can be limited in the 2–4 mm layer thicknesses typical of LFAM. Photoinitiator (PI) systems that exhibit photobleaching have proven useful in thick-section cure applications, because they generate a photoinitiation wavefront, but this effect is time-dependent. This study investigates the light transmission and through-thickness cure behavior in (meth)acrylate photopolymer formulations with the photobleaching initiator bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (BAPO). Utilizing an optical model developed by Kenning et al., lower concentrations (0.1 wt% to 0.5 wt%) of BAPO were predicted to yield rapid onset of photoinitiation. In situ cure measurements under continuous UV LED irradiation of 380 mW/cm2 showed that a 0.1 wt% concentration of BAPO achieved peak polymerization rate within 2.5 s at a 3-mm depth. With only 1 s of irradiation at 1.7 W/cm2 intensity, the 0.1 wt% BAPO formulation also achieved the highest level of cure of the formulas tested. For an irradiation dose of 5.5 J/cm2 at a duration of 3.7 s, cured polymer specimens achieved a flexural strength of 108 MPa and a flexural modulus of 3.1 GPa. This study demonstrates the utility of optical modeling as a potential screening tool for new photopolymer formulations, primarily in identifying an upper limit to PI concentration for the desired cure depth. The results also show that photobleaching provides only a limited benefit for LFAM applications with short (1.0 s to 3.7 s) UV irradiation times and indicate that excess PI concentration can inhibit light transmission even under extended irradiation times up to 60 s.

Photo-curing of thick monomer systems with photoluminescent ZnO nanoparticles photoinitiators

The photo-curing of thick monomer systems or coatings had often been limited to the depth of a few microns to few millimeters. In order to overcome this difficult problem, the ZnO nanoparticles (NPs) were researched to improve the photo-curing depth because that ZnO had the function of the photoluminescent upon the light irradiation. The light emitted by ZnO NPs penetrated into the deeper layers to increase the photo-curing depth. The best co-photoinitiator, bis (2,4,6-trimethylbenzoyl) phenyl phosphine oxide (819), in the monomer 1, 6-hexanediol diacrylate, were determined by the UV–visible spectrophotometer and fluorescence spectrophotometer. A photo-curing depth of 16.7 mm was achieved by the combination of ZnO NPs and bis (2,4,6-trimethylbenzoyl) phenyl phosphine oxide (819) in 1, 6-hexanediol diacrylate. In addition, an experimental model was proposed, the influence factors were systematically studied, and the experimental equations related to the different factors and photo-curing depths were determined by controlling the different variables. With different variables, the maximum top layer double bond conversion of 77%, and the maximum bottom layer double bond conversion of 55%. This investigation confirmed that the photoluminescent ZnO NPs had a function of improving the photo-curing depth. Therefore, this investigation provided a new idea and method for the photo-curing of thick monomer systems and coatings.

Wide-Bandgap Perovskite Quantum Dots in Perovskite Matrix for Sky-Blue Light-Emitting Diodes.

The epitaxial growth of a perovskite matrix on quantum dots (QDs) has enabled the emergence of efficient red light-emitting diodes (LEDs) because it unites efficient charge transport with strong surface passivation. However, the synthesis of wide-band gap (Eg) QD-in-matrix heterostructures has so far remained elusive in the case of sky-blue LEDs. Here, we developed CsPbBr3 QD-in-perovskite matrix solids that enable high luminescent efficiency and spectral stability with an optical Eg of over 2.6 eV. We screened alloy candidates that modulate the perovskite Eg and allow heteroepitaxy, seeking to implement lattice-matched type-I band alignment. Specifically, we introduced a CsPb1-xSrxBr3 matrix, in which alloying with Sr2+ increased the Eg of the perovskite and minimized lattice mismatch. We then developed an approach to passivation that would overcome the hygroscopic nature of Sr2+. We found that bis(4-fluorophenyl)phenylphosphine oxide strongly coordinates with Sr2+ and provides steric hindrance to block H2O, a finding obtained by combining molecular dynamics simulations with experimental results. The resulting QD-in-matrix solids exhibit enhanced air- and photo-stability with efficient charge transport from the matrix to the QDs. LEDs made from this material exhibit an external quantum efficiency of 13.8% and a brightness exceeding 6000 cd m-2.

Characteristics of a novel photoinitiator aceanthrenequinone-initiated polymerization and cytocompatibility of its triggered polymer

A number of photoinitiators are available in chemical industry, but less of them in biomedicine or clinical therapy due to the limitation of their cytotoxicity and biocompatibility. Thus, it is urgently necessary to find non-toxic or low-toxic photoinitiators to meet clinical demands. Aceanthrenequinone (AATQ) is a novel photosensitizer with high-photoinitiating ability, but no reports contribute, to date, to its cytotoxicity and biocompatibility. Here, primary cells and various cell lines were exposed to different concentrations of AATQ with or without irradiation. AATQ had the similar photoinitiating conversion efficiency to the extensively used bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide (BAPO) and higher one than 9,10-phenanthrenequinone (PANQ) with the similar extent of polymerization in depth within a certain range, but displayed much lower cytotoxicity than BAPO under non-irradiation or irradiation. The biocompatibility of BisGMA/TEGDMA polymer prepared by AATQ was superior to that of PANQ, but inferior to that of camphorquinone (CQ) although the far lower dose of AATQ is enough to initiate polymerization of monomer than that of CQ. Hence, AATQ offers a valuable alternative in applications of industrial or biomedical areas.

Electrosynthesis of electrochromic polymers based on bis-(4-(N-carbazolyl)phenyl)-phenylphosphine oxide and 3,4-propylenedioxythiophene derivatives and studies of their applications in high contrast dual type electrochromic devices

Five phenylphosphine oxide-containing polymers (PBCPO (poly(bis-(4-(N-carbazolyl)phenyl)-phenylphosphine oxide)), P(BCPO-co-ProD-Me2), P(BCPO-co-ProD-Et2), P(BCPO-co-ProD-Bz2), and P(BCPO-co-ProD)) are electrodeposited on indium tin oxide (ITO) coated glass slide and their electrochromic performances are characterized. The optical band gap of PBCPO is 3.14 eV. P(BCPO-co-ProD-Bz2) attains a high transmittance change (ΔT = 55% at 740 nm) and shows multicolored electrochromism from light tan (0.0 V), grayish-green (0.4 V), greenish-gray (1.1 V) to deep gray (1.2 V). Electrochromic devices (ECDs) containing phenylphosphine oxide-based polycarbazoles and poly(3,4-ethylenedioxythiophene) (PEDOT) as active electrode layers are constructed. PBCPO/PEDOT ECD displays light gray, gray, and greenish-gray at 0.0, 0.8, and 1.9 V, respectively. P(BCPO-co-ProD-Bz2)/PEDOT ECD displays a high optical contrast (ΔT = 42.5% at 630 nm) and P(BCPO-co-ProD)/PEDOT ECD shows a high coloration efficiency (η = 454.1 cm2•C−1 at 630 nm). In addition, P(BCPO-co-ProD derivatives)/PEDOT ECDs have adequate optical memories and long-term redox cyclic stability.Background: Polycarbazoles can create considerably stable radical cations (polarons) and dications (bipolarons) when increasing potentials or doping chemicals. Moreover, carbazole and phenylphosphine oxide are donor (D) and acceptor (A) units in BCPO, respectively. The incorporation of phenylphosphine oxide in polycarbazoles gives rise to the improvement of charge balances and carrier mobilities. It is interesting to investigate the absorption spectra and multicolored electrochromisms of five phenylphosphine oxide-containing polycarbazoles and their corresponding ECDs upon undergoing a redox process.Methods: A series of phenylphosphine oxide-containing anodic polymers (PBCPO, P(BCPO-co-ProD-Me2), P(BCPO-co-ProD-Et2), P(BCPO-co-ProD-Bz2), and P(BCPO-co-ProD)) are electrodeposited on ITO coated glass. The absorption spectra, color variations, response time, and long-term electrochemical stability of PBCPO/PEDOT, P(BCPO-co-ProD-Me2)/PEDOT, P(BCPO-co-ProD-Et2)/PEDOT, P(BCPO-co-ProD-Bz2)/PEDOT, and P(BCPO-co-ProD)/PEDOT ECDs are investigated comprehensively.Significant findings: The as-prepared phenylphosphine oxide-containing polycarbazoles exhibit multicolored electrochromism and high transmittance change (ΔT = 55% at 740 nm), which provide new structural insights to develop new generation electrochromic electrodes.

Enantioseparation of P-Stereogenic Secondary Phosphine Oxides and Their Stereospecific Transformation to Various Tertiary Phosphine Oxides and a Thiophosphinate.

Secondary phosphine oxides incorporating various aryl and alkyl groups were synthesized in racemic form, and these products formed the library reported in this study. TADDOL derivatives were used to obtain the optical resolution of these P-stereogenic secondary phosphine oxides. The developed resolution method showed a good scope under the optimized reaction conditions, as 9 out of 14 derivatives could be prepared with an enantiomeric excess (ee) ≥ 79% and 5 of these derivatives were practically enantiopure >P(O)H compounds (ee ≥ 98%). The scalability of this resolution method was also demonstrated. Noncovalent interactions responsible for the formation of diasteromeric complexes were elucidated by single-crystal XRD measurements. (S)-(2-Methylphenyl)phenylphosphine oxide was transformed to a variety of P-stereogenic tertiary phosphine oxides and a thiophosphinate in stereospecific Michaelis–Becker, Hirao, or Pudovik reactions.

Electrocatalytic C–H phosphorylation through nickel(III/IV/II) catalysis

<h2>Summary</h2> C–H phosphorylation was achieved by Earth-abundant nickel catalysts with waste-free electricity as the redox surrogate. The robust nickela-electrooxidative C–H activation of arenes, heteroarenes, and olefins with diverse phosphonating reagents successfully delivered arylphosphonates, phenylphosphine oxides, and diazaphospholidine oxides of relevance to bioactive compounds and materials. The guanidine-assisted electrooxidative C–P formation avoided chemical oxidants with molecular hydrogen as the sole byproduct. Catalytically relevant nickel(II) and nickel(III) intermediates were isolated and fully characterized by X-ray diffraction analysis. Catalytically relevant nickel complexes were observed by <i>in operando</i> high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) monitoring. Cyclic voltammetry analysis and density functional theory (DFT) calculations provided strong evidence for a nickel(III/IV/II) manifold.

Investigation of Structural Changes of Cu(I) and Ag(I) Complexes Utilizing a Flexible, Yet Sterically Demanding Multidentate Phosphine Oxide Ligand.

The syntheses of a sterically demanding, multidentate bis(quinaldinyl)phenylphosphine oxide ligand and some Cu(I) and Ag(I) complexes thereof are described. By introducing a methylene group between the quinoline unit and phosphorus, the phosphine oxide ligand gains additional flexibility. This specific ligand design induces not only a versatile coordination chemistry but also a rarely observed and investigated behavior in solution. The flexibility of the birdlike ligand offers the unexpected opportunity of open-wing and closed-wing coordination to the metal. In fact, the determined crystal structures of these complexes show both orientations. Investigations of the ligand in solution show a strong dependency of the chemical shift of the CH2 protons on the solvent used. Variable-temperature, multinuclear NMR spectroscopy was carried out, and an interesting dynamic behavior of the complexes is observed. Due to the introduced flexibility, the quinaldinyl substituents change their arrangements from open-wing to closed-wing upon cooling, while still staying coordinated to the metal. This change in conformation is completely reversible when warming up the sample. Based on 2D NMR spectra measured at -80 °C, an assignment of the signals corresponding to the different arrangements was possible. Additionally, the copper(I) complex shows reversible redox activity in solution. The combination of structural flexibility of a multidentate ligand and the positive redox properties of the resulting complexes comprises key factors for a possible application of such compounds in transition-metal catalysis. Via a reorganization of the ligand, occurring transition states could be stabilized, and selectivity might be enhanced.

Atomic Oxygen-Resistant Epoxy-amines Containing Phenylphosphine Oxide as Low Earth Orbit Stable Polymers

Atomic oxygen (AO) attacks carbon-fiber reinforcing polymers on the surfaces of spacecraft in low Earth orbit and threatens safe spacecraft operation and service life. Incorporating phenylphosphine...

Synthesis of novel aromatic polyamides containing cardo groups and triphenylphosphine oxide structures by a heterogeneous palladium-catalyzed carbonylation and condensation reaction

New aromatic polyamides containing cardo groups and triphenylphosphine oxide structures were synthesized by a heterogeneous palladium-catalyzed carbonylation and condensation of bis(4-(3-iodophenoxy)phenyl)phenylphosphine oxide (BIPPO), aromatic diamines bearing cardo groups, and carbon monoxide. Polycondensations were carried out in N,N-dimethylacetamide under 1 atm of CO at 120 °C in the presence of a magnetically recyclable heterogeneous palladium catalyst and 1,8-diaza-bicyclo[5,4,0]-7-undecene (DBU) and afforded novel aromatic polyamides with inherent viscosities between 0.72 and 0.76 dL/g. All the polyamides were quite soluble in dipolar aprotic solvents and pyridine and could be converted into transparent, flexible, and tough polyamide films by casting from DMAc solutions. These polymers exhibited high thermal and thermooxidative stability with the glass transition temperatures of 237 °C–256 °C, the temperatures at 5% weight loss of 448 °C–465 °C in air. All the phosphorus-containing polyamides self-extinguished as soon as the flame was removed, and the limited oxygen indices (LOIs) of these polymers were in the range of 39%–44%. The polymer films also showed good mechanical properties and high optical transparency.

A CTV Analogue: Arene-Persubstituted Cyclotrixylohydroquinoylene and Its Derivatives.

A crown-shaped cyclotriveratrylene (CTV) analogue with persubstituted arene units-namely, cyclotrixylohydroquinoylene (CTX)-was synthesized from tetrasubstituted o-xylohydroquinone. Importantly, a series of CTX derivatives were prepared by introducing second bridged methylene, phenylphosphine oxide, and dimethylsilyl at the middle rim, referred to as CTX[CH2], CTX[P(O)Ph], and CTX[SiMe2], respectively, with the completely locked crown conformation, leading to the formation of unique C3-symmetric Chinese censer-shaped pocket structures. In addition, the water-soluble CTX[CH2] derivative (WCTX[CH2]) was synthesized from CTX[CH2] by simple oxidation reaction with the modification at the upper rim, and its host-guest interaction with methyl viologen in water was investigated.

Oxaphosphacyclophanes Constructed from a Bis(triphenylphosphine oxide) Moiety Linked by Dioxyalkyl Chains: Synthesis and Crystal Structures.

Oxaphosphacyclophanes, a bis(triphenylphosphine oxide) moiety linked by dioxypropane, dioxybutane, dioxypentane, and dioxyhexane, were synthesized from the reaction of bis(4-hydroxyphenyl)phenylphosphine oxide and dibromoalkanes. Single-crystal X-ray diffraction analysis and exploring intermolecular interactions by using the Hirshfeld surface revealed that the butylene-linked oxaphosphacyclophane (2) had a one-dimensional (1D) supramolecular structure via CH/π interactions between the terminal phenyl group of 2 and a phenylene group of the cavities. In the packing diagram of pentylene-linked oxaphosphacyclophane (3) with antiform, one macrocycle recognized two terminal phenyl groups to form a 1D supramolecular chain via π/π interactions. The syn-form of 3 was obtained by the recrystallization from toluene and CHCl3. In this crystal, a toluene molecule avoid construction of a 1D chain. The antiform of hexylene-linked oxaphosphacyclophane 4 was obtained by the recrystallization from cyclohexane and CHCl3. Cyclohexane was captured in the cavity via CH/π interactions. Two molecules of 4 with the syn-form recognized each other to construct a dimeric structure via CH/π interactions.