Diphenylphosphine Oxide Research Articles

In vitro cytotoxicity evaluation of organotin(IV) complexes derived from bisphosphoramide ligand: DNA binding and molecular docking studies

Considering the valuable position of organotins and the biotic role of phosphorus compounds in biological processes, in this research work, we investigated and introduced a new class of anticancer candidates based on organotin(IV) complexes derived from bisphosphoramide ligands. Four selected complexes were prepared from the reaction of SnMe2Cl2 (C1), SnBu3Cl (C2), SnPh2Cl2 (C3), and SnPh3Cl (C4) metal salts with piperazine-1,4-diylbis(diphenylphosphine oxide) ligand (LP). The newly synthesized complexes were characterized using spectroscopic techniques. Single crystal of C1 structure was determined by X-ray crystallography. Binding potentials of compounds to DNA were also explored using electron absorption titration and competitive fluorescence quenching techniques, which indicated that complexes and CT-DNA strongly interacted. Cytotoxicity assay of compounds against triple-negative human breast cancer (MDA-MB-231) cells proved that three complexes C2, C3, and C4 had a very considerable impact on the reduced viability of cancer cells and among them, C4 revealed the maximum anticancer activity (IC50 = 0.35 ± 1.18 µg/mL, 0.28 µM) in comparison to reference cisplatin drug (IC50 = 19 µM). Furthermore, the analysis and comparison of the orientations and reactive sites of the compounds using molecular docking simulation, pharmacophore, and NCI studies further confirmed the significant effects of the type and number of aryl and alkyl substituents on the biological activities.

Effect of novel furan‐based ester reactive diluent on structure and properties of UV‐crosslinked acrylated rapeseed oil

AbstractUnsaturated furan‐based ester (UES) was prepared by green electrosynthesis using a single‐cell setup and inexpensive graphite electrodes. The UES was validated as a reactive diluent for a bio‐based acrylated rapeseed oil (ARO). UV‐light photopolymerization of the bio‐based resin was initiated using a diphenyl (2,4,6‐trimethylbenzoyl)phosphine oxide (TPO) radical photoinitiator. The addition of 20 wt% UES to ARO dropped the resin viscosity by 1.6‐fold. Incorporating 5 wt% UES into the ARO resin increased crosslinking density νe from 1.07 to 1.65 mol/m3. Fourier‐transform infrared spectroscopy (FT‐IR) spectra revealed that ARO has been grafted with UES. The UES functional moieties promote the formation of soft mobile dangling chain end segments in the developed macromolecular network. UV‐cured thermoset polymer reveals distinct morphologies in SEM micrographs, indicating notable structural changes with the addition of UES. A total of 5 wt% UES increased tensile strength from 0.49 to 0.55 MPa and storage modulus from 7.9 to 12.0 MPa at room temperature (22 ± 1 °C). The biodegradability in composting conditions was investigated, and up to 28% of the initial mass was lost after 60 days. UES was shown as to be efficient reactive diluent that can successfully replace fossil‐based acrylate monomers in vegetable oil‐based thermoset polymer synthesis.

One-pot synthesis of (2,4,6-Trimethylbenzoyl)diphenylphosphine oxide from triphenylphosphine oxide

A simple one-pot preparation of (2,4,6-Trimethylbenzoyl)diphenylphosphine oxide (TPO) by employing the low-cost triphenylphosphine oxide (Ph3PO) as the starting material was described. Reaction with trimethylsilyl chloride (TMSCl) that transforms the intermediate sodium diphenylphosphonite (Ph2PONa) into (trimethylsilyl)oxy)diphenylphosphine (Ph2POTMS) is the key for the high yield of TPO. The reactions of Ph2PONa with other silyl chlorides are discussed.

Synthesis and properties of acyldiphenylphosphine oxides photoinitiators carrying ferrocene group for free radical photopolymerization

Thick film curing has become a research hotspot in photocuring systems, among which designing and synthesizing visible light initiators is particularly important. Herein, two new visible light initiators of (diphenylphosphoryl)(ferrocene-1-yl)methanone (FEPO) and ferrocene-1,1′-diylbis((diphenylphosphoryl)methanone) (FSPO) were designed and synthesized from diphenylphosphine oxide reacting with ferrocenecarboxaldehyde and 1,1′-ferrocenedicarboxaldehyde, respectively. FEPO and FSPO possess good solubility in different solvents and acrylic monomers. The UV-Vis spectrums of FEPO and FSPO showed that they exhibit a wide absorption range of 300–670 nm, and the maximum absorption wavelengths are about 494 nm and 505 nm, with a molar extinction coefficient of around 1226 M⁻¹cm⁻¹ and 299 M⁻¹cm⁻¹, suggesting that they are likely to be visible light photoinitiator (PI). The addition of N-phenylglycine (NPG) significantly improved the curing efficiency of FEPO and FSPO, the degree of double bond conversion (DC) of FSPO increased from 27 % to 48 % under the irradiation of LED@480 nm, while, under the irradiation of LED@405 nm, the DC of FEPO/NPG is about 52 %. Moreover, the curing depth of FEPO/NPG/trimethylolpropane triacrylate (TMPTA) (1.75 cm) was about 1.8 times that of diphenyl(2,4,6-trimethylbenzoyl) phosphine oxide (TPO)/TMPTA (0.98 cm) after irradiating for 5 min. In addition, FEPO can be used in laser cladding deposition (LCD) 3D printers with light-emitting diode (LED)@405 nm. Using steady-state photolysis and electron spin resonance spin-trapping studies, the photocuring mechanism was examined. Additionally, photoinitiators (PIs) also exhibit superior biocompatibility performance demonstrated by cytotoxicity assays, suggesting they might be utilized in 3D printing in biological materials and coatings for food packaging.

Towards safe phosphine oxides photoinitiators with good cytocompatibility for 3D printing of thermoplastics

Abstract3D printing is the technology of choice for the rapid production of objects with complex morphologies and controlled physical and chemical properties. 3D printing by photopolymerization is of great interest because of its ability to access very small scales and its high resolution. In the case of recent 3D printers, the preferred wavelength for light irradiation is 405 nm since it is a safe and energy‐economical irradiation. For 3D printing to be effective, it is therefore necessary to develop easily accessible, stable and highly efficient photoinitiating systems at the 405 nm wavelength. Beside, with the increasing use of photoinitiators, it is essential to develop structures with low cytotoxicity. Hence, the development of new photoinitiators is currently of major interest. To this end, the photochemical properties (triplet energy, bond dissociation energy, cleavage reaction enthalpy, and absorption properties) of several molecules have been calculated by molecular modeling and the most promising compounds have been synthesized. In this paper, four phosphine oxides photoinitiators (ADPO‐1, CPO‐2, CPO‐3, and FPO‐1) are synthesized and characterized. Subsequently, their absorption properties are measured and their efficiencies in photopolymerization under LED irradiation at 405 nm are evaluated. It is important to note that these structures have never been reported in 3D printing. Markedly, among the obtained photoinitiators, two of them show better efficiency than the commercially available and widely used phenylbis(2,4,6‐trimethylbenzoyl)phosphine oxide (BAPO) in photopolymerization (i.e., (Rp/[M0]) x100 values are 6.94, 12.95, and 4.93 s−1 for CPO‐2, ADPO‐1, and BAPO; with [M0] the initial acrylate function concentration). Furthermore, one of the synthesized photoinitiators is successfully used in 3D printing of thermoplastics for potential recycling ability. Finally, one of the obtained structures shows a lower cytotoxicity than the benchmark structure diphenyl(2,4,6‐trimethylbenzoyl)phosphine oxide (TPO).

Cerium(IV) Nitrate Complexes With Bidentate Phosphine Oxides

AbstractThe reactions between ceric ammonium nitrate, (NH4)2Ce(NO3)6, (CAN) and the bidentate phosphine oxides, 4,5‐bis(diphenylphosphine oxide)‐9,9‐dimethylxanthene (L1), oxydi‐2,1‐phenylene bis(diphenylphosphine dioxide) (L2), 1,2‐bis(diphenylphosphino)ethane dioxide (L3) and 1,4‐bis(diphenylphosphino)butane dioxide, L4 have been investigated. The crystal structures of the molecular Ce(NO3)4L1 (1), and ionic [Ce(NO3)3L32][NO3]⋅CHCl3 (3), [Ce(NO3)3L32][NO3] (4) and the polymeric [Ce(NO3)3L41.5] [NO3] (5) and the cerium(III) complex [Ce(NO3)2L12][NO3] (2) are reported. The thermal stability of the complexes has been examined by thermogravimetry with the gaseous decomposition products analysed by infrared spectroscopy. Evolution of CO2 is found for both Ce(III) and Ce(IV) complexes with the later also forming NO2. The formation of the complexes in solution has been studied by 31P NMR spectroscopy and further complexes [Ce(NO3)3L12]+[NO3]− and [Ce(NO3)2L13]2+2[NO3]− identified in CD3CN solution. The complex (1) exists as a single molecular species in solution and is stable in dichloromethane whilst (3) decomposes on standing in both CD2Cl2 and CD3CN to Ce(III) containing species. Complexes of L2 have been identified by solution 31P NMR spectroscopy and these decompose in solution to give Ce(NO3)3L22. This study represents the first structural characterisations of Ce(IV) complexes with bidentate phosphine oxides.

Influence of metal on coordination geometry and solution dynamics in complexes of cis-ethylenebis(diphenylphosphine oxide) and Ln(OTf)3 (Ln = La, Sm, Lu) X-ray crystal structures and NMR titration studies

This paper describes the synthesis and characterization of complexes containing the relatively rigid bisphosphine oxide ligand cis-ethylenebis(diphenylphosphine oxide) with three lanthanide (Ln) triflate salts (Ln = La3+, Sm3+, Lu3+). The complexes were characterized in the solid state by IR and X-Ray crystallography and show bidentate binding of the ligand to each metal center. The complexes were also studied at various Ln-ligand stoichiometries in solutions of CDCl3 using 1H and 31P NMR. These studies revealed that for the complexes where Ln = La3+ and Sm3+ ligand exchange is fast on the 1H and 31P NMR time scales when there are less than four equivalents of ligand in solution but slows when more than four equivalents are present. For the solution studies of complexes with Lu3+, ligand exchange is fast on the 1H NMR but slow on the 31P NMR time scale for all Lu-ligand stoichiometries.

Nontarget Identification of Novel Organophosphorus Flame Retardants and Plasticizers in Rainfall Runoffs and Agricultural Soils around a Plastic Recycling Industrial Park.

Plastic recycling and reprocessing activities may release organophosphate ester (OPE) flame retardants and plasticizers into the surrounding environment. However, the relevant contamination profiles and impacts remain not well studied. This study investigated the occurrence of 28 OPEs and their metabolites (mOPEs) in rainfall runoffs and agricultural soils around one of the largest plastic recycling industrial parks in North China and identified novel organophosphorus compounds (NOPs) using high-resolution mass spectrometry-based nontarget analysis. Twenty and twenty-seven OPEs were detected in runoff water and soil samples, with total concentrations of 86.0-2491 ng/L and 2.53-199 ng/g dw, respectively. Thirteen NOPs were identified, of which eight were reported in the environment for the first time, including a chlorine-containing OPE, an organophosphorus heterocycle, a phosphite, three novel OPE metabolites, and two oligomers. Triphenylphosphine oxide and diphenylphosphinic acid occurred ubiquitously in runoffs and soils, with concentrations up to 390 ng/L and 40.2 ng/g dw, respectively. The downwind areas of the industrial park showed elevated levels of OPEs and NOPs. The contribution of hydroxylated mOPEs was higher in soils than in runoffs. These findings suggest that plastic recycling and reprocessing activities are significant sources of OPEs and NOPs and that biotransformation may further increase the ecological and human exposure risk.

Structural and Magnetic Analysis of a Family of Structurally Related Iron(III)-Oxo Clusters of Metal Nuclearity Fe8, Fe12Ca4, and Fe12La4

The synthesis, crystal structure, and magnetic characterization are reported for three new structurally related iron(III) compounds (NHEt3)[Fe8O5(OH)5(O2PPh2)10] (1), [Fe12 Ca4O10(O2CPh)10(hmp)4] (2), and [Fe12La4O10(OH)4(tbb)24] (3), where hmpH is 2-(hydroxymethyl)pyridine and tbbH is 4-tBu-benzoic acid. 1 was obtained from the reaction of Fe(NO3)3·9H2O, diphenylphosphinic acid (Ph2PO2H), and NEt3 in a 1:4:16 molar ratio in MeCN at 50 °C; 2 was obtained from the reaction of [Fe3O(O2CPh)6(H2O)3](NO3), Ca(NO3)2, and NEt3 in a 1:1:4:2 ratio at 130 °C; and 3 was obtained from the reaction of Fe(NO3)3·9H2O, La(NO3)3·6H2O, 4-tBu-benzoic acid, and NEt3 in a 1:1:4:4 ratio in PhCN at 140 °C. The core of 1 consists of two {Fe4(µ3-O)2}8+ butterfly units stacked on top of each other and bridged by O2− and HO− ions. The cores of 2 and 3 also contain two stacked butterfly units, plus four additional Fe atoms, two at each end, and four M atoms (M = Ca2+ (2); La3+ (3)) on the sides. Variable-temperature (T) and solid-state dc and ac magnetization (M) data collected in the 1.8–300 K range revealed that 1 has an S = 0 ground state, 2 has a χMT value at low T consistent with the central Fe8 in a local S = 0 ground state and the two Fe3+ ions in each end-pair to be non-interacting, whereas 3 has a χMT value at low T consistent with these end-pairs each being ferromagnetically coupled with S = 5 ground states, plus intermolecular ferromagnetic interactions. These conclusions were reached from complementing the experimental studies with the calculation of the various Fe2 pairwise Jij exchange couplings by DFT computations and by using a magnetostructural correlation (MSC) for polynuclear Fe3+/O complexes, as well as a structural analysis of the intermolecular contacts in the crystal packing of 3.

Synthesis and properties of acyldiphenylphosphine oxides photoinitiators carrying triphenylamine or pyrene group for free radical photopolymerization

AbstractTwo new photoinitiators of acyldiphenylphosphine oxides carrying triphenylamine (NHPO) or pyrene group (BHPO) were designed and synthesized with diphenylphosphine oxide reacting with 4‐(diphenylamino) benzaldehyde or 1‐pyrenecarboxaldehyde. The solubility of NHPO is about 13.7 wt% in TMPTA, which is higher than that of (2,4,6‐trimethylbenzoyl) diphenylphosphine oxide (TPO) (about 12.5 wt%). The UV–Vis spectrum of NHPO and BHPO revealed that their maximum absorption wavelengths have redshifted to 397 and 419 nm, respectively, with a molar extinction coefficient of around 19,057 and 24,257 M−1 cm−1, suggesting that they are likely to be effective photoinitiators when exposed to light from LEDs. According to real‐time Fourier transform infrared spectroscopies, the degree of double bond conversion of NHPO reached 65%, which was higher than that of TPO (about 45%), showing that NHPO had substantially better photoinitiated properties than TPO. Using steady‐state photolysis and electron spin resonance spin‐trapping studies, the photocuring mechanism was examined, and it was discovered that the NHPO and BHPO had produced two free radicals. Additionally, NHPO exhibited superior biocompatibility performance as demonstrated by cytotoxicity assays and had a low migration rate of only 0.23%, as determined by migration. As a result, NHPO might be utilized in coatings for food packaging.

Synthesis and Characterisation of Hydrogels Based on Poly (N-Vinylcaprolactam) with Diethylene Glycol Diacrylate.

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.

The atomic oxygen resistant study of a transparent polyimide film containing phosphorus and fluorine

As ideal packaging materials for solar cells of low-Earth orbit (LEO) spacecraft, polyimide (PI) films have to withstand various harsh space environment. Here, we investigate the atomic oxygen (AO)-resistant property of a transparent PI film with side diphenylphosphine oxide and trifluoromethyl. After exposed under AO (1.3 × 1020 atoms·cm−2), most excellent properties of the PI film can be maintained except for partial loss of transmittance. Its erosion yield is 0.56 × 10−24 cm3·atom−1, only 18.7% as that of Kapton film at the same condition. To understand the damage mechanism, the surface and bulk performances of the AO exposed PI film were systematically investigated and compared with those of the prinstine PI film. The results indicate that the relative concentration of phosphorus and oxygen near to the AO exposed surface of the PI film increases, which means the formation of a phosphate passivation layer. The thickness of phosphate passivation layer is about 200 nm with the content of PO3− decreasing in vertical direction of itself, which can reduce the further erosion of the PI film by AO. Such PI films containing P and F are much more AO resistant and expected a candidate as packaging material for LEO spacecraft.

Enantioselective Synthesis of 1,3-Benzothiazine Derivatives: An Organocatalytic Chemoselective Approach.

Herein, a highly chemoselective 1,2-addition of thiols with 2-isothiocyanatochalcones followed by an enantioselective intramolecular thia-Michael addition cascade has been established to construct enantioenriched [1,3]-benzothiazine derivatives for the first time. The cinchona-derived squaramide catalyst provides good to excellent yield and enantioselectivity of the products with broad substrate adaptability. Furthermore, this strategy has been extended to the diphenylphosphine oxide nucleophile to access enantioenriched organophosphorus-substituted [1,3]-benzothazines. A scale-up reaction and synthetic transformation have demonstrated the viability of this protocol.

A Phosphine Oxide-Functionalized Cyclam as a Specific Copper(II) Chelator

Although cyclam-based ligands are among the strongest copper(II) chelators available, they also usually present good affinity for other divalent cations [Zn(II), Ni(II), and Co(II)], with no copper(II)-specific cyclam ligands having been described so far. As such a property is highly desirable in a wide range of applications, we present herein two novel phosphine oxide-appended cyclam ligands that could be efficiently synthesized through Kabachnik-Fields type reactions on protected cyclam precursors. Their copper(II) coordination properties were closely studied by different physicochemical techniques [electron paramagnetic resonance (EPR) and ultraviolet-visible (UV-vis) spectroscopies, X-ray diffraction, and potentiometry]. The mono(diphenylphosphine oxide)-functionalized ligand demonstrated a copper(II)-specific behavior, unprecedented within the cyclam family of ligands. This was evidenced by UV-vis complexation and competition studies with the parent divalent cations. Density functional theory calculations also confirmed that the particular ligand geometry in the complexes strongly favors copper(II) coordination over that of competing divalent cations, rationalizing the specificity observed experimentally.

Color‐Stable Two‐Dimensional Tin‐Based Perovskite Light‐Emitting Diodes: Passivation Effects of Diphenylphosphine Oxide Derivatives

AbstractThe performance of tin (Sn)‐based perovskite light‐emitting diodes (PeLEDs) lags behind their lead analogs due to the challenges of Sn2+ oxidation, defect passivation, and fast crystallization. Herein, the passivation effects of diphenylphosphine oxide (DPPO) derivatives on the fabrication of PEA2SnI4 films are investigated. The DPPO derivatives with hydroxyl group, or including substituent group with the potential to form hydroxyl group, are unfavorable passivators due to their positive effects in accelerating Sn2+ oxidation. In comparison, amino‐functionalized DPPO molecule is an effective additive to enhance the photoluminescence of PEA2SnI4 films due to the effective defect passivation as well as crystallinity improvement. Based on the optimized films, color‐stable pure‐red PeLEDs are demonstrated with a full width at half maximum of 23 nm at 630 nm, a maximum luminance of 451 cd m−2, a maximum external quantum efficiency of 3.51%, and a half‐lifetime of 13.7 min at 102 cd m−2. This work opens new prospects on the selection of effective molecular additives for Sn‐based perovskites.

Effect of substitution on light-curable properties in diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide: DFT and TD-DFT calculations

Acylphosphine oxide-based photoinitiators have been used in digital light processing (DLP) 3D printing slurry to prepare ceramic materials. However, the limitation is how to improve the absorption efficiency of photoinitiator in UV–Vis light and its initiation efficiency. In this study, through the DMol3 module of Materials Studio, the hydrogen atom is substituted by different electron-donating substituents (-NH2, -OCH3, -OH), substitution positions (ortho, meta, para) and tri-substitutions positions (2,4,6 and 3,4,5) were systematically studied respectively, including the change from the ground state to the first excited state, energy gap, ultraviolet-visible spectrum, the excitation energy, absorption wavelength, and oscillator strength. These results show that the order of electron-donating ability of these four groups is as follows: -NH2 > -OCH3 > -OH> -H. When the initiation wavelength λ≤ 425 nm, enhancing the electron-donating ability of the substituent and substitute para-substitution position can improve the oscillator strength and cause a blue-shift of the absorption peak. 4-TPO-NH2 which has the strongest electron-donating ability group substituted in para position shows the highest oscillator strength (21.5%) and blue shift (22 nm) compared with unsubstituted TPO. When the initiation wavelength λ≥ 425 nm, enhancing the electron-donating ability of the substituent, substitute para-substitution or ortho-substitution position, and tri-substituents of 2,4,6 positions, is the most beneficial to improve the oscillator strength and the red-shift of the absorption peak. Compared to unsubstituted TPO, 2,4,6-TPO-NH2 has 9.00 times increase in oscillator strength with 122 nm red-shift, and 2-TPO-NH2 has 134 nm red-shift with 2.53 times increase in oscillator strength. Furthermore, these studies can improve the development of acylphosphine oxide-based photoinitiators, and will also help to expand the application of DLP 3D printing in ceramic fields.

Proton-transfer salts of diphenylphosphinic acid with substituted 2-aminopyridine: crystal structure, spectroscopic and DFT studies.

Three proton-transfer salts of diphenylphosphinic acid (DPPA) with 2-amino-5-(X)-pyridine (AMPY, X= Cl, CN or CH3), namely, 2-amino-5-chloropyridinium diphenylphosphinate, C5H6ClN2+·C12H10O2P- (1, X= Cl), 2-amino-5-cyanopyridinium diphenylphosphinate, C6H6N3+·C12H10O2P- (2, X= CN), and 2-amino-5-methylpyridinium diphenylphosphinate, C6H9N2+·C12H10O2P- (3, X= CH3), have been synthesized and characterized by FT-IR and 1H NMR spectroscopy, and X-ray crystallography. The crystal structures of compounds 1-3 were determined in the space group P\overline{1} for 1 and 2, and C2/c for 3. All three compounds contain N-H...O hydrogen-bonding interactions due to proton transfer from the O=P-OH group of DPPA as donor to the pyridine N atom of AMPY as acceptor. The proton transfer of compounds 1-3 was also verified by 1H NMR and FT-IR spectroscopy. The stoichiometry of all three proton-transfer salts was determined to be 1:1 and the Benesi-Hildebrand equation was applied to determine the formation constant (KCT) and the molar extinction coefficient (ϵCT) in each case. Theoretical density functional theory (DFT) calculations were performed to investigate the optimized geometries, the molecular electrostatic potentials (MEP) and the highest occupied molecular orbitals (HOMO) and lowest unoccupied molecular orbitals (LUMO) of all three proton-transfer salts. The results showed good agreement between the experimental data and the DFT computational analysis.

Preparation and characterization of photocurable fluorinated polyether‐based reactive inks

AbstractPhotocurable polymer provides fast curable properties via ultraviolet (UV) light for 3D‐printed propellants. This work outlines the preparation and characterization of photocurable fluorinated polyether‐based reactive inks. Acrylate‐terminated poly‐2‐((2,2,3,3,3‐pentafluoropropoxy)‐methyl) ethylene oxide (P5F‐AA) was synthesized as photocurable binder through the esterification of acrylic acid, and the terminal hydroxyl group of poly‐2‐((2,2,3,3,3‐pentafluoropropoxy)‐methyl) ethylene oxide (P5F), which was synthesized through cationic ring‐opening polymerization of 2‐((2,2,3,3,3‐pentafluoropropoxy)methyl) oxy‐ethane (PFEE) by using butane diol as initiator. In comparison with P5F, P5F‐AA had a lower glass transition temperature (Tg) of −63.3°C. A new type of photocurable resin, which may be used for additive manufacturing of energetic materials, was prepared via UV radiation in an LED UV curing tank by using P5F‐AA as prepolymer, diphenyl (2,4,6‐trimethyl benzoyl) phosphine oxide (TPO) as photo‐initiator, and tri‐fluoroethyl acrylate (3F‐AA) and 1,6‐hexanediol diacrylate (HDDA) as mono‐ and multifunctional diluents, respectively. When the mass ratio of P5F‐AA/3F‐AA/HDDA binder matrix was 1:1:0.5, the sample exhibited maximal mechanical strength of 6.56 MPa with elongation at break of 13.38%, which was due to the introduction of HDDA effectively increasing the “entanglement” between molecular chains. Thermogravimetric analysis (TGA‐DTG) was utilized to evaluate the ability to decompose thermally of the binder matrix, and the results showed the initial degradation temperature started at nearly 181°C and two consecutive stages in thermal decomposition. Overall, the obtained results from the different techniques suggested that P5F‐AA/3F‐AA/HDDA binder matrix may be a photocurable reactive ink for 3D‐printed propellants, which would provide a certain reference value and guiding importance for design of reactive inks.

Low-Viscosity Polydimethylsiloxane Resin for Facile 3D Printing of Elastomeric Microfluidics.

Microfluidics is a rapidly advancing technology with expansive applications but has been restricted by slow, laborious fabrication techniques for polydimethylsiloxane (PDMS)-based devices. Currently, 3D printing promises to address this challenge with high-resolution commercial systems but is limited by a lack of material advances in generating high-fidelity parts with micron-scale features. To overcome this limitation, a low-viscosity, photopolymerizable PDMS resin was formulated with a methacrylate-PDMS copolymer, methacrylate-PDMS telechelic polymer, photoabsorber, Sudan I, photosensitizer, 2-isopropylthioxanthone, and a photoinitiator, 2,4,6-trimethyl benzoyl diphenylphosphine oxide. The performance of this resin was validated on a digital light processing (DLP) 3D printer, an Asiga MAX X27 UV. Resin resolution, part fidelity, mechanical properties, gas permeability, optical transparency, and biocompatibility were investigated. This resin produced resolved, unobstructed channels as small as 38.4 (±5.0) µm tall and membranes as thin as 30.9 (±0.5) µm. The printed material had an elongation at break of 58.6% ± 18.8%, Young's modulus of 0.30 ± 0.04 MPa, and was highly permeable to O2 (596 Barrers) and CO2 (3071 Barrers). Following the ethanol extraction of the unreacted components, this material demonstrated optical clarity and transparency (>80% transmission) and viability as a substrate for in vitro tissue culture. This paper presents a high-resolution, PDMS 3D-printing resin for the facile fabrication of microfluidic and biomedical devices.

Water-soluble phosphate-pillar[5]arene (WPP5)-based artificial light-harvesting system for photocatalytic cross-coupling dehydrogenation

A novel water-soluble phosphate-pillar[5]arene (WPP5)-based artificial light-harvesting system (LHS) was successfully fabricated through the supramolecular assembly of phenyl-pyridyl-acrylonitrile derivative (PBT), WPP5, and organic pigment Eosin Y (ESY). Initially, after host–guest interaction, WPP5 could bind well with PBT and form WPP5 ⊃ PBT complexes in water, which further assembled into WPP5 ⊃ PBT nanoparticles. WPP5 ⊃ PBT nanoparticles performed an outstanding aggregation-induced emission (AIE) capability because of the J-aggregates of PBT in WPP5 ⊃ PBT nanoparticles, which were appropriate as fluorescence resonance energy transfer (FRET) donors for artificial light-harvesting. Moreover, due to the emission region of WPP5 ⊃ PBT overlapped well with the UV–Vis absorption of ESY, the energy of WPP5 ⊃ PBT (donor) could be significantly transferred to ESY (acceptor) via FRET process in WPP5 ⊃ PBT-ESY nanoparticles. Notably, the antenna effect (AEWPP5⊃PBT-ESY) of WPP5 ⊃ PBT-ESY LHS was determined to be 30.3, which was much higher than that of recent artificial LHSs for photocatalytic cross-coupling dehydrogenation (CCD) reactions, suggesting a potential application in photocatalytic reaction. Furthermore, through the energy transfer from PBT to ESY, the absolute fluorescence quantum yields performed a remarkable increase from 14.4% (for WPP5 ⊃ PBT) to 35.7% (for WPP5 ⊃ PBT-ESY), further confirming their FRET processes in WPP5 ⊃ PBT-ESY LHS. Subsequently, in order to output the harvested energy for catalytic reactions, WPP5 ⊃ PBT-ESY LHSs were used as photosensitizers to catalyze the CCD reaction of benzothiazole and diphenylphosphine oxide. Compared to free ESY group (21%), a significant cross-coupling yield of 75% in WPP5 ⊃ PBT-ESY LHS was observed, because more UV region energy of PBT was transferred to ESY for CCD reaction, which suggested more potential in improving the catalytic activity of organic pigment photosensitizers in aqueous systems.