2-methoxyethanol Research Articles

Sodium phosphate solid base catalysts for production of novel biodiesel by transesterification reaction.

The efficient sodium phosphate (Na3PO4) solid base catalysts were prepared and applied in the production of novel biodiesel: ethylene glycol monomethyl ether monolaurate (EGMEML) by transesterification. The calcined sodium phosphate catalysts (NaP-T) were characterized using thermogravimetry analysis (TG-DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) and so on. The effects of calcination temperature of Na3PO4 and main reaction parameters such as molar ratio of ethylene glycol monomethyl ether (EGME) to methyl laurate (ML), dosage of catalyst, reaction time and temperature on the yield of EGMEML were examined. The results showed that the maximum yield of EGMEML could reach 90% under 120 °C within 4 h and 5 wt% of Na3PO4 calcined at 400°, and the catalysts displayed good stability and recovery. In addition, the kinetics of transesterification reaction was explored and the results showed that the transesterification reaction followed 1st order kinetics when a large excess of EGME was used, the activation energy (Ea) was found to be 40.2 kJ mol-1.

Time-domain Tollens reaction: synthesising silver nanoparticles with the formaldehyde clock.

The addition of silver(i) ions to the methylene glycol-sulphite (MGS) clock reaction results in the sudden formation of metallic silver nanoparticles. Stable suspensions are obtained in the presence of poly(vinylpyrrolidone). The time delay before the appearance of the particles, as well as their size, decreases with the initial methylene glycol concentration while their monodispersity increases.

Carbon nanofiber-reinforced shape memory polyurethanes based on HTPB/PTMG blend as anticorrosive coatings

ABSTRACT Aiming at an easy-processing shape memory polymer, we report different thermo-responsive shape memory polyurethane (SMPU) nanocomposites derived from Hydroxyl Terminated Poly-Butadiene (HTPB) and the Poly Tetra Methylene Glycol (PTMG) encapsulated with different concentrations of carbon nanofiber (CNF) in a cross-linked shape memory polyurethane (PU) matrix. By introducing the optimum concentration of the nanofiller with the PU matrix, we can improve essential properties of PU composites such as morphology, mechanical flexibility, as well as shape memory properties, which are considered the crucial requirement for the effective design of PU composites for a precise application. Two compositions of PU composites were prepared by encapsulating CNF, viz. PU-0.1CNF and PU-0.5CNF, the content of CNF being 1 wt.% and 5 wt.%, respectively. Morphological, thermal, and mechanical studies of these two PU composites show that CNF is homogeneously blended within the PU matrix and well dispersed. The thermal stability of prepared polymer films was evaluated with the help of Thermo-Gravimetry, indicating increased stability with the addition of CNF nanofillers. DSC analysis helps to determine the glass transition temperature (Tg ) as well as the shape transition temperature (Ttrans ). The tensile study confirmed that PU-0.5CNF possesses a greater Young’s modulus value and is not constant in elastic loads. The anti-corrosion property of the prepared SMPU nanocomposite coatings coated over the SS plate was evaluated using a 3.0 wt% NaCl (simulated seawater) solution. Extrapolation of Tafel plots and electrochemical impedance spectroscopy (EIS) provided a higher value of positive corrosion potential (Ecorr ) and a lower value of corrosion current (Icorr ). The electrochemical experiment results demonstrated that PU-0.1CNF nanocomposite coating on SS has better anti-corrosive properties and protection efficiency (PEF% = 98.43%) and behaves like a physical barrier to resist corrosion. These HTPB/PTMG PU nanocomposites exhibit excellent shape memory properties and have a unique composition having both the properties of anti-corrosion and shape memory effects. The results show that by properly selecting the composition we can tailor-make a PU having both anticorrosion and shape memory properties.

Syringic acid ameliorates testicular oxidative stress via the conservation of endogenous antioxidant markers and inhibition of the activated Nrf2-Keap1-NQO1-HO1 signaling in methyl cellosolve-administered rats

IntroductionSyringic acid (SYRAC) isolated from Ban Lan Gen or Isatis root, a famous Chinese traditional medicine is known to possess antiendotoxic effect. Methyl cellosolve (MCE) on the other hand, is an important constituent of car brake fluids, pesticides, inks, paints, and liquid soaps, rendering humans inevitable to its exposure. MethodsThis study therefore investigated the effect of SYRAC treatments on MCE-induced testicular oxidative stress in rats. Six (6) groups of five (5) rats each were involved in this study that lasted for 30 days. The first group was the control that contained rats served food and water throughout, the second group were administered 100 mg/kg body weight of MCE everyday for 30 days, the third, fourth, and fifth group were treated same way as rats in second group but were treated with 25, 50, and 75 mg/kg body weight of SYRAC respectively for 30 days, while rats in the sixth group were administered 75 mg/kg body weight of SYRAC only. ResultsAt the end of administrations, RTW, testicular GSH level, and activities of GPx, GST, CAT, and SOD were significantly decreased, while MDA, total mRNA expressions of HO-1, NQO1, Keap1, and Nrf2 were significantly increased by MCE compared with control. Compared with MCE only, treatments with SYRAC significantly increased the testicular levels of NO and GSH, as well as activities of GPx, GST, SOD, and CAT, while MDA, mRNA expressions of Keap1, NQO1, Nrf2, and HO-1 were significantly decreased. ConclusionConclusively, MCE-induced testicular oxidative stress was recorded. SYRAC demonstrated a gonadoprotective effect by maintaining the normal levels of the endogenous antioxidants and inhibiting MECE-induced Nrf2 activation and ARE-dependent genes in rats.

Light- and Redox-Responsive Block Copolymers of mPEG-SS-ONBMA as a Smart Drug Delivery Carrier for Cancer Therapy.

The development of stimuli-responsive polymeric micelles for targeted drug delivery has attracted much research interest in improving therapeutic outcomes. This study designs copolymers responsive to ultraviolet (UV) light and glutathione (GSH). A disulfide linkage is positioned between a hydrophilic poly(ethylene glycol) monomethyl ether (mPEG) and a hydrophobic o-nitrobenzyl methacrylate (ONBMA) to yield amphiphilic copolymers termed mPEG-SS-pONBMA. Three copolymers with different ONBMA lengths are synthesized and formulated into micelles. An increase in particle size and a decrease in critical micelle concentration go together with increasing ONBMA lengths. The ONB cleavage from mPEG-SS-pONBMA-formed micelles results in the transformation of hydrophobic cores into hydrophilic ones, accelerating drug release from the micelles. Obvious changes in morphology and molecular weight of micelles upon combinational treatments account for the dual-stimuli responsive property. Enhancement of a cell-killing effect is clearly observed in doxorubicin (DOX)-loaded micelles containing disulfide bonds compared with those containing dicarbon bonds upon UV light irradiation. Collectedly, the dual-stimuli-responsive mPEG-SS-pONBMA micelle is a better drug delivery carrier than the single-stimuli-responsive mPEG-CC-pONBMA micelle. After HT1080 cells were treated with the DOX-loaded micelles, the high expression levels of RIP-1 and MLKL indicate that the mechanism involved in cell death is mainly via the DOX-induced necroptosis pathway.

Nanomedicines Bearing an Alkylating Cytostatic Drug from the Group of 1,3,5-Triazine Derivatives: Development and Characterization.

Cancer is still one of the major diseases worldwide. The discovery of new drugs and the improvement of existing ones is one of the areas of priority in the fight against cancer. Dioxadet ([5-[[4,6-bis(aziridin-1-yl)-1,3,5-triazin-2-yl]amino]-2,2-dimethyl-1,3-dioxan-5-yl]methanol) represents one of the promising 1,3,5-triazine derivatives and has cytostatic activity towards ovarian cancer. In this study, we first report the development of dioxadet-bearing nanomedicines based on block-copolymers of poly(ethylene glycol) monomethyl ether (mPEG) and poly(D,L-lactic acid) (PLA)/poly(ε-caprolactone) (PCL) and then conduct an investigation into their characteristics and properties. The preparation of narrow-sized nanoparticles with a hydrodynamic diameter of 100-120 nm was optimized using a nanoprecipitation approach. Thoughtful optimization of the preparation of nanomedicines was carried out through adjustments to the polymer's molecular weight, the pH of the aqueous medium used for nanoprecipitation, the initial drug amount in respect to the polymer, and polymer concentration in the organic phase. Under optimized conditions, spherical-shaped nanomedicines with a hydrodynamic diameter of up to 230 nm (PDI < 0.2) containing up to 592 ± 22 μg of dioxadet per mg of polymer nanoparticles were prepared. Study of the drug's release in a model medium revealed the release up to 64% and 46% of the drug after 8 days for mPEG-b-PLA and mPEG-b-PCL, respectively. Deep analysis of the release mechanisms was carried out with the use of a number of mathematical models. The developed nanoparticles were non-toxic towards both normal (CHO-K1) and cancer (A2780 and SK-OV-3) ovarian cells. A cell cycle study revealed lesser toxicity of nanomedicines towards normal cells and increased toxicity towards cancer cells. The IC50 values determined for dioxadet nanoformulations were in the range of 0.47-4.98 μg/mL for cancer cells, which is close to the free drug's efficacy (2.60-4.14 μg/mL). The highest cytotoxic effect was found for dioxadet loaded to mPEG-b-PCL nanoparticles.

Hole concentration modulated gas sensor for selective detection of 2-methoxy ethanol

The inhaling rate of toxic gases in daily life is increasing alarmingly; in turn, human health is in question. To resolve this dilemma, the possible remedy is the early detection and adequate regulation of VOCs in the atmosphere via sensors. Therefore, the investigation focused on developing a gas sensor for sensing several VOCs and flourished with a highly selective C3H8O2 gas sensor at room temperature. In-depth structural, elemental, and morphological analysis followed by the sensing test affirmed the enhanced C3H8O2 detection performance of Ag–NiO over pure NiO. The nanosized sphere formation was confirmed via XRD and TEM characterizations alongside the effect of sintered temperature on the shape and crystallite size. Moreover, the XPS examined the combined effect of sintering temperature and doping on the synthesized nanostructures and optimized the exact temperature as 500 °C because of the improved hole concentration. The Ag–NiO(500 °C) exhibited appealing sensing characteristics, specifically, a high response of 6491.57 for 100 ppm C3H8O2 at room temperature. The sensor displayed a quick response and recovery (10 s,10 s) C3H8O2 alongside long-term repeatability and stability; it showed practical implementation in real-time scenarios.

Methyl cellosolve toxicity and a review of recent treatment outcomes

Methyl cellosolve toxicity and a review of recent treatment outcomes

Effect of syringic acid on steroid and gonadotropic hormones, hematological indices, sperm characteristics and morphologies, and markers of tissue damage in methyl cellosolve-administered rats

Methyl cellosolve (MTC) is an established gonadotoxic and hematotoxic compound that is commonly and universally utilized in herbicide, liquid soap, stain, dye, paint, and brake fluid manufacturing industries as a solvent. Due to its wide range usage, this study therefore investigated the effect of syringic acid (SYAC) on hematological indices, sperm characteristics and morphologies, and markers of tissue damage in MTC administered male Wistar rats. Thirty (30) rats divided into six groups were used. Rats in group 1 served as control, those in group 2 were administered MTC for 30 consecutive days, those in groups 3, 4, and 5 were treated with 25, 50, and 75 mg/kg body weight of SYAC respectively also for 30 consecutive days immediately after each day MTC administrations, while rats in group 6 received 75 mg/kg body weight of SYAC only throughout. Compared with control, administrations of MTC resulted in a significant decrease in spermatozoa count, number of normal and live spermatozoa, Hb count, MCH, MCHC, serum TC, and LH, while number of abnormal spermatozoa, RBC and WBC counts, activities of serum AST, ALT, GGT, LDH, and ADH were significantly increased. Treatments with 25 mg/kg of SYAC significantly reduced the RBC and WBC counts, serum activities of AST, ALT, GGT, and increased TC concentration. Treatments with 50 mg/kg SYAC significantly lowered the number of abnormal spermatozoa, RBC count, activities of serum ALT, AST, LDH, ADH, and increased the number of normal spermatozoa, MCV, MCH, and MCHC, while 75 mg/kg of SYAC significantly decreased the serum activities of AST, ALT, GGT, LDH, ADH, and increased serum TC concentration. Findings from this study have revealed the hepatoprotective effect of SYAC at all doses investigated but did not confer spermatoprotection and hematoprotection against MTC-induced toxicities, and looking at the 3 doses investigated, 50 mg/kg of SYAC yielded the best effect.

Nonaqueous (amine + glycol ether) solvents for energy-efficient CO2 capture: New insights into phase change behaviors and assessment of capture performance

Nonaqueous amine-based absorbents, particularly liquid biphasic solvents, have recently received increasing attention due to the potential for reducing the energy penalty of CO2 capture. In this work, a series of glycol ethers were used as cosolvents dissolving primary and secondary alkanolamines. Phase transition behavior, CO2 absorption and desorption characteristics have been investigated for the nonaqueous 5.0 M amine blends. Different phase behaviors upon CO2 absorption were discussed and well explained by the polarity change and the solubility parameter interaction distance (SPID) of components and the reaction products. Regeneration energy requirement was also experimentally estimated and compared with the reference aqueous monoethanolamine (MEA). The species in the CO2-loaded solution play a central role in regulating phase separation behaviour and CO2 capture performance. A defined SPID value was recommended to predict the monophasic and the biphasic states. Advanced systems of 2-(methylamino)ethanol (MAE) with diethylene glycol dimethyl ether (DEGDME) as liquid biphasic solvent and MAE with ethylene glycol monomethyl ether (EGME) as single phase solvent were proposed for energy-efficient CO2 capture. Among the systems investigated, MAE/EGME has the lowest regeneration energy consumption estimated at about 1.75 MJ kg−1 CO2 captured. The ionic carbonated products of alkanolamines can trigger the phase change behaviour due to their limited solubility in the more hydrophobic and weakly polar DEGDME, resulting in two opposite phases enriched in different components. Benefiting from the high enrichment (>95 %) of CO2 captured in the lower phase and the large cyclic capacity, MAE/DEGDME biphasic solvent can reduce the energy consumption by 50–59 % compared with aqueous MEA.

Organometallic S-arylation Reagents for Rapid PEGylation of Biomolecules.

Bioconjugation techniques for biomolecule-polymer conjugation are numerous; however, slow kinetics and steric challenges generally necessitate excess reagents or long reaction times. Organometallic transformations are known to circumvent these issues; yet, harsh reaction conditions, incompatibility in aqueous media, and substrate promiscuity often limit their use in a biological context. The work reported herein demonstrates a facile and benign organometallic Au(III) S-arylation approach that enables the synthesis of poly(ethylene glycol) monomethyl ether (mPEG)-protein conjugates with high efficiency. Isolable and bench-stable 2, 5, and 10 kDa mPEG-Au(III) reagents were synthesized via oxidative addition into terminal aryl iodide substituents installed on mPEG substrates with a (Me-DalPhos)Au(I)Cl precursor. Reaction of the isolable mPEG-Au(III) oxidative addition complexes with a cysteine thiol on a biomolecule resulted in facile and selective cysteine arylation chemistry, forging covalent S-aryl linkages and affording the mPEG-biomolecule conjugates. Notably, low polymer reagent loadings were used to achieve near quantitative conversion at room temperature in 1 min due to the rapid kinetics and high chemoselectivity of this Au-based bioconjugation approach. Therefore, this work represents an important addition to the protein-polymer conjugation chemical toolbox.

ICAR ATRP-induced surface self-assembly in the fabrication of the surface nanostructures

Polymerization induced surface self-assembly (PISSA) technology is a state-of-the-art method in the fabrication of the hierarchical surface nanostructures. Previously, we demonstrated that reversible addition−fragmentation chain transfer (RAFT) polymerization-based PISSA could be used to construct hierarchical surface nanostructures on the silica particles. Atom transfer radical polymerization (ATRP) has many advantages, especially in the synthesis of the macroinitiator. In this research initiators for continuous activator regeneration (ICAR) ATRP-induced PISSA approach is used to fabricate surface nanostructures. Poly(ethylene glycol) (PEG) macroinitiator and poly(oligo(ethylene glycol) monomethyl ether methacrylate-co-2-(2-bromoisobutyrnyloxy) ethyl methacrylate) (P(OEGMA-co-BIEM)) polymer brush macroinitiator on silica particles are used to initiate ATRP of styrene in methanol/water mixture. With the chain extensions, POEGMA-g-PS graft copolymer brushes and “free” PEG-b-PS block copolymer chains make surface coassembly into surface nanostructures. With an increase in monomer feeding ratio, the surface morphology gradually changes from small-sized spherical surface micelles (s-micelles), to big-sized s-micelles, and to asymmetric layered structures. Kinetics studies indicate that with an increase in monomer conversion there is a transition from homogeneous to heterogeneous polymerization.

Extenders and Cryosolutions for Grumatã (Prochilodus Vimboides) Sperm Preservation

BACKGROUND: Prochilodus vimboides populations are being reduced in rivers due to changes in their habitat, overfishing, urbanization, and pollution. OBJECTIVE: To evaluate the effect of sperm extender solutions for short-term storage and cryosolutions for freezing sperm of Prochilodus vimboides . MATERIALS AND METHODS:For short-term storage, the sperm was diluted in 0.9% NaCl, 1.2% NaCl, 5%glucose, 5% BTS ® , or 6% MIII ® . Sperm motility was evaluated after 0, 24, 48, and 72 h of short-term storage at 4-6ºC. For cryopreservation, sperm samples were diluted in the same extenders and factorially combined with three cryoprotectants (dimethylsulfoxide, methyl glycol, and ethylene glycol). After thawing, sperm motility and oxidative stress parameters were evaluated. RESULTS: Dilution of samples in BTS® preserved sperm motility >40% for up to 48 h. Samples cryopreserved in 5% glucose and methylglycol presented higher sperm motility, lower catalase, and lipid peroxidation activities.CONCLUSION: Prochilodus vimboides sperm can be cooled for up to 48 h in an extender solution of 5% BTS ® and cryopreserved in 5% glucose and methyl glycol.

Synthesis of stimulus-responsive ABC triblock fluorinated polyether amphiphilic polymer and application as low toxicity smart drug carrier

Polymeric surfactants based on hydrocarbon polyether structure, have been used in many pharmaceutical formulations and drug delivery for many years. However, nowadays, developing novel drugs is often accompanied by introducing fluoride atom, inhibiting the application scope of traditional hydrocarbon surfactants. Thus, we argued it is necessary to develop novel fluorinated polyether polymeric surfactant. Herein, poly(ethylene glycol) monomethyl ether was used to initiate the living cationic polymerization of fluorinated epichlorohydrin (EPTF) prepared by our group and (R)-glycidyl butyrate to obtain a type of triblock fluorinated polyether amphiphilic polymer, which possesses stimulus-responsive characteristic in the presence of acid and enzyme. The structure of this triblock fluorinated polyether amphiphilic polymer was confirmed by spectroscopic data. And the critical micelles concentration of this surfactant was relatively low representing their excellent surface activity. CCK-8 test showed that this triblock fluorinated polyether amphiphilic polymer displayed no toxic effect on NIH3T3 cells even its concentration reached to 1 g/L. Therefore, we design and obtain a kind of triblock fluorinated polyether amphiphilic polymer possessing low toxicity and stimulus-responsive characteristic which can also be used to improve the solubility of baicalin.

Effect of Au and Ag nanoparticles addition on the morphological, structural and optical properties of ZnO thin films deposited by sol-gel method

In the present study, ZnO thin films were deposited on quartz substrates by sol-gel spincoating method. Zinc-diacetate ((Zn(CH3COO)2.2H2O), diolamine (DEA) (HN(CH2CH2OH)2) and ethylene glycol monomethyl ether (CH3OCH2CH2OH) were used as a precursor, stabilizer agent, and solvent, respectively. Au and Ag NPs were synthesized by (PLAL) technique using “Q-Switched ND-YAG laser” system with laser parameters (520 mJ laser energy, 1064 nm wavelength, 450 laser pulses, and 1Hz frequency). The volumetric ratios of ZnO source solution to Au and Ag colloidal solutions were 3:2 and 4:1, respectively. The morphological, structural and optical properties of ZnO thin films embedded with Au and Ag NPs were investigated. The patterns of x-ray diffraction (XRD) showed peaks indexed to (100), (002) and (101) planes for ZnO and (111), (200) and (220) for Au and Ag NPs. The surface morphology of the films was examined by FESEM and the Raman spectra of ZnO thin films embedded with Ag and Au NPs were investigated. Furthermore, the optical properties of the films were analyzed by UV-Vis spectroscopy measurements. The optical band gap of the films increased with increasing the volumetric ratios of ZnO embedded with Au and Ag NPs.

Polyoxymethylene dimethyl ethers synthesis from methanol and formaldehyde solution over one-pot synthesized spherical mesoporous sulfated zirconia

The synthesis of polyoxymethylene dimethyl ethers as an ideal diesel fuel additive is the current hot topic of modern petrochemical industry for their expedient properties in mitigating air pollutants emission during combustion. In this work, a series of spherical sulfated zirconia catalysts were prepared by a one-pot hydrothermal method assisted with surfactant cetyltrimethylammonium bromide (CTAB). The prepared sulfated zirconia catalysts were used to catalyze PODEn synthesis from methanol and formaldehyde solution. Various characterization (XRD, BET, SEM, TGA, NH3-TPD, FTIR, and Py-IR) were employed to elaborate the structure–activity relationship of the studied catalytic system. The results demonstrated that S/Zr molar ratio in precursor solution played an effective role on catalyst morphology and acidic properties, where the weak Brønsted acid sites and strong Lewis acid sites were favorable to the conversion of methanol and formation of long-chain PODEn, respectively. The reaction parameters such as catalyst amount, molar ratio of FA/MeOH, reaction time, temperature and pressure were optimized. The speculated reaction pathway for PODEn synthesis was proposed based on the synergy of Brønsted and Lewis acid sites, which suggested that Brønsted and Lewis acid sites might be advantageous to the activation of polyoxymethylene hemiformals [CH3(OCH2)nOH] and methylene glycol (HOCH2OH), respectively.

Biobased diglycidyl ether diphenolates: Effect of the ester moiety on fragrance oil microencapsulation by interfacial polymerization

Health risks are associated with capsule-forming synthetic chemicals such as formaldehyde, isocyanates, and bisphenol A (BPA). This work is focused on using safe biobased molecules to build capsule walls for oil encapsulation. Cellulose-derived diphenolic acid was converted into a series of diglycidyl ether n-alkyl diphenolates (DGEDP-esters). Interfacial polymerization of oil-soluble DGEDP-esters and water-soluble amine hardeners, hexamethylenediamine (HMDA) and chitosan oligosaccharide (COS), were used to build capsule walls. DGEDP-esters with small methyl and polar monomethyl ethylene glycol (DGEDP-ME and DGEDP-MG, respectively) are most reactive forming compact crosslinked capsules with high microencapsulation efficiency (EE of 97% and 94.3%) and good stability (oil leaking was ≤ 15.7% after acidification, and ≤ 64.2% after sonication). With increased hydrophobicity of the DGEDP ester moiety, deformed capsules with low EE (63 – 87%) and poor stability (oil leaking was ≥ 18.4% after acidification, and ≥ 81.8% after sonication) were obtained. Oil encapsulated with DGEDP-esters exhibits oil release of 0.5 – 8% at day 30 (45 °C and 11 kPa). The use of COS as the hardener yields capsules with EE (88.3 – 94%) and higher oil release (9–15% at day 30) compared to HMDA, but the acid stability was remarkably improved (oil leaking ≤ 3.7%). Cytotoxicity tests suggest that capsules formed with DGEDP-ME and HMDA or COS show very low cytotoxicity against human breast cancer cells and human fibroblasts cells (cell viability of 87–102% after 24 h exposure at capsule concentration of 2 mg/mL). These observations demonstrate that the structures of DGEDP epoxy monomers and amine hardeners have significant effects. Preferred DGEDP ester groups were methyl and mono-methoxy, and effective capsule formation was achieved using either HMDA or COS, the latter providing the advantage of being a readily renewable biobased multifunctional amine.

Construction of Enzyme-Responsive Micelles Based on Theranostic Zwitterionic Conjugated Bottlebrush Copolymers with Brush-on-Brush Architecture for Cell Imaging and Anticancer Drug Delivery.

Bottlebrush copolymers with different chemical structures and compositions as well as diverse architectures represent an important kind of material for various applications, such as biomedical devices. To our knowledge, zwitterionic conjugated bottlebrush copolymers integrating fluorescence imaging and tumor microenvironment-specific responsiveness for efficient intracellular drug release have been rarely reported, likely because of the lack of an efficient synthetic approach. For this purpose, in this study, we reported the successful preparation of well-defined theranostic zwitterionic bottlebrush copolymers with unique brush-on-brush architecture. Specifically, the bottlebrush copolymers were composed of a fluorescent backbone of polyfluorene derivate (PFONPN) possessing the fluorescence resonance energy transfer with doxorubicin (DOX), primary brushes of poly(2-hydroxyethyl methacrylate) (PHEMA), and secondary graft brushes of an enzyme-degradable polytyrosine (PTyr) block as well as a zwitterionic poly(oligo (ethylene glycol) monomethyl ether methacrylate-co-sulfobetaine methacrylate) (P(OEGMA-co-SBMA)) chain with super hydrophilicity and highly antifouling ability via elegant integration of Suzuki coupling, NCA ROP and ATRP techniques. Notably, the resulting bottlebrush copolymer, PFONPN9-g-(PHEMA15-g-(PTyr16-b-P(OEGMA6-co-SBMA6)2)) (P2) with a lower MW ratio of the hydrophobic side chains of PTyr and hydrophilic side chains of P(OEGMA-co-SBMA) could self-assemble into stabilized unimolecular micelles in an aqueous phase. The resulting unimolecular micelles showed a fluorescence quantum yield of 3.9% that is mainly affected by the pendant phenol groups of PTyr side chains and a drug-loading content (DLC) of approximately 15.4% and entrapment efficiency (EE) of 90.6% for DOX, higher than the other micelle analogs, because of the efficient supramolecular interactions of π–π stacking between the PTyr blocks and drug molecules, as well as the moderate hydrophilic chain length. The fluorescence of the PFONPN backbone enables fluorescence resonance energy transfer (FRET) with DOX and visualization of intracellular trafficking of the theranostic micelles. Most importantly, the drug-loaded micelles showed accelerated drug release in the presence of proteinase K because of the enzyme-triggered degradation of PTyr blocks and subsequent deshielding of P(OEGMA-co-SBMA) corona for micelle destruction. Taken together, we developed an efficient approach for the synthesis of enzyme-responsive theranostic zwitterionic conjugated bottlebrush copolymers with a brush-on-brush architecture, and the resulting theranostic micelles with high DLC and tumor microenvironment-specific responsiveness represent a novel nanoplatform for simultaneous cell image and drug delivery.

Synthesis, structural and DFT studies on thiosemicarbazone-based dioxomolybdenum(VI) complexes with co-ligands

5-Chloro-2-hydroxybenzophenone-S-methyl-4-phenylthiosemicarbazone (Η2L1) was synthesized from 4-phenylthiosemicarbazide. Reaction of Η2L1 with [bis(acetylacetonato)dioxomolybdenum(VI)] gave the dioxomolybdenum(VI) complexes with [MoO2(L1)(L2)] composition where L2 is n-pentanol, ethylene glycol monomethyl ether, ethyl acetate, isoamyl alcohol, pyridine, or γ-picoline. The structures of the stable solid complexes were elucidated using elemental analysis, electronic, FTIR, and 1H NMR spectra. Crystallographic analysis of [MoO2(L1)(n-pentanol)] (1) clearly indicated the O,N,N-chelating thiosemicarbazone backbone and the distorted octahedral environment of the molybdenum atom. Complex 1 crystallizes in the monoclinic system with P21/n space group and Z = 4. Moreover, the quantum chemical calculations supporting the experimental data of 1–6 are also reported in this study. Geometric optimization and theoretical vibrational spectra calculations of the complexes were performed by using the B3LYP density functional level of theory with LANL2DZ basis set employing density functional theory (DFT). Also, the non-covalent interaction (NCI) plot index analysis reveals the presence of different kinds of non-covalent interactions in [MoO2(L1)(n-pentanol)] (1).

Reusable Pd-PolyHIPE for Suzuki-Miyaura Coupling.

Palladium was immobilized on a highly porous copolymer of 4-vinylpyridine and divinylbenzene (polyHIPE—poly(high internal phase emulsion)) using palladium(II) acetate to obtain PolyPy-Pd with 6.1 wt % or 0.57 mmol Pd/g. The immobilized catalyst was able to catalyze the coupling of iodobenzene and phenylboronic acid in ethylene glycol monomethyl ether/water (3:1) within 4 h at rt and complete conversion was observed when 2.5 mol % of Pd per PhI was used. The reaction tolerated a wide range of substituents on the aromatic ring. Iodobenzene derivatives with electron-withdrawing substituents showed higher reactivity, while the opposite was true for the phenylboronic acid series. The polyHIPE-supported Pd catalyst was also used for the direct conversion of phenylboronic acid to biphenyl through an iodination/coupling reaction sequence. The recyclability of the heterogeneous catalyst was also optimized, and by finding a suitable combination of solvents for the loading of Pd, the reaction, and the isolation of the product, the solid-supported catalyst was completely regenerated and used in the next reaction with the same activity.