Schlenk Flask Research Articles

Synthesis of zirconium-based metal-organic framework under mild conditions and its application to the removal of cationic and anionic dyes from wastewater

Water resources contaminated by industrial dyes can pose a significant threat to the environment and human health. Herein, we conducted a study on the removal of cationic and anionic dyes, such as methylene blue (MB) and methyl orange (MO), using MIL-140A, a zirconium-based metal-organic framework. MIL-140A is synthesized in a Schlenk flask at 120 °C, whereas its conventional synthesis route involves a teflon-sealed autoclave at 220 °C, highlighting the cost reduction and lower equipment requirements of the low-temperature synthesis. The structure of MIL-140A is characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM), and nitrogen adsorption techniques. The optimal pH for the adsorption of two dyes by MIL-140A is pH 5–8 for MB and pH 3 for MO. The adsorption equilibrium can be reached within 60 min at room temperature, and the adsorption of both dyes on MIL-140A follows pseudo-second-order kinetics and Langmuir isotherm, and the maximum adsorption capacity of MO and MB by MIL-140A were 163.6 and 89.2 mg/g, respectively. Thermodynamic studies indicate an entropy-driven spontaneous process. The adsorption mechanism of MO and MB on MIL-140A is investigated using FT-IR and X-ray photoelectron spectroscopy. The adsorption of MO involves coordination between Zr and sulfonate, while MB adsorption occurs via π-π interactions. Additionally, MIL-140A exhibits better removal efficiency for MO from lithium battery wastewater compared to MB, primarily due to stronger coordination interactions than π-π interactions. These findings demonstrate that MIL-140A is a promising adsorbent for effectively removing both anionic and cationic dyes from water resources.

Martin Silicates as Partners in Photoredox/Ni Dual Catalysis for the Installation of CH3, CH2D, CD2H, CD3and13CH3Groups onto (Hetero)Arenes

Martin Silicates as Partners in Photoredox/Ni Dual Catalysis for the Installation of CH₃, CH₂D, CD₂H, CD₃and¹³CH₃Groups onto (Hetero)Arenes

Arylene Diimide Derivatives as Anolyte Materials with Two-Electron Storage for Ultrastable Neutral Aqueous Organic Redox Flow Batteries

Arylene Diimide Derivatives as Anolyte Materials with Two-Electron Storage for Ultrastable Neutral Aqueous Organic Redox Flow Batteries

Visible-Light-Induced Decarboxylative Fluorination of Aliphatic Carboxylic Acids Catalyzed by Iron.

An efficient and inexpensive protocol for the direct decarboxylative fluorination of aliphatic carboxylic acids catalyzed with iron salts under visible light is presented. This new method allows the facile fluorination of a diverse array of carboxylic acids even on gram scale using a Schlenk flask without loss of efficiency. Mechanistic studies suggest that the photoinduced ligand-to-metal charge transfer process enables the generation of the key step to generate the carboxyl radical intermediates.

2022 ACS National Award winners—Part II

ACS Award for Research at an Undergraduate Institution: Chip Nataro Sponsor: Research Corporation for Science Advancement Citation: For outstanding achievements in the study of bis(phosphino)metallocene compounds accomplished with undergraduate researchers and for his dedication to mentoring students and faculty Current position: Marshall R. Metzgar Professor of Chemistry and head of Chemistry Department, Lafayette College Education: BS, chemistry, Messiah College; PhD, inorganic chemistry, Iowa State University Nataro on the most rewarding part of his job: “The incredible students I have worked with. From their first struggle putting a septum on a Schlenk flask, to wherever their careers take them, I am proud to have had a small part in their development and excited for their success after Lafayette. ‘We are what they grow beyond’ says Master Yoda. I hope I have been able to help them grow beyond me to their fullest potential.” What Nataro’s colleagues say: “Chip is one of

An Unconventional trans - exo -Selective Cyclization of Alkyne-Tethered Cyclohexadienones Initiated by Rhodium(III)-Catalyzed C–H Activation via Insertion Relay

Different from the established trans-endo-selective cyclization of alkyne-tethered electrophiles that involve an E/Z isomerization process, herein, the authors present a novel strategy to allow tra...

ATRP of Methyl Acrylate by Continuous Feeding of Activators Giving Polymers with Predictable End-Group Fidelity.

Atom transfer radical polymerization (ATRP) of methyl acrylate (MA) was carried out by continuous feeding of Cu(I) activators. Typically, the solvent, the monomer, the initiator, and the CuBr2/Me6TREN deactivator are placed in a Schlenk flask (Me6TREN: tris[2-(dimethylamino)ethyl]amine), while the CuBr/Me6TREN activator is placed in a gas-tight syringe and added to the reaction mixture at a constant addition rate by using a syringe pump. As expected, the polymerization started when Cu(I) was added and stopped when the addition was completed, and polymers with a narrow molecular weight distribution were obtained. The polymerization rate could be easily adjusted by changing the activator feeding rate. More importantly, the loss of chain end-groups could be precisely predicted since each loss of Br from the chain end resulted in the irreversible oxidation of one Cu(I) to Cu(II). The Cu(I) added to the reaction system may undergo many oxidation/reduction cycles in ATRP equilibrium, but would finally be oxidized to Cu(II) irreversibly. Thus, the loss of chain end-groups simply equals the total amount of Cu(I) added. This technique provides a neat way to synthesize functional polymers with known end-group fidelity.

Confounding contaminants in mass spectrometric reaction monitoring

Reactions carried out in the presence of rubber septa run the risk of additives being leached out by the solvent. Normally, such species are present at low enough levels that they do not interfere with the reaction significantly. However, when studying reactions using sensitive methods such as mass spectrometry, the appearance of even trace amounts of material can confuse dynamic analyses of reactions. A wide variety of additives are present in rubber along with the polymer: antioxidants, dyes, detergent, and vulcanization agents, and these are all especially problematic in negative ion mode. A redesigned Schlenk flask for pressurized sample infusion (PSI) is presented as a means of practically eliminating the presence of contaminants during reaction analyses.

Silver Chloride/Triphenylphosphine-Promoted Carboxylation of Arylboronic Esters with Carbon Dioxide at Atmospheric Pressure

Aim and Objective: The carboxylation of organoboronic esters with CO2 is an attractive way of preparing the functionalized carboxylic acid derivatives. For the silver-catalyzed carboxylation of arylboronic esters with CO2, sensibility of catalytic system to CO2 pressure resulted in a high CO2 pressure required in the reaction. This work focuses on solving this problem and promoting this transformation under atmospheric CO2 pressure. Material and Method: Arylboronic esters were synthesized according to the published procedure. Arylorganic esters, silver compound, base, PPh3 and solvent were introduced into a 25 mL Schlenk flask. Then, the gasexchanging operation via a “freeze-pump-thaw” method was conducted. After being enclosed with a CO2 balloon, the resulting mixture was stirred at 70oC for 12 h. Then, the reaction was quenched by 1 M HCl and extracted with ethyl acetate. The yields of the corresponding carboxylic acids were determined by GC. The structures of products were confirmed by NMR and GC-MS. Results: The carboxylation of arylboronic esters with ambient CO2 was achieved on the basis of the silver chloride/triphenylphosphine system by using cesium carbonate as the base and dimethyl sulfoxide as the solvent. Through this protocol, various functionalized carboxylic acids were synthesized in 85-99% yields. Conclusion: The silver-catalyzed carboxylation of arylboronic esters with ambient CO2 was established. This approach represents an alternative way to prepare carboxylic acids derivatives from the organoboron compounds with CO2 under mild reaction conditions. Keywords: Carbon dioxide, arylboronic ester, carboxylation, carboxylic acid, silver catalysis, atmospheric pressure.

Metal‐containing ionic liquid‐based, uncharged–charged diblock copolymers that form ordered, phase‐separated microstructures and reversibly coordinate small protic molecules

Metal‐containing ionic liquid‐based, uncharged–charged diblock copolymers that form ordered, phase‐separated microstructures and reversibly coordinate small protic molecules

Synthesis and electrochemical performance of colloidal MoS2 nanosheets as an anode material in sodium ion battery

MoS2 nanosheets by utilizing MoO and Mo(CO)6 as a precursor sources of molybdenum were prepared by a colloidal route at 270°C in Schlenk flask under the inert atmosphere. The as obtained layered and wrinkled nanosheets were then applied as anode materials in a sodium ion batteries (NIBs) in order to elucidate the electrochemical performances, where an excellent first and second charge/discharge capacities of 150/310mAhg−1, 125/148mAhg−1 with a good stability up to ∼30 cycles were obtained with the precursor source of Mo(CO)6. However the MoO employed precursor based nanosheets shows a substantially low first and second charge discharge capacities of 12/37mAhg−1 and 10/14mAhg−1. The FE-SEM and XRD shows the wrinkled layered structures in both the precursors with XRD pattern more prominent in the Mo(CO)6 precursor with 2θ peaks at 34°, 36°, and 59°. The excellent performance of nanosheets in the Mo(CO)6 precursor source could be ascribed to the efficient breakage of carbonyl ligands to form a well super saturated monomers followed by well crystallinity with defect free, stable morphology which could effectively withstand expansion/contraction occurring during the successive sodium ion insertion/extraction process.

Rhodium-Catalyzed Selective Mono- and Diamination of Arenes with Single Directing Site "On Water".

A Rh(III)-catalyzed selective C-H amination of 2-phenylpyridine derivatives is reported. With pyridine as a directing group, the reaction has high mono- or diamination selectivity, and a wide range of effective substrates, including electron-deficient and -rich aryl azides. Water helps to promote C-H activation, and the concept of a water promoted rollover mechanism is postulated for the diamination step. The reactions were conducted using a Schlenk flask and proceeded smoothly "on water" under atmospheric conditions with nitrogen gas as the only byproduct.

Potassium tert-Butoxide-Catalyzed Dehydrogenative Cross-Coupling of Heteroarenes with Hydrosilanes

A. 1-Methyl-2-(triethylsilyl)-1H-indole (2). An oven-dried 100-mL round-bottom Schlenk flask is equipped with a Teflon-coated magnetic stir bar (25 x 8 mm) and capped with a rubber septum (Note 1). The side arm of the flask is connected to Schlenk line and the flask is cooled to room temperature under vacuum and back-filled with nitrogen. Potassium tert-butoxide (1.34 g, 12.0 mmol, 0.2 equiv) is added to the flask under positive nitrogen flow (Notes 2 and 3), and then the flask is evacuated and back-filled with nitrogen three times. N-Methylindole (7.48 mL, 7.86 g, 60.0 mmol, 1.0 equiv) and triethylsilane (28.6 mL, 20.82 g, 179.5 mmol, 3.0 equiv) are added sequentially via syringe through the septum, resulting in a yellow heterogeneous mixture (Figure 1). After the septum is replaced with a glass stopper (Note 4), the reaction mixture is degassed (Note 5) and stirred at 45 oC for 76 h (Note 6), resulting in a dark purple solution. The heating bath is removed and the reaction mixture is allowed to cool to ambient temperature (~25 oC), then anhydrous diethyl ether (30 mL) is added slowly while stirring (Note 7).

Facile synthesis of low cost anatase titania nanotubes and its electrochemical performance

This work demonstrates a simple, large scale, cost effective facile route to a well crystallized only anatase TiO2 nanotube synthesized in Schlenk flask at 120°C for 12h in the 8M KOH solution (TNTK) without a Teflon line autoclaves. For the first time all the XRD peaks at 2θ degrees of 25.39, 39.92, 48.11, 54.04, 55.03, 62.73, 68.97, 70.46, 75.48 corresponding to (101), (004), (200), (105), (211), (204), (116), (220), and (215) appeared in the final products contrary to the hydrothermal method where one/two anatase phases, often accompanied by a 2θ peaks at 14.5°. The as prepared nanotubes shows an outer diameter of ∼10nm and inner diameter of ∼4.4nm with a micrometers of tube lengths. It possess a high BET surface area of 203.75 m2/g with band gap of 3.70eV, whereas 8M NaOH solution (TNSNa) at the same condition gives a scattered flowered structure with tapering petals of surface area 71.5 m2/g and a mixed crystal phase of anatase/rutile and sodium hexatitanate. When these nanotubes applied as anode materials in LIBs, it shows an excellent first discharge/charge capacity of 635/240mAhg−1 and retains 164mAhg−1 after 36 cycles much higher than that of titanium dioxide nanoparticles and scattered flowers. The excellent performance can be ascribed to the 1D morphology, enhanced conductivity, fewer localized states near the band edges, high surface area and robustness of tubules which could effectively withstand expansion/contraction occurring during the lithium ion insertion/extraction process. Details of the synthesized nanotubes and electrochemical properties were characterized by HR-TEM, TEM-EDS, FE-SEM, XRD, XPS, UV-vis, electrochemical, CV, impedance and BET surface area techniques.

Simplified Real-Time Mass Spectrometric Analysis of Reactions

Dynamic information can be obtained on in-progress reactions in real time using a balloon-pressurized Schlenk flask in combination with an electrospray ionization mass spectrometer. The apparatus can be set up on a Schlenk line or in a glovebox and transported to the spectrometer, to be initiated by addition of catalyst or reactant by syringe through a septum. The system is demonstrated on palladium-catalyzed oxidation of phosphines.

Synthesis and processing of strong light absorbent iron pyrite quantum dots in polymer matrix for efficiency enhancement of bulk-heterojunction solar cell

Light absorbent FeS2 quantum dots (QDs) with an average size of ~5nm were synthesized by the colloidal method using a dodecylamine as a solvent and structure directing ligand at 215°C in a Schlenk flask. X-ray diffraction pattern and UV–vis spectra analysis show a phase pure pyrite with a band gap of 0.99eV. These QDs were blended in a polymer matrix comprising of poly(3-hexylthiophene-2,5-diyl):[6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM, 10mg:10mg) in bulk-heterojunction solar cell with loading of 10wt%, 20wt%, and 40wt% of P3HT in order to harness excess light to enhance the efficiency and balance carrier mobility in our quest to devise efficient solar cells. An enhanced efficiency of 3.62% with the 20wt% of QDs addition was achieved from the normal BHJ device of efficiency 2.32%. However, addition of 40wt% QDs shows a decreased efficiency of 1.77%. The extended light harvest induced electronic mobility and reduced recombination of electron–hole may contribute to higher efficiencies. The morphology and optoelectronic properties are characterized by TEM, XRD, UV–vis, EQE and I–V curve techniques.

Synthesis, characterization and optoelectronic properties of iron pyrite nanohusks

Poly-sized iron pyrite nanohusks with an average length of ~6nm were synthesized in ethanolamine which acts as a solvent and a surfactant at 210°C in a Schlenk flask. An X-ray diffraction pattern and Raman spectra show a cubic iron pyrite structure with prominent Raman peaks at the 339.5 and 378 positions, typical of cubic iron pyrite. UV–vis spectra show an increased band gap of 1.34eV due to quantum size effects. The synthesized semiconducting iron pyrite nanohusks owing to lighter weight and strong visible light coverage have advantages over large pyrite nanocrystals, since the larger particles usually sink down to the bottom on spin casting due to unavoidable gravity effects. When such nanohusks were applied in a bulk-heterojunction type solar cell with an n-type fullerene (PCBM), an efficiency of 0.23% was observed with a JSC of 1.4mA/cm−2, a VOC of 0.17V and a fill factor of 32. The morphology and optoelectronic properties of the synthesized nanohusks were elucidated by TEM, XRD, micro-Raman spectra, UV–vis, SEM, XPS, TEM-EDX and J–V techniques.

Synthesis and X-ray diffraction data of 4-benzyloxy-1-oxaspiro-[4.6]-undec-3-en-2-one

The 4-benzyloxy-1-oxaspiro-[4.6]-undec-3-en-2-one (C17H20O3) was prepared through a domino reaction from benzyl α-hydroxycycloheptanecarboxylate and the cumulated ylide Ph3P=C=C=O by: (i) addition and (ii) intramolecular Wittig Olefination reaction. The reaction was carried out using anhydrous toluene as solvent under an argon atmosphere in a Schlenk flask. Molecular characterization was performed by Fourier transform infrared spectroscopy, gas chromatography-mass spectrometry, (1H,13C – mono and bidimensional) nuclear magnetic resonance spectroscopy; crystallographic characterization was completed by X-ray diffraction of polycrystalline samples (XRPD). The title compound crystallized in a monoclinical system and unit-cell parameters are reported [a = 13.207(3) Å, b = 5.972(1) Å, c = 19.719(4) Å, β = 105.67(2)°, unit-cell volume V = 1497.5 (4) Å3, Z = 4]. All of the measured lines were indexed with the P21/n (No. 14) space group.

Air‐Stable, Highly Fluorescent Primary Phosphanes

Air‐Stable, Highly Fluorescent Primary Phosphanes

Pressurized Sample Infusion for the Continuous Analysis of Air- And Moisture-Sensitive Reactions Using Electrospray Ionization Mass Spectrometry

Air- and moisture-sensitive compounds pose handling difficulties for chemists requiring mass spectrometric analysis. A simple pressurized sample infusion (PSI) system for electrospray ionization mass spectrometry using a Schlenk flask is presented, which allows straightforward one-off analyses as well as continuous reaction monitoring at any temperature up to the boiling point of the solvent.