Improved Safety during Transfer of Pyrophoric <i>tert</i>-Butyllithium from Flasks with Protective Seals

A simple setup has been devised to facilitate safer transfer of air-sensitive and pyrophoric reagents from Sure/Seal bottles in a fume hood setting. The setup is composed of three parts; a sealed transfer vial, a custom bottle cap for transfer vial alignment, and a metal clip. All of the needed parts are constructed from standard laboratory equipment and by 3D printing. Titration of <i>tert</i>-butyllithium was used as an example of safe transfer of a highly pyrophoric reagent, and an instructional video has been prepared

Improved Safety during Transfer of Pyrophoric <i>tert</i>-Butyllithium from Flasks with Protective Seals

A simple setup has been devised to facilitate safer transfer of air-sensitive and pyrophoric reagents from Sure/Seal bottles in a fume hood setting. The setup is composed of three parts; a sealed transfer vial, a custom bottle cap for transfer vial alignment, and a metal clip. All of the needed parts are constructed from standard laboratory equipment and by 3D printing. Titration of <i>tert</i>-butyllithium was used as an example of safe transfer of a highly pyrophoric reagent, and an instructional video has been prepared

Redox Grafting of Diazotated Anthraquinone as a Means of Forming Thick Conducting Organic Films

Thick conductive layers containing anthraquinone moieties are covalently immobilized on gold using redox grafting of the diazonium salt of anthraquinone (i.e., 9,10-dioxo-9,10-dihydroanthracene-1-diazonium tetrafluoroborate). This grafting procedure is based on using consecutive voltammetric sweeping and through this exploiting fast electron transfer reactions that are mediated by the anthraquinone redox moieties in the film. The fast film growth, which is followed by infrared reflection absorption spectroscopy, atomic force microscopy, X-ray photoelectron spectroscopy, ellipsometry, and coverage calculation, results in a mushroom-like structure. In addition to varying the number of sweeps, layer thickness control can easily be exerted through appropriate choice of the switching potential and sweep rate. It is shown that the grafting of the diazonium salt is essentially a diffusion-controlled process but also that desorption of physisorbed material during the sweeping process is essentially for avoiding blocking of the film due to clogging of the electrolyte channels in the film. In general, sweep rates higher than 0.5 V s^–1 are required if thick, porous, and conducting films should be formed

Improved Safety during Transfer of Pyrophoric <i>tert</i>-Butyllithium from Flasks with Protective Seals

A simple setup has been devised to facilitate safer transfer of air-sensitive and pyrophoric reagents from Sure/Seal bottles in a fume hood setting. The setup is composed of three parts; a sealed transfer vial, a custom bottle cap for transfer vial alignment, and a metal clip. All of the needed parts are constructed from standard laboratory equipment and by 3D printing. Titration of <i>tert</i>-butyllithium was used as an example of safe transfer of a highly pyrophoric reagent, and an instructional video has been prepared

Anthraquinone Oligomers as Anode-Active Material in Rechargeable Nickel/Oligomer Batteries with Aqueous Electrolyte

This work is an initial investigation of the possible use of redox-active anthraquinone as anode material in combination with Ni­(OH)₂ in a secondary battery with aqueous KOH electrolyte. Three different anode materials are investigated: an anthraquinone monomer and two different anthraquinone based oligomers. All batteries are rechargeable, and almost 100% of the theoretical capacity can be accessed in the first cycle, after which significant capacity loss occurs. The capacity loss is attributed mainly to swelling of the electrodes and solubility of anthraquinones in their charged (reduced) state because reduced anthraquinone is deprotonated and ionized in alkaline solutions. Nonetheless, batteries based on one of the oligomerized anthraquinones (oligo­[benzene-1,4-dithiol-<i>alt</i>-(1,5- dichloroanthraquinone)] anode) show the best performance and retain almost 50% of the discharge capacity after 100 cycles. The better performance is attributed to the reduced solubility caused by the oligomerization. It is anticipated that measures to decrease the solubility further could lead to much improved capacity retention

Tailoring Membrane Nanostructure and Charge Density for High Electrokinetic Energy Conversion Efficiency

The electrokinetic energy conversion (EKEC) of hydraulic work directly into electrical energy has been investigated in charged polymeric membranes with different pore charge densities and characteristic diameters of the nanoporous network. The membranes were synthesized from blends of nitrocellulose and sulfonated polystyrene (SPS) and were comprehensively characterized with respect to structure, composition, and transport properties. It is shown that the SPS can be used as a sacrificial pore generation medium to tune the pore size and membrane porosity, which in turn highly affects the transport properties of the membranes. Furthermore, it is shown that very high EKEC efficiencies (>35%) are encountered in a rather narrow window of the properties of the nanoporous membrane network, that is, with pore diameters of <i>ca</i>. 10 nm and pore charge densities of 4.6 × 10² to 1.5 × 10³ mol SO₃^– m^–3 for dilute solutions (0.03 M LiCl). The high absolute value of the efficiency combined with the determination of the optimal membrane morphology makes membrane-based EKEC devices a step closer to practical applications and high-performance membrane design less empirical

Electrochemical Polymerization of Allylamine Copolymers

We describe for the first time the electro-oxidative synthesis and passivating properties of surface films of poly­(allylamine) and copolymers of allylamine and diallylamine. Cyclic voltammetry and impedance spectra show that the films exhibit high charge-transfer resistance and that the addition of diallylamine causes improvements in the compactness and stability toward swelling of the films when compared to both allylamine and diallyamine, leading to coatings with high charge-transfer resistance up to 70 MΩ. We also show that removing oxygen before the polymerization further improves the films’ passivating properties

Synthesis of β‑Cyclodextrin Diazonium Salts and Electrochemical Immobilization onto Glassy Carbon and Gold Surfaces

This study shows that diazotized β-cyclodextrin (β-CD) can be produced, isolated, and immobilized onto glassy carbon and gold surfaces. 4-(1,2,3-Triazol-4-yl)­benzenediazonium-β-CD tetrafluoroborate (pDz-β-CD) and 3-(1,2,3-triazol-4-yl)­benzenediazonium-β-CD tetrafluoroborate (mDz-β-CD) were successfully prepared by Cu^(I)-catalyzed azide alkyne coupling (CuAAC) of 6-monodeoxy-6-monoazido-β-cyclodextrin (N₃-β-CD) and 4-ethynylaniline and 3-ethynylaniline, respectively, followed by diazotization. The products were isolated and stored successfully for several months at −18 °C. The intermediates and products were verified by Attenuated Total Reflectance Fourier Transform Infrared, Nuclear Magnetic Resonance, and Heteronuclear Single Quantum Coherence.pDz-β-CD and mDz-β-CD were immobilized onto glassy carbon and gold surfaces facilitated by electrochemical reduction of the diazonium group. The thus generated aryl radical reacted with the surface. The modified gold surfaces were investigated by Polarization Modulation Infrared Reflection Absorption Spectroscopy and cyclic voltammetry employing the redox probe K₃Fe­(CN)₆ to analyze the extent of blocking of the surfaces. Finally, the availability of the cavity of surface-immobilized β-CD was shown by complexation of ferrocene followed by cyclic voltametric analysis