Azolylborates for Electrochemical Double Layer Capacitor Electrolytes

Asymmetric tetraalkylammonium salts of azolylborates were synthesized and studied with respect to their suitability as supporting electrolytes in electrochemical double layer capacitors. In contrast to current conducting salts used in this device, azolylborates exhibit an excellent stability towards thermal load and moisture. In addition to good conductivity and stability towards cathodic reduction we found certain limitations when more positive potentials were applie

Highly Sensitive Detection of Naphthalene in Solvent Vapor Using a Functionalized PBG Refractive Index Sensor

We report an optical refractive index sensor system based on a planar Bragg grating which is functionalized by substituted γ-cyclodextrin to determine low concentrations of naphthalene in solvent vapor. The sensor system exhibits a quasi-instantaneous shift of the Bragg wavelength and is therefore capable for online detection. The overall shift of the Bragg wavelength reveals a linear relationship to the analyte concentration with a gradient of 12.5 ± 1.5 pm/ppm. Due to the spectral resolution and repeatability of the interrogation system, this corresponds to acquisition steps of 80 ppb. Taking into account the experimentally detected signal noise a minimum detection limit of 0.48 ± 0.05 ppm is deduced

Efficient electroorganic synthesis of 2,3,6,7,10,11-hexahydroxytriphenylene derivatives

2,3,6,7,10,11-Hexahydroxytriphenylene of good quality and purity can be obtained via anodic treatment of catechol ketals and subsequent acidic hydrolysis. The electrolysis is conducted in propylene carbonate circumventing toxic and expensive acetonitrile. The protocol is simple to perform and superior to other chemical or electrochemical methods. The key of the method is based on the low solubility of the anodically trimerized product. The shift of potentials is supported by cyclic voltammetry studies

Electrochemical Bromofunctionalization of Alkenes and Alkynes—To Sustainability and Beyond

The electrochemical generation of highly reactive and hazardous bromine under controlled conditions as well as the reduction of surplus oxidizers and reagent waste has placed electrochemical synthesis in a highlighted position. In particular, the electrochemical dibromination and bromofunctionalization of alkenes and alkynes have received significant attention, as the forming of synthetically important derivatives can be generated from bench-stable and safe bromide sources under “green” conditions. Readily available and non-corrosive bromide salts have been utilized with a dual role as both a reagent and supporting electrolyte. However, this trend seems to change with the preparation of organobromine species. In this review, the electrochemical dibromination and bromofunctionalization of alkenes and alkynes was addressed in terms of their bromine sources and sustainability

Electrochemical Bromofunctionalization of Alkenes and Alkynes—To Sustainability and Beyond

The electrochemical generation of highly reactive and hazardous bromine under controlled conditions as well as the reduction of surplus oxidizers and reagent waste has placed electrochemical synthesis in a highlighted position. In particular, the electrochemical dibromination and bromofunctionalization of alkenes and alkynes have received significant attention, as the forming of synthetically important derivatives can be generated from bench-stable and safe bromide sources under “green” conditions. Readily available and non-corrosive bromide salts have been utilized with a dual role as both a reagent and supporting electrolyte. However, this trend seems to change with the preparation of organobromine species. In this review, the electrochemical dibromination and bromofunctionalization of alkenes and alkynes was addressed in terms of their bromine sources and sustainability

Crystal structure of ethyl 2-(diethoxyphosphoryl)-2-(2,3,4-trimethoxyphenyl)acetate

The title compound, C17H27O8P, was prepared by Michaelis–Arbuzov reaction of ethyl 2-bromo-2-(2,3,4-trimethoxyphenyl)acetate and triethyl phosphite. Such compounds rarely crystallize, but single crystals were recovered after the initial oil was left for approximately 10 years. The bond angle of the sp3-hybridized C atom connecting the benzene derivative with the phospho unit is widened marginally [112.5 (2)°]. The terminal P—O bond length of 1.464 (2) Å clearly indicates a double bond, whereas the two O atoms of the ethoxy groups connected to the phosphorous atom have bond lengths of 1.580 (2) Å and 1.581 (3) Å. The three methoxy groups emerge out of the benzene-ring plane due to steric hindrance [C—C—O—C torsion angles = −179.9 (3)°, −52.9 (4)° and 115.3 (4)°]. In the crystal, inversion dimers linked by pairs of C—H...O=P hydrogen bonds generate R22(14) loops. The chosen crystal was modelled as a non-merohedral twin

Synthesis of Highly Functionalized 9,10-Phenanthrenequinones by Oxidative Coupling Using MoCl₅

The strong oxidative power of molybdenum pentachloride gives rise to an efficient oxidative C–C bond formation of benzil derivatives to the corresponding 9,10-phenanthrenequinones. A highly complementary method to previous approaches was developed. The required derivatives are accessible in a modular fashion and in excellent yields. By this approach the orchid-derived natural product cypripediquinone A was synthesized for the first time