A Direct One-Step Preparation of Triarylverdazylium Salts from the Corresponding Triarylformazans
作者:Alan R. Katritzky、Sergei A. Belyakov
DOI:10.1055/s-1997-1516
日期:1997.1
6-(4-Substituted-phenyl)-2,4-diphenylverdazylium salts 2 (8 examples, 55-93%) were prepared by the reaction of 3-(4-substituted-phenyl)-1,5-diphenylformazans 1 with formaldehyde and different organic and inorganic acids in a two-phase chloroform/water medium by brief and gentle heating. Self-phase-transfer catalysis is apparently involved. Subsequent reductions of the salts 2 with excess ascorbic acid in the two-phase system give the corresponding verdazyl radicals, while in methanol the reduction proceeds to form leuco-verdazyls.
A sol-gel coating composition comprising a hydrolysed organosilane, an organometallic precursor and a corrosion inhibitor, wherein the corrosion inhibitor is a chelator for the organometallic precursor. The corrosion inhibitor and the organometallic precursor may form a nanoparticulate complex. The coating composition may comprise one or more additive selected from: an antimicrobial additive, a hardener, a water repelling additive, a dye, a scratch resistant additive and a flexibility enhancing additive. A process for preparing a sol gel coating composition is also described, the process comprising the steps of: hydrolysing an organosilane in the presence of a catalyst; chelating an organometallic precursor; mixing the hydrolysed silane and the chelated organometallic precursor; and hydrolysing the organosilane-organometallic precursor mixture.
Unraveling the Electrochemistry of Verdazyl Species in Acidic Electrolytes for the Application in Redox Flow Batteries
作者:Simon Kunz、Mari Janse van Rensburg、Dennis S. Pietruschka、Andreas J. Achazi、Dominik Emmel、Felix Kerner、Doreen Mollenhauer、Hermann A. Wegner、Daniel Schröder
DOI:10.1021/acs.chemmater.2c02279
日期:2022.12.13
Verdazylradicals are a promising class of materials for the potential application in organic redox flow batteries. Although studies on the redox behavior of verdazylradicals in organic solvents exist, only the disproportionation in aqueous acidic electrolytes is known. Herein, we address this knowledge gap by analyzing the verdazyl species after disproportionation with a series of electrochemical
We report herein an organic chargetransfer cocrystal complex, consisting of a stable radical TPVr and an electron acceptor TCNQF4, as a rare sort of all-organic-based magnetic bistable materials with a thermally activated magnetic hysteresis loop over the temperature range from 170 to 260 K. Detailed X-ray crystallographic studies and theoretical calculations revealed that while a π-associated radical
Bipolar Verdazyl Radicals for Symmetrical Batteries: Properties and Stability in All States of Charge
作者:Jelte S. Steen、Folkert de Vries、Johan Hjelm、Edwin Otten
DOI:10.1002/cphc.202200779
日期:2023.2.14
Bipolar organic radicals are promising materials for symmetrical redox-flow batteries. The authors investigate the chemical stability issues that contribute to capacity fade. It is shown that rather than the energized (charged) states, the capacity fade is determined by bimolecular decomposition of the neutral radical.