1. Air-stable aryl derivatives of pentafluoroorthotellurate
Daniel Wegener, Kurt F Hoffmann, Alberto Pérez-Bitrián, Ilayda Bayindir, Amiera N Hadi, Anja Wiesner, Sebastian Riedel Chem Commun (Camb). 2022 Aug 25;58(69):9694-9697. doi: 10.1039/d2cc03936b.
We report on two different sets of air-stable derivatives of pentafluoroorthotellurate containing fluorinated and non-fluorinated aryl groups. The acid cis-PhTeF4OH was obtained in gram scale and further transformed to Ag[cis-PhTeF4O], which was used as a cis-PhTeF4O transfer reagent to obtain [PPh4][cis-PhTeF4O]. Furthermore, the synthesis of trans-(C6F5)2TeF3OH was achieved by a selective hydrolysis of trans-(C6F5)2TeF4 in the presence of KF and subsequent protonation by aHF. Quantum-chemical calculations show a higher acidity and robustness against fluoride abstraction for trans-(C6F5)2TeF3OH compared to cis-PhTeF4OH.
2. Atmospheric Sulfuric Acid Dimer Formation in a Polluted Environment
Ke Yin, Shixin Mai, Jun Zhao Int J Environ Res Public Health. 2022 Jun 3;19(11):6848. doi: 10.3390/ijerph19116848.
New particle formation (NPF) contributes significantly to atmospheric particle number concentrations and cloud condensation nuclei (CCN). In sulfur-rich environments, field measurements have shown that sulfuric acid dimer formation is likely the critical step in NPF. We investigated the dimer formation process based upon the measured sulfuric acid monomer and dimer concentrations, along with previously reported amine concentrations in a sulfur-rich atmosphere (Atlanta, USA). The average sulfuric acid concentration was in the range of 1.7 × 107-1.4 × 108 cm-3 and the corresponding neutral dimer concentrations were 4.1 × 105-5.0 × 106 cm-3 and 2.6 × 105-2.7 × 106 cm-3 after sub-collision and collision ion-induced clustering (IIC) corrections, respectively. Two previously proposed acid-base mechanisms (namely AA and AB) were employed to respectively estimate the evaporation rates of the dimers and the acid-amine complexes. The results show evaporation rates of 0.1-1.3 s-1 for the dimers based on the simultaneously measured average concentrations of the total amines, much higher than those (1.2-13.1 s-1) for the acid-amine complexes. This indicates that the mechanism for dimer formation is likely AA through the formation of more volatile dimers in the initial step of the cluster formation.
3. BiCl3 catalyzed synthesis of 2-amino-1,4-naphthoquinones and 1,4-naphthoquinon-2-sulfides and one-pot sequential amine-arylation of 1,4-naphthoquinone
Mayurakhi Bhuyan, Gakul Baishya Org Biomol Chem. 2022 Nov 30;20(46):9172-9183. doi: 10.1039/d2ob01792j.
Using the Lewis acid catalyst BiCl3, a new method for the synthesis of 2-amino-1,4-naphthoquinones and 1,4-naphthoquinon-2-sulfides from 1,4-naphthoquinone has been devised. This method has a broad substrate scope and product extraction is easy. It is low-cost, requires mild and sustainable reaction conditions and results in superior product yields. Additionally, this study presents the first technique for one-pot sequential amine-arylation with amines and arylhydrazines/K2S2O8 to produce arylated 2-amino-1,4-naphthoquinones directly from 1,4-naphthoquinone. This operationally straightforward generation of aryl radicals from arylhydrazines that undergo a free radical coupling reaction is well demonstrated by radical trapping control experiments.
