Synthesis and Characterization of Poly(hydrogen halide) Halogenates (–I)

Abstract

Herein, we report the synthesis and characterization of av ariety of novel poly(hydrogen halide) halogenates (ÀI). The bifluoride ion, which is knownt oh avet he highest hydrogen bond energy of % 160 kJ mol À1 ,i st he most famousa mong many exampleso f[ X(HX) n ] À anions (X = F, Cl) known in the literature. In contrast, little is known about poly(hydrogen halide) halogenates containing two different halogens, ([X(HY) n ] À). In this work we presentt he synthesis of anions of the type [X(HY) n ] À (X = Br,I ,C lO 4 ;Y= Cl,B r, CN) stabilized by the [PPh 4 ] + and [PPN] + cation. The obtained compounds have been characterizedb ys ingle-crystal X-ray diffraction, Raman spectroscopy and quantum-chemical calculations.I na ddition,t he behavior of halidei ons in hydrogen fluoride wasi nvestigated by using experimental and quantum-chemical methodsi no rder to gain knowledge on the acidity of hydrogen halides in HF. Scheme1.Synthetic routes for the synthesis of poly(hydrogen halide) halogenates (ÀI).

Bichloride-based ionic liquids for the merged storage, processing, and electrolysis of hydrogen chloride

“…This ionic liquid can directly be used as a chlorination reagent for the synthesis of base chemicals such as phosgene ( 29 ). On the basis of these works and our previous investigations of poly(hydrogen halide) halogenates ( 30 ), we anticipated that ammonium chloride salts [NR 3 Me]Cl could be a scalable platform for the safe and reversible storage of hydrogen chloride while serving as an easy-to-handle hydrochlorination reagent and as a feedstock for the electrochemical generation of hydrogen and chlorine.…”

“…To examine this possibility, we treated the readily available ammonium chlorides [NEt 3 Me]Cl, [NEt 2 Me 2 ]Cl, [NPr 3 Me]Cl, and [NBu 3 Me]Cl with gaseous hydrogen chloride ( Fig. 1C ) ( 30 , 31 ). To elucidate the molecular structure of the formed ionic liquids, we prepared colorless crystals suitable for single-crystal x-ray diffraction by adding CH 2 Cl 2 to the ionic liquid, before slowly cooling to −80°C (see figs.…”

“…Thus, the donation of electron density from the lone pair of the chloride ion into the σ* orbital of the H-Cl bond results in a 3c-4e bond (see fig. S18) ( 30 , 32 ).…”