In Situ Synthesis and Applications for Polyinterhalides Based on BrCl

The use of neat BrCl in organic and inorganic chemistry is limited due to its gaseous aggregate state and especially its decomposition into Cl2 and Br2 . The stabilization of BrCl in form of reactive ionic liquids via a novel in situ synthesis route shifts this equilibrium drastically to the BrCl side, which leads to safer and easier-to-handle interhalogenation reagents. Furthermore, the crystalline derivatives of the hitherto unknown [Cl(BrCl)2 ]- and [Cl(BrCl)4 ]- anions were synthesized and characterized by single-crystal X-ray diffraction (XRD), Raman and IR spectroscopy, as well as quantum chemical calculations.

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

Herein, we report the synthesis and characterization of a variety of novel poly(hydrogen halide) halogenates (-I). The bifluoride ion, which is known to have the highest hydrogen bond energy of ≈160 kJ mol-1 , is the most famous among many examples of [X(HX)n ]- 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 ]- ). In this work we present the synthesis of anions of the type [X(HY)n ]- (X=Br, I, ClO4 ; Y=Cl, Br, CN) stabilized by the [PPh4 ]+ and [PPN]+ cation. The obtained compounds have been characterized by single-crystal X-ray diffraction, Raman spectroscopy and quantum-chemical calculations. In addition, the behavior of halide ions in hydrogen fluoride was investigated by using experimental and quantum-chemical methods in order to gain knowledge on the acidity of hydrogen halides in HF.

Salts of HCN-Cyanide Aggregates: [CN(HCN)2 ]- and [CN(HCN)3 ]. Angew Chem Int Ed Engl 2020;59:10508-10513. [PMID: 32027458 PMCID: PMC7317722 DOI: 10.1002/anie.201915206]

Although pure hydrogen cyanide can spontaneously polymerize or even explode, when initiated by small amounts of bases (e.g. CN^- ), the reaction of liquid HCN with [WCC]CN (WCC=weakly coordinating cation=Ph₄ P, Ph₃ PNPPh₃ =PNP) was investigated. Depending on the cation, it was possible to extract salts containing the formal dihydrogen tricyanide [CN(HCN)₂ ]^- and trihydrogen tetracyanide ions [CN(HCN)₃ ]^- from liquid HCN when a fast crystallization was carried out at low temperatures. X-ray structure elucidation revealed hydrogen-bridged linear [CN(HCN)₂ ]^- and Y-shaped [CN(HCN)₃ ]^- molecular ions in the crystal. Both anions can be considered members of highly labile cyanide-HCN solvates of the type [CN(HCN)_n ]^- (n=1, 2, 3 …) as well as formal polypseudohalide ions.