Premium
Protonation versus Oxonium Salt Formation: Basicity and Stability Tuning of Cyanoborate Anions
Author(s) -
Kerpen Christoph,
Sprenger Jan A. P.,
Herkert Lorena,
Schäfer Marius,
Bischoff Lisa A.,
Zeides Pierre,
Grüne Matthias,
Bertermann Rüdiger,
Brede Franziska A.,
MüllerBuschbaum Klaus,
Ignat'ev Nikolai V.,
Finze Maik
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201611901
Subject(s) - oxonium ion , protonation , chemistry , anhydrous , salt (chemistry) , crystallography , ionic bonding , ion , aqueous solution , hydrogen bond , inorganic chemistry , medicinal chemistry , molecule , organic chemistry
Anhydrous H[BH 2 (CN) 2 ] crystallizes from acidic aqueous solutions of the dicyanodihydridoborate anion. The formation of H[BH 2 (CN) 2 ] is surprising as the protonation of nitriles requires strongly acidic and anhydrous conditions but it can be rationalized based on theoretical data. In contrast, [BX(CN) 3 ] − (X=H, F) gives the expected oxonium salts (H 3 O)[BX(CN) 3 ] while (H 3 O)[BF 2 (CN) 2 ]/H[BF 2 (CN) 2 ] is unstable. H[BH 2 (CN) 2 ] forms chains via N−H⋅⋅⋅N bonds in the solid state and melts at 54 °C. Solutions of H[BH 2 (CN) 2 ] in the room‐temperature ionic liquid [EMIm][BH 2 (CN) 2 ] contain the [(NC)H 2 BCN−H⋅⋅⋅NCBH 2 (CN)] − anion and are unusually stable, which enabled the study of selected spectroscopic and physical properties. [(NC)H 2 BCN−H⋅⋅⋅NCBH 2 (CN)] − slowly gives H 2 and [(NC)H 2 BCN−BH(CN) 2 ] − . The latter compound is a source of the free Lewis acid BH(CN) 2 , as shown by the generation of [BHF(CN) 2 ] − and BH(CN) 2 ⋅py.