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Cu[B 2 (SO 4 ) 4 ] and Cu[B(SO 4 ) 2 (HSO 4 )]—Two Silicate Analogue Borosulfates Differing in their Dimensionality: A Comparative Study of Stability and Acidity
Author(s) -
Bruns Jörn,
Podewitz Maren,
Liedl Klaus R.,
Janka Oliver,
Pöttgen Rainer,
Huppertz Hubert
Publication year - 2018
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.201803395
Subject(s) - crystallography , chemistry , copper , ion , silicate , stereochemistry , organic chemistry
Borosulfates are an ever‐expanding class of compounds and the extent of their properties is still elusive. Herein, the first two copper borosulfates Cu[B 2 (SO 4 ) 4 ] and Cu[B(SO 4 ) 2 (HSO 4 )] are presented, which are structurally related but show different dimensionalities in their substructure: While Cu[B 2 (SO 4 ) 4 ] reveals an anionic chain,∞ 1 [B(SO 4 ) 4/2 ] − , with both a twisted and a unique chair conformation of the B(SO 4 ) 2 B subunits, Cu[B(SO 4 ) 2 (HSO 4 )] reveals isolated [B 2 (SO 4 ) 4 (HSO 4 ) 2 ] 4− anions showing exclusively a twisted conformation. The complex anion can figuratively be obtained as a cut‐out from the anionic chain by protons. Comparative DFT calculations based on magnetochemical measurements complement the experimental studies. Calculation of the p K a values of the two conformers of the [B 2 (SO 4 ) 4 (HSO 4 ) 2 ] 4− anion revealed them to be more similar to silicic than to sulfuric acid, highlighting the close relationship to silicates.