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Peroxide Coordination of Tellurium in Aqueous Solutions
Author(s) -
Mikhaylov Alexey A.,
Medvedev Alexander G.,
Churakov Andrei V.,
Grishanov Dmitry A.,
Prikhodchenko Petr V.,
Lev Ovadia
Publication year - 2016
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201503614
Subject(s) - aqueous solution , tellurate , chemistry , tellurium , hydrogen peroxide , peroxide , crystal structure , inorganic chemistry , raman spectroscopy , ammonium , crystallography , ion , organic chemistry , physics , optics
Tellurium–peroxo complexes in aqueous solutions have never been reported. In this work, ammonium peroxotellurates (NH 4 ) 4 Te 2 (μ‐OO) 2 (μ‐O)O 4 (OH) 2 ( 1 ) and (NH 4 ) 5 Te 2 (μ‐OO) 2 (μ‐O)O 5 (OH)⋅1.28 H 2 O⋅0.72 H 2 O 2 ( 2 ) were isolated from 5 % hydrogen peroxide aqueous solutions of ammonium tellurate and characterized by single‐crystal and powder X‐ray diffraction analysis, by Raman spectroscopy and thermal analysis. The crystal structure of 1 comprises ammonium cations and a symmetric binuclear peroxotellurate anion [Te 2 (μ‐OO) 2 (μ‐O)O 4 (OH) 2 ] 4− . The structure of 2 consists of an unsymmetrical [Te 2 (μ‐OO) 2 (μ‐O)O 5 (OH)] 5− anion, ammonium cations, hydrogen peroxide, and water. Peroxotellurate anions in both 1 and 2 contain a binuclear Te 2 (μ‐OO) 2 (μ‐O) fragment with one μ‐oxo‐ and two μ‐peroxo bridging groups. 125 Te NMR spectroscopic analysis shows that the peroxo bridged bitellurate anions are the dominant species in solution, with 3–40 %wt H 2 O 2 and for pH values above 9. DFT calculations of the peroxotellurate anion confirm its higher thermodynamic stability compared with those of the oxotellurate analogues. This is the first direct evidence for tellurium–peroxide coordination in any aqueous system and the first report of inorganic tellurium–peroxo complexes. General features common to all reported p‐block element peroxides could be discerned by the characterization of aqueous and crystalline peroxotellurates.