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Do Perchlorate and Triflate Anions Bind to the Uranyl Cation in an Acidic Aqueous Medium? A Combined EXAFS and Quantum Mechanical Investigation
Author(s) -
Sémon Laurent,
Boehme Christian,
Billard Isabelle,
Hennig Christoph,
Lützenkirchen Klaus,
Reich Tobias,
Roßberg André,
Rossini Isabelle,
Wipff Georges
Publication year - 2001
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/1439-7641(20011015)2:10<591::aid-cphc591>3.0.co;2-b
Subject(s) - uranyl , chemistry , trifluoromethanesulfonate , perchlorate , inorganic chemistry , aqueous solution , extended x ray absorption fine structure , perchloric acid , aqueous medium , ion , catalysis , organic chemistry , absorption spectroscopy , physics , quantum mechanics
Structural properties of uranyl cations in acidic aqueous perchlorate and triflate solutions were investigated using uranium L III ‐edge extended X‐ray absorption fine‐structure spectroscopy (EXAFS) in conjunction with quantum mechanical calculations of gas‐phase model complexes. EXAFS spectra were measured in aqueous solutions of up to 10 M triflic and 11.5 M perchloric acid, as well as mixtures of perchloric acid and sodium perchlorate. In no case is the perchlorate anion coordinated to UO 2 2+ . The number of equatorial water molecules bound to UO 2 2+ is always about five. In the case of the 10 M CF 3 SO 3 H solution, an inner‐sphere complexation of the triflate is observed with a U−S radial distance of 3.62 Å. These results are in qualitative agreement with quantum mechanical calculations of model uranyl complexes, according to which the interaction energies of anions follow the order perchlorate