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Stability Constants and Decay of Aqua‐Copper(III) – A Study by Pulse Radiolysis with Conductometric and Optical Detection
Author(s) -
Ulanski Piotr,
von Sonntag Clemens
Publication year - 2000
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(200006)2000:6<1211::aid-ejic1211>3.0.co;2-1
Subject(s) - chemistry , radiolysis , radical , copper , aqueous solution , inorganic chemistry , conductometry , ion , qualitative inorganic analysis , stability constants of complexes , conductance , nuclear chemistry , organic chemistry , mathematics , combinatorics
Hydroxyl radicals were generated radiolytically in N 2 O‐saturated aqueous solutions and reacted with Cu 2+ aqions. Pulse radiolysis with conductometric detection showed that the aqua‐Cu III species thus formed ( k = 3.2 × 10 8 dm 3 mol –1 s –1 ) is uncharged at pH 5, i.e. [Cu(OH) 3 ] aq , and from the changes in conductance as a function of pH it has been calculated that Cu(OH) must have a p K value of 4.8 and Cu(OH) 2+ aqa value of 3.7. At pH 2.5 there is no strong evidence for the presence of Cu 3+ aq . Aqua‐Cu(OH) 3 decays bimolecularly to give Cu 2+ aqand H 2 O 2 . Cu(OH) 2+ aq[and possibly also Cu(OH)] are in equilibrium with Cu 2+ aqand OH radicals [ K (Cu(OH) 2+ aq ) ≈ 3.7 × 10 4 dm 3 mol –1 ]. Rapid electron transfer occurs from Cu + aqto [Cu(OH) 3 ] aq ( k = 3.5 × 10 9 dm 3 mol –1 s –1 ).