Rate constants for the reduction of monohalogenochromium(III) complexes with europium(II)
Abstract
The reactions of europium(II) with monohalogenochromium(III) complexes, EuII+ CrX2+→ EuIII+ CrII+ X–, have been studied in aqueous perchloric acid solutions, µ= 1·0M. In all but the reaction of monofluorochromium(III) allowances were made for the uncatalysed and chromium(II)-catalysed aquation of CrX2+. Contributions from these reactions are of decreasing importance in going from Crl2+ to CrF2+, and can be ignored for the latter. At 25° rate constants are Crl2+(4·1 × 10–2 sec.–1) > CrBr2+(3·4 × 10–3 sec.–1) > CrCl2+(1·4 × 10–3 sec.–1) > CrF2+(6·0 × 10–4 sec.–1). Although there is no proof, the reactions are discussed in terms of an inner-sphere mechanism. The effect which bridging halide ions have on electron-transfer reactions is considered.
Please wait while we load your content...
