Steric course and kinetics of aquation of some haloaquotetraamminechromium(III) complexes

Abstract

The aquation stoioheiometry of cis. and trans-Cr(NH₃)_,(OH₂)Br²⁺ and cis- and trans-Cr(NH₃)₄(OH₂)I²⁺ ions when either spontaneous, Hg²⁺ promoted, or carried out via the hydroxo forms generated in basic solution has been examined. The two latter treatments have been conducted on cis-Cr(NH₃)₄(OH₂)C1²⁺ ion. Spectrophotometric methods show all lose halide with retention of configuration. The rates of aquation in acid media of the Cr(NH₃)₄(OH₂)Br²⁺ and Cr(NH₃)_,(OH₂)I²⁺ ions have been investigated and comparisons are made with related tetraammine and bis(ethylenediamine) oomplexes. Evidence has accumulated to show almost complete stereoretentivity in the aquation reactions of chromium(111) amine complexes.