Formation and kinetics of decomposition of monoaquobis(ethylenediamine)(pyridylmethyl)chromium(III) complexes
Abstract
Monoaquobis(ethylenediamine)(pyridylmethyl)chromium(III) complexes, 2-NC5H4CH2Cr(en)2(H2O)2+ and 3-NC5H4CH2Cr(en)2(H2O)2+, are prepared by the reduction of the corresponding picolyl chlorides by the CrII(en)22+ ion. The decomposition of these ions is studied in 0·01–1·0M-perchloric acid and in acetate buffers of pH 1–7. Spectral changes show that these complexes undergo aquation before carbon–chromium bond cleavage. Product studies as well as kinetic data and activation parameters obtained indicate that the 2- and 3-ions decompose via the penta-aquo-derivative, 2-NC5H4CH2Cr(H2O)52+, and the trisaquo-derivative, 3-NC5H4CH2Cr(en)(H2O)32+ respectively. Acetate-ion catalysis is also observed for the decomposition of these ions.