38819-71-5Relevant academic research and scientific papers
Protonation and aquation of chromium(III)/ethanolamine complexes in aqueous solution
Kolosci, Lois,Schug, Kenneth
, p. 3053 - 3056 (2008/10/08)
Several Cr(III) complexes with amino alcohols have been prepared, and the solution chemistry of the tris(2-aminoethanol) complex has been studied in detail. Addition of excess strong acid to solutions containing Cr(Eta)30 (Eta = bidentate aminoalkoxy) results in the following sequence of reactions: stage I, instantaneous protonation to produce bidentate Cr(EtaH)33+ (EtaH = 2-aminoethanol); stage II, rapid (complete in ～10 min at 20°C) conversion to monodentate Cr(EtaH)3(OH2)33+ by ring opening at the alcohol function; stage III, slower stepwise aquation of the N-bonded ethanolamine to produce Cr(OH2)63+. The first-order rate constants in stage III (25°C, μ = 0.10) are k3→2 = 2.3 × 10-4 s-1, k2→1 = 1.7 × 10-5 s-1, and k1→0 = 6.4 × 10-7 s-1. Aquation rates in stages II and III (k1→0) are much faster than normal for Cr(III) complexes but have a precedent in the Cr(III)/ethylene glycol system.
