
%0 Journal Article
%A Carr, JT 
%A Treloan, PA 
%T Ligand substitution kinetics of iron(III) in aprotic solvents
%J Australian Journal of Chemistry
%D 1983/05/01
%V 36
%N 5
%P 843-854
%K 
%R https://doi.org/10.1071/CH9830843
%U https://www.publish.csiro.au/paper/CH9830843 
%X The complexation reactions of NCS- and Br- with iron(III) have been studied in N,N-dimethyl-formamide, and the temperature activation parameters determined. The observed forward rate constants are 114&#177;5 and 69&#177;31, mol-1 s-1, the activation enthalpies are 48+&#177;3 and 74&#177;4 kJ mol-1, and the activation entropies are -45&#177;8 and 40&#177;10 J K-1 mol-1, respectively, at 298 K and 0.5 M ionic strength. The complexation reactions of NCS- with iron(III) in dimethyl sulfoxide have been studied at ionic strengths of 0.1, 0.3 and 0.5 M, and over a range of temperatures. The observed forward rate constant is 55&#177;31. Mol-1 s-1, the activation enthalpy is 42&#177;3 kJ mol-1, and the activation entropy is -70&#177;30 J K-1 mol-1 at 298 K and 0.5 M ionic strength. It is proposed that the substitution reactions of iron(111) in the aprotic solvents N,N-dimethyl- formamide and dimethyl sulfoxide proceed through an associative interchange (Ia) mechanism. 
