Journal ArticleDOI
Ligand substitution kinetics of iron(III) in aprotic solvents
JT Carr,PA Treloan +1 more
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TLDR
In this paper, the authors studied the complexation reactions of NCS- and Br- with iron(III) in N,N-dimethyl-formamide, and the temperature activation parameters determined.Abstract:
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±5 and 69±31, mol-1 s-1, the activation enthalpies are 48+±3 and 74±4 kJ mol-1, and the activation entropies are -45±8 and 40±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±31. Mol-1 s-1, the activation enthalpy is 42±3 kJ mol-1, and the activation entropy is -70±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.read more
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Book ChapterDOI
Substitution Reactions of Labile Metal Complexes
TL;DR: In this paper, Cox and Schneider set the framework for complexation of very labile ions by simple ligands and then constrasted this with the special features to be considered for macrocyclic ligands.