Spontaneous aquation reactions of a promising tumor inhibitor trans-imidazolium-tetrachlorobis(imidazole)ruthenium(III), trans-HIm[RuCl4(Im)2]
1995; Elsevier BV; Volume: 233; Issue: 1-2 Linguagem: Inglês
10.1016/0020-1693(94)04447-4
ISSN1873-3255
AutoresJanusz Chatłas, Rudi van Eldik, Bernhard K. Keppler,
Tópico(s)Magnetism in coordination complexes
ResumoThe spontaneous aquation reaction of trans-RuCl4(Im)2−, Im = imidazole, was studied as a function of pH, chloride concentration, imidazole buffer and temperature, using spectrophotometric and chromatographic techniques. The selected pH and chloride concentration control the degree of aquation observed. In all cases evidence for the formation of RuCl3(Im)2H2O was found, which can undergo deprotonation and/or subsequent aquation depending on the pH and free chloride concentration in solution. No evidence for aquation of the imidazole ligand was found. The formation of RuCl3(Im)2H2O is characterized by a rate constant of 1.5 × 10−5 s−1 at 25 °D, ΔH# = 117 ± 7 kJ mol−1 and ΔS# = +55 ± 23 J K−1 mol−1. The results are discussed in reference to the tumor inhibiting properties of the complex.
Referência(s)