ISSN print edition: 0366-6352
ISSN electronic edition: 1336-9075
Registr. No.: MK SR 9/7
Kinetics of chloride substitution in [Pt(bpma)Cl]+ and [Pt(gly-met-S,N,N)Cl] complexes by thiourea, nitrites, and iodides
Adrian Topolski and Živadin Bugarčić
Faculty of Chemistry, Nicolaus Copernicus University, Gagarina 7, 87-100, Toruń, Poland
Abstract: Substitution of chloride in [PtCl(bpma)]+ and [PtCl(gly-met-S,N,N)], where bpma is bis(2-pyridylmethyl)amine and gly-met-S,N,N is glycyl-l-methionine, was studied as a function of the entering nucleophile concentration and temperature. Reactions between the platinum(II) complexes and thiourea (TU), iodides (I−), and nitrites(III) (NO 2 −) were carried out in aqueous solutions using conventional UV-VIS spectrophotometry. Suitable ionic conditions were reached by an addition of 0.1 M NaClO4 and 0.01 M NaCl (to suppress hydrolysis). The second-order rate constants, k 2, for the studied reactions with NO 2 − varied between 0.036–0.038 M−1 s−1, and for the reactions with TU between 0.095–1.06 M−1 s−1, respectively. The reaction between TU and the [PtCl(bpma)]+ ion is ten times faster than that of the [PtCl(gly-met-S,N,N)] complex. An analysis of the activation parameters, ΔH ≠ and ΔS ≠, for the selected reactions clearly shows their associative nature.
Keywords: platinum(II) complexes – substitution – kinetics – thiourea – nitrites(III) – iodides
Full paper is available at www.springerlink.com.
Chemical Papers 68 (1) 130–135 (2014)
Friday, December 08, 2023