The Substitution Reactions of the Small Biomolecules and Dinuclear Pt(II) Complexes with Alkanediamine Linker |
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| Authors: | Enisa Selimovi? Jovana Bogojeski |
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| Institution: | 1. Department of Chemical‐Technological Sciences, State University of Novi Pazar, Vuka Karad?i?a bb, Novi Pazar, Serbia;2. Department of Chemistry, Faculty of Science, University of Kragujevac, Kragujevac, Serbia |
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| Abstract: | The substitution reactions of the complexes {trans‐Pt(NH3)2H2O}2(μ‐1,4‐diaminobutane)]4+ ( I ), {trans‐Pt(NH3)2H2O}2(μ‐1,6‐diaminohexane)]4+ ( II ), and {trans‐Pt(NH3)2H2O}2(μ‐1,8‐diaminooctane)]4+ ( III ), with nucleophiles L‐cysteine (L‐Cys), glutathione (GSH), guanosine‐5′‐monophosphate (5′‐GMP), L‐histidine (L‐His), and pyridine were studied in 0.1 M NaClO4 aqueous solutions at pH = 2.5. The substitutions were studied under pseudo‐first‐order conditions as a function of concentration and temperature using UV–vis spectrophotometry. At three different temperatures (288, 298, and 308 K) the reactions of the II and III complexes and 5′‐GMP were studied. The order of reactivity of study ligands is L‐Cys > GSH > 5′‐GMP > L‐His > pyridine and the order of reactivity of the complexes is I < II ≈ III . The obtained results indicate that the structure of the alkanediamine linker in the dinuclear Pt(II) complexes controls the substitution process. The negative values reported for entropy of activation confirmed the associative substitution mode. These results are discussed in order to find the connection between structure and reactivity of the dinuclear Pt(II) complexes. |
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