Cu2+ Coordination Properties of a 2-Pyridine Heptaamine Tripod: Characterization and Binding Mechanism

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• 作者：Alejandra Sornosa Ten ; Nicolas Humbert ; Begoa Verdejo ; Jos M. Llinares ; Mourad Elhabiri ; Julia Jezierska ; Conxa Soriano ; Henryk Kozlowski ; Anne-Marie Albrecht-Gary ; Enrique Garca-Espaa
• 刊名：Inorganic Chemistry
• 出版年：2009
• 出版时间：September 21, 2009
• 年：2009
• 卷：48
• 期：18
• 页码：8985-8997
• 全文大小：1082K
• 年卷期：v.48,no.18(September 21, 2009)
• ISSN：1520-510X

文摘

The synthesis, protonation, and Cu²⁺ coordination chemistry of a tripodal heptaamine ligand (L¹) functionalized with 2-pyridine fragments at the ends of its three branches are reported. L¹ presents six relatively high protonation constants followed by much more reduced constant that as indicated by the UV−vis and NMR data, occur on the pyridine fragments. p[H]-metric, ESI/MS⁺, EPR and UV−vis data show that L¹ is able to form mono-, di-, and trinuclear Cu²⁺ complexes. Slippage movements and molecular reorganizations have been observed to occur as a function of p[H] in the 1:1 Cu²⁺ complexes. The kinetic studies showed that the complex formation is fast and proceeds through a dissociative Eigen−Wilkins mechanism. The decomposition of CuL¹ upon addition of acid excess occurs with two separate kinetic steps; the rate constant for the fast process does not vary with respect to the H⁺ concentration whereas a linear dependence on H⁺ is observed for the slow step.