Danil de Namor Angela F, Aguilar-Cornejo Adolfo, Soualhi Rachida, Shehab Mohammed, Nolan Kevin B, Ouazzani Naaila, Mandi Laila
Laboratory of Thermochemistry, Chemistry Division, School of Biomedical and Molecular Sciences, University of Surrey, Guildford, Surrey GU2 7XH, United Kingdom.
J Phys Chem B. 2005 Aug 4;109(30):14735-41. doi: 10.1021/jp0514630.
The interaction of a calix(4)arene derivative, namely 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetra[2-(4-pyridyl)methoxy]calix(4)arene, 1a, and its monomeric component, p-tert-butylphenoxy-4-pyridine, 1b, with metal cations has been investigated in acetonitrile and methanol. (1)H NMR measurements carried out in CD(3)CN show the primary role played by the pyridyl nitrogens in their complexation with metal cations. Conductance measurements demonstrated that for all cations (except mercury) the composition of the metal ion complexes of 1a is 1:1 (ligand:metal cation). However, 1a hosts two mercury cations per unit of ligand. For the monomer 1b, complexes of 2:1 (ligand:metal cation) stoichiometries are formed with the exception of Pb(2+) (1:1 composition). The thermodynamics of complexation of these systems are reported in acetonitrile. Data in methanol are limited to stability constant values for mercury(II) and these ligands. This paper demonstrates for the first time that thermodynamic data for the complexation of the monomeric component of the ligand and metal cations contribute significantly to the interpretation of systems involving cation-calixarene interactions in solution.
已在乙腈和甲醇中研究了杯[4]芳烃衍生物5,11,17,23-四叔丁基-25,26,27,28-四[2-(4-吡啶基)甲氧基]杯[4]芳烃（1a）及其单体成分对叔丁基苯氧基-4-吡啶（1b）与金属阳离子的相互作用。在CD₃CN中进行的¹H NMR测量表明吡啶基氮在它们与金属阳离子络合中起主要作用。电导测量表明，对于所有阳离子（汞除外），1a的金属离子络合物组成均为1:1（配体:金属阳离子）。然而，每个配体单元1a容纳两个汞阳离子。对于单体1b，除Pb²⁺（组成为1:1）外，形成化学计量比为2:1（配体:金属阳离子）的络合物。报道了这些体系在乙腈中的络合热力学。甲醇中的数据仅限于汞(II)和这些配体的稳定常数。本文首次证明，配体单体成分与金属阳离子络合的热力学数据对解释溶液中涉及阳离子-杯芳烃相互作用的体系有显著贡献。
