Solution thermodynamics of geometrical isomers of pyridino calix(4)arenes and their interaction with the silver cation. The X-ray structure of a 1:1 complex of silver perchlorate and acetonitrile with 5,11,17,23-tetra-tert-butyl-[25,26,27,28-tetrakis(2- pyridylmethyl)oxy]calix(4)arene
Solution thermodynamics of geometrical isomers of pyridino calix(4)arenes and their interaction with the silver cation. The X-ray structure of a 1:1 complex of silver perchlorate and acetonitrile with 5,11,17,23-tetra-tert-butyl-[25,26,27,28-tetrakis(2- pyridylmethyl)oxy]calix(4)arene
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吡啶基杯(4)芳烃几何异构体的溶液热力学及其与银阳离子的相互作用。
DOI：
10.1039/a805430d
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发表时间：
1998
期刊：
影响因子：
--
通讯作者：
F. J. S. Velarde
中科院分区：
文献类型：
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作者：
A. F. Namor;O. Piro;L. E. P. Salazar;Adolfo F. Aguilar;Nawar Al;E. Castellano;F. J. S. Velarde
本文报道了吡啶杯（4）芳烃的三种几何异构体{5，11，17，23-叔丁基-[25，26，27，28-四（正吡啶甲基）氧基]-对叔丁基杯（4）芳烃，n=2，3，4}在298.15K时在各种溶剂中的溶解度和标准吉布斯自由能。溶剂化效应从这些配体的标准转移吉布斯能进行评估，使用乙腈作为参考溶剂。对于2-吡啶基衍生物在醇中的醇的脂肪链长度的增加，溶剂-配体相互作用的程度增加，而对于3-和4-吡啶基衍生物，观察到相反的。报道了4-吡啶衍生物在甲醇中298.15K时的质子化常数。结果表明，这些配体的基本性质顺序为：4-吡啶基>3-吡啶基>2-吡啶基杯（4）芳烃。这些大环化合物（2和4-吡啶衍生物）和银阳离子在乙腈中络合的热力学参数表明，作为酚氧和吡啶氮之间的距离增加，络合的强度降低。将银和2-吡啶基杯（4）芳烃衍生物络合的热力学数据与钠和该配体在相同溶剂中的相应值进行比较。结果表明，2-吡啶衍生物提供酚氧和吡啶氮作为与银络合的活性中心。这是证实了该配体和银在CD 3 CN在298 K的1 H NMR测量。的晶体结构的1：1的单乙腈和银配合物的2-吡啶基衍生物与高氯酸盐作为抗衡离子已确定从XRD数据。该物质的晶体结构为四面体空间群P4/n，a=15.580（2）A，c=13.082（2）A，z=2。该大环位于四重对称轴上，由两个锥形部分组成，一个是疏水的，填充有乙腈分子，另一个是亲水的，通过醚氧[d（Ag···O）=2.923（3）A]和吡啶氮原子[d（Ag···N）=2.483（5）A]包封Ag+离子。Ag+离子周围的配位具有扭曲的阿基米德正方形反棱柱的形式。证明了大环化合物在其亲水性空腔中络合银阳离子的能力。
The solubility and derived standard Gibbs energies of solution of three geometrical isomers of pyridinocalix(4)arenes {5,11,17,23-tert-butyl-[25,26,27,28-tetrakis-(n-pyridylmethyl) oxy]-p-tert-butylcalix(4)arene, with n=2, 3, 4} in a variety of solvents at 298.15 K are reported. Solvation effects are assessed from the standard transfer Gibbs energies of these ligands, using acetonitrile as the reference solvent. For the 2-pyridyl derivative in alcohols as the aliphatic chain length of the alcohol increases, the extent of solvent–ligand interaction increases, whereas for the 3- and the 4-pyridyl derivatives the opposite is observed. The protonation constants for the 4-pyridyl derivative in methanol at 298.15 K are reported. The results, compared with corresponding values for the 3-pyridyl derivative show that the basic character of these ligands follows the sequence; 4-pyridyl>3-pyridyl>2-pyridyl calix(4)arene. Thermodynamic parameters for the complexation of these macrocycles (2 and 4-pyridyl derivatives) and the silver cation in acetonitrile show that, as the distance between the phenolic oxygens and the pyridyl nitrogens increases, the strength of complexation decreases. Thermodynamic data for the complexation of silver and the 2-pyridylcalix(4)arene derivative are compared with corresponding values for sodium and this ligand in the same solvent. The results suggest that the 2-pyridyl derivative provides phenolic oxygens and pyridyl nitrogens as the active sites for complexation with silver. This is corroborated by 1H NMR measurements of this ligand and silver in CD3CN at 298 K.The crystal structure of a 1:1 monoacetonitrile and silver complex of the 2-pyridyl derivative with perchlorate as the counter-ion has been determined from XRD data. The substance crystallises in the tetragonal space group P4/n with a=15.580(2) A, c=13.082(2) A, and z=2. The macrocycle is sited on a fourfold symmetry axis and consists of two conical parts, one hydrophobic, filled with an acetonitrile molecule, the other hydrophilic, encapsulating the Ag+ ion through the ethereal oxygen [d(Ag···O)=2.923(3) A] and pyridine nitrogen atoms [d(Ag···N)=2.483(5) A]. The coordination around the Ag+ ion has the form of a distorted Archimedean square antiprism. The ability of the macrocycle to complex the silver cation in its hydrophilic cavity is demonstrated.