Ballester Pablo, Claudel Mickaël, Durot Stéphanie, Kocher Lucas, Schoepff Laetitia, Heitz Valérie
Institute of Chemical Research of Catalonia (ICIQ), Avgda. Països Catalans 16, 43007 Tarragona (Spain).
Institution for Research and Advanced Studies (ICREA), Passeig Lluís Companys, 23, 08010 Barcelona (Spain).
Chemistry. 2015 Oct 19;21(43):15339-48. doi: 10.1002/chem.201502152. Epub 2015 Sep 4.
The synthesis of a zinc(II) porphyrin 1 with four appended triazolyl-pyridine chelates is reported. Complexation of the porphyrin peripheral ligands with Ag(I) ions in a 1:2 binding stoichiometry afforded quantitatively the coordination cage Ag4 (1)2 . The assembly and disassembly processes of the cage were investigated in solution using UV/Vis spectroscopy. The mathematical analysis of the data obtained in the UV/Vis titration of 1 with Ag(I) confirmed the assembly in CH2 Cl2 /MeOH (90:10) solution of a species having a 1:2 porphyrin/silver stoichiometry and assigned to it an overall stability constant of 5.0×10(26) M(-5) . The use of a model system allowed an independent assessment of a microscopic binding constant value (Km ) for the interaction between the triazolyl-pyridine ligand and Ag(I) . The coincidence that existed between the Km values extracted from the model system and the titration of 1 provided an indication of the quality and fit of the data analysis. It also allowed the calculation of the average effective molarity (EM) value for the three intramolecular processes that led to the cage assembly as 2.6 mM. Simulated speciation profiles supported the conclusion that at millimolar concentration and working under strict stoichiometric control of the silver/porphyrin ratio, the cage Ag4 (1)2 was the species exclusively assembled in solution. On the other hand, when the concentration of added Ag(I) was approximately 2.6 mM, 50 % of the coordination cage disassembled into open aggregates.
报道了一种带有四个附加三唑基吡啶螯合物的锌（II）卟啉1的合成。卟啉外围配体与Ag（I）离子以1:2的结合化学计量比进行络合，定量得到配位笼Ag4 (1)2 。使用紫外/可见光谱在溶液中研究了该笼的组装和解组装过程。对1与Ag（I）进行紫外/可见滴定所获得数据的数学分析证实，在CH2 Cl2 /MeOH（90:10）溶液中组装了一种卟啉/银化学计量比为1:2的物质，并赋予其5.0×10(26) M(-5)的总稳定常数。使用模型系统能够独立评估三唑基吡啶配体与Ag（I）之间相互作用的微观结合常数（Km）值。从模型系统中提取的Km值与1的滴定之间存在的一致性表明了数据分析的质量和拟合度。这也使得能够计算导致笼组装的三个分子内过程的平均有效摩尔浓度（EM）值为2.6 mM。模拟的物种形成曲线支持了这样的结论：在毫摩尔浓度下且在银/卟啉比例的严格化学计量控制下工作时，笼Ag4 (1)2 是唯一在溶液中组装的物种。另一方面，当添加的Ag（I）浓度约为2.6 mM时，50%的配位笼分解成开放聚集体。
