Comparative analysis of the influence of H-bond strength and solvent on chelate cooperativity in H-bonded supramolecular complexes
Comparative analysis of the influence of H-bond strength and solvent on chelate cooperativity in H-bonded supramolecular complexes
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DOI：
10.1039/c2sc20358h
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发表时间：
2012-01-01
期刊：
影响因子：
8.4
通讯作者：
Turega, Simon M.
中科院分区：
文献类型：
--
作者：
Hunter, Christopher A.;Misuraca, Maria Cristina;Turega, Simon M.
在1，1，2，2-四氯乙烷溶液中测定了24种不同络合物分子内醚-酚氢键的自由能贡献。采用高通量UV/维斯滴定法结合化学双突变体循环，研究了不同官能团相互作用对120种不同锌卟啉-吡啶配体配合物稳定性的影响。TCE中分子内醚-苯酚相互作用的有效摩尔浓度范围为70 mM至400 mM，取决于结合伴侣的互补性。这些值实际上与甲苯中相同醚-苯酚相互作用测得的相应有效摩尔浓度相同。醚配体进行了比较与类似的配体，其中具有膦酸二酯氧氢键受体位于相同的网站上的醚氧的配体框架。在TCE中测量的醚-苯酚相互作用的有效摩尔浓度几乎与嵌入在相同超分子结构中的膦酸二酯-苯酚H-键测量的相应值相同。实验结果与之前的膦酸二酯复合物的结果相矛盾，并表明有效摩尔浓度是分子框架的一个属性，并且与溶剂无关。
Free energy contributions due to intramolecular ether-phenol H-bonds were measured for 24 different complexes in 1,1,2,2-tetrachloroethane solution. High throughput UV/Vis titrations were used in combination with chemical double mutant cycles to dissect out the contributions of different functional group interactions to the stabilities of 120 different zinc porphyrin-pyridine ligand complexes. The effective molarities for intramolecular ether-phenol interactions in TCE range from 70 mM to 400 mM depending on the complementarity of the binding partners. The values are practically identical to the corresponding effective molarities measured for the same ether-phenol interactions in toluene. The ether ligands were compared with analogous ligands, which have a phosphonate diester oxygen H-bond acceptor located at the same site on the ligand framework as the ether oxygen. The effective molarities for the ether-phenol interactions measured in TCE are practically identical to the corresponding values measured for phosphonate diester-phenol H-bonds embedded in the same supramolecular architecture. The experiments contradict the previous results obtained for the phosphonate diester complexes and suggest that effective molarity is a property of the molecular framework and is independent of the solvent.