Host-Guest Complexation of Bisporphyrin Cleft and Electron-Deficient Aromatic Guests
Host-Guest Complexation of Bisporphyrin Cleft and Electron-Deficient Aromatic Guests
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双卟啉裂隙和缺电子芳香族客体的主客体络合
DOI：
10.1021/acs.joc.1c02742
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Takeharu Haino
中科院分区：
文献类型：
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作者：
Naoyuki Hisano;Takeharu Haino
研究了双卟啉裂口与多种缺电子客体分子在溶液和固态下的主客体络合反应。双卟啉与二氢化萘和2,4,7-三硝基芴酮的x射线晶体结构表明，这些客体分子位于双卟啉间隙内，形成了理想的主客体比为1:1的π -π堆积相互作用。等温滴定量热法测定了1,2-二氯乙烷和甲苯中1:1主客体配合物的结合常数和热力学参数。发现了两种类型的焓熵补偿效应：(1)主客体结构的紧密堆叠限制了客体在间隙内的运动，导致了显著的脱溶，固有熵较大。(2)结合较松的客体在双卟啉间隙内保持分子自由，使其溶出较少，固有熵较小。手性客体包封引导双卟啉单位的顺时针和逆时针扭曲构象，从而诱导双卟啉cd。
The host–guest complexation of a bisporphyrin cleft with various electron-deficient guest molecules was studied in solution and in the solid-state. X-ray crystal structures of a bisporphyrin cleft with naphthalene dianhydride and 2,4,7-trinitrofluorenone reveal that these guest molecules were located within the bisporphyrin cleft and formed ideal π–π stacking interactions in a host–guest ratio of 1:1. Isothermal titration calorimetry determined the binding constants and thermodynamic parameters for the 1:1 host–guest complexations in 1,2-dichloroethane and toluene. Two types of enthalpy–entropy compensation effects were found: (1) The tightly stacked host–guest structures restrict guest movement within the cleft, which results in significant desolvation with large intrinsic entropies. (2) The loosely bound guests maintain their molecular freedom within the bisporphyrin cleft, which leads to less desolvation with small intrinsic entropies. Chiral guest encapsulation directed the clockwise and anticlockwise twisted conformations of the bisporphyrin units, which induced bisignate CDs.