Borovkov Victor V, Lintuluoto Juha M, Sugeta Hiromu, Fujiki Michiya, Arakawa Ryuichi, Inoue Yoshihisa
Inoue Photochirogenesis Project, ERATO, JST, 4-6-3 Kamishinden, Toyonaka-shi, Osaka 560-0085, Japan.
J Am Chem Soc. 2002 Mar 27;124(12):2993-3006. doi: 10.1021/ja0172520.
Complexation mechanism, binding properties and thermodynamic parameters of supramolecular chirality induction in the achiral host molecule, syn (face-to-face conformation) ethane-bridged bis(zinc porphyrin), upon interaction with chiral monoamine and monoalcohol guests have been studied by means of the UV-vis, CD, (1)H NMR, and ESI MS techniques. It was found that the chirogenesis process includes three major equilibria steps: the first guest ligation to a zinc porphyrin subunit of the host (K(1)), syn to anti conformational switching (K(S)), and further ligation by a second guest molecule to the remaining ligand-free zinc porphyrin subunit (K(2)), thus forming the final bis-ligated species possessing supramolecular chirality. The validity of this equilibria model is confirmed by the excellent match between the calculated and experimentally observed spectral parameters of the bis-ligated species. The second ligation proceeds in a cooperative manner as K(2) > K(1) for all supramolecular systems studied, regardless of the structure of the chiral ligand used. The binding properties are highly dependent on the nature of the functional group (amines are stronger binders than alcohols) and on the structure of the chiral guests (primary and aliphatic amines have overall binding constant values greater than those of secondary and aromatic amines, respectively).
通过紫外可见光谱、圆二色光谱、核磁共振氢谱和电喷雾电离质谱技术，研究了非手性主体分子syn（面对面构象）乙烷桥联双（锌卟啉）与手性单胺和单醇客体相互作用时超分子手性诱导的络合机制、结合性质和热力学参数。结果发现，手性生成过程包括三个主要平衡步骤：第一个客体与主体的锌卟啉亚基连接（K(1)）、顺式到反式构象转换（K(S)），以及第二个客体分子与剩余的无配体锌卟啉亚基进一步连接（K(2)），从而形成具有超分子手性的最终双连接物种。双连接物种的计算光谱参数与实验观测光谱参数之间的极佳匹配证实了该平衡模型的有效性。对于所有研究的超分子体系，无论所使用的手性配体结构如何，第二个连接都以协同方式进行，因为K(2) > K(1)。结合性质高度依赖于官能团的性质（胺类比醇类是更强的结合剂）以及手性客体的结构（伯胺和脂肪族胺的总结合常数分别大于仲胺和芳香族胺）。
