Beijing National Laboratory for Molecular Sciences, The Key Laboratory of Bioorganic Chemistry and Molecular Engineering of the Ministry of Education, College of Chemistry and Molecular Engineering Department, Peking University, Beijing 100871, China.
Chemistry. 2010 Dec 10;16(46):13850-61. doi: 10.1002/chem.201001606.
A family of macrocycles with oligo(ethylene glycol) chains, 4O, 5O, and 6O, was developed to construct a series of new incorporated macrocycles through dynamic covalent chemistry. These flexible macrocycles exhibited excellent "self-sorting" abilities with diamine compounds, which depended on the "induced-fit" rule. For instance, the host macrocycles underwent conformational modulation to accommodate the diamine guests, affording [1+1] intramolecular addition compounds regardless of the flexibility of the diamine. These macrocycles folded themselves to fit various diamines with different chain length through modulation of the flexible polyether chain, and afforded intramolecular condensation products. However, if the chain of the diamine was too long and rigid, oligomers or polymers were obtained from the mixture of the macromolecule and the diamine. All results demonstrated that inclusion compounds involving conformationally suitable aromatic diamines were thermodynamically favorable candidates in the mixture due to the restriction of the macrocycle size. Furthermore, kinetic and thermodynamic studies of self-sorting behaviors of both mixed 4O-5O and 4O-6O systems were investigated in detail. Finally, theoretical calculations were also employed to further understand such self-sorting behavior, and indicated that the large enthalpy change of H(2)NArArNH(2)@4O is the driving force for the sorting behavior. Our system may provide a model to further understand the principle of biomolecules with high specificity due only to their conformational self-adjusting ability.
开发了一类具有聚乙二醇链的大环化合物 4O、5O 和 6O，通过动态共价化学构建了一系列新的包含大环的化合物。这些柔性大环与二胺化合物表现出优异的“自分类”能力，这取决于“诱导契合”规则。例如，主体大环通过构象调节来容纳二胺客体，形成[1+1]分子内加成化合物，而不管二胺的柔韧性如何。这些大环通过调节柔性聚醚链来折叠自身以适应具有不同链长的各种二胺，从而形成分子内缩合产物。然而，如果二胺的链太长且刚性，则混合物中会得到寡聚物或聚合物。所有结果表明，由于大环尺寸的限制，包含构象合适的芳香族二胺的包合物是混合物中热力学有利的候选物。此外，详细研究了混合 4O-5O 和 4O-6O 体系的自分类行为的动力学和热力学。最后，还进行了理论计算以进一步理解这种自分类行为，并表明 H(2)NArArNH(2)@4O 的大焓变是排序行为的驱动力。我们的系统可能为进一步理解仅由于其构象自调节能力而具有高特异性的生物分子的原理提供一个模型。
