Structural Recognition in Complexation of Organic Compounds (Chemistry)

本研究由有机与大分子化学计划资助。这项研究包括构建分子，模仿大自然选择性复杂和进行高度选择性反应的能力。与酶相比，模型分子相对较小，但基于对相关因素的理解，构建模型分子是为了模拟酶的选择行为。克拉姆博士是这项工作的先驱，并最终获得了诺贝尔奖。目标是了解有机化合物之间络合的结构识别。生物系统中的分子交通控制主要依赖于络合中的结构识别，并激发了对简单非生物系统络合的研究。具有聚合结合位点（宿主）的有机化合物被设计和制备成与其他具有互补、发散结合位点（客体）的有机化合物络合。这个假设正在被验证，“更强和更具体的络合作用适用于主客合作伙伴，其内在结构在络合作用之前强制组织结合（预组织）。”宿主和配合物的结构来源于晶体结构、核磁和质谱以及元素分析。络合的自由能与主客体结构有关。宿主中的预组织是通过刚性分子模块的组装来形成具有碟状、碗状、杯状或花瓶状（空腔）的分子尺寸强制凹表面来实现的。结合或溶解基团组成或从其表面突出。分子细胞是通过在其边缘的多重键合而构成的，两个或更多的空腔形成细胞，其强制内部囚禁有机或无机来访者，其性质随封装而改变。

This research is supported by the Organic and Macromolecular Chemistry Program. The research involves building molecules that mimic nature's ability to selectively complex and carry out highly selective reactions. The model molecules are relatively small compared to enzymes but are built to simulate their selective behavior, based upon an understanding of the responsible factors. Dr. Cram has been a pioneer in this work, it having culminated in his being awarded a Nobel Prize. The goal is to understand structural recognition in complexation between organic compounds. Molecular traffic control in biological systems depends centrally on structural recognition in complexation, and inspires study of complexation with simple non-biological systems. Organic compounds with convergent binding sites (hosts) are designed and prepared to complex other organic compounds with complementary, divergent binding sites (guests). The hypothesis is being tested "that stronger and more specific complexation applies to host-guest partners whose intrinsic structures enforce an organization for binding prior to complexation (preorganization)." Structures of hosts and complexes derive from crystal structures, nuclear magnetic and mass spectra, and elemental analyses. Free energies of complexation are correlated with host and guest structures. Preorganization in hosts is obtained through assembly of rigid molecular modules to form enforced concave surfaces of molecular dimensions with saucer, bowl, cup, or vase-like shapes (cavitands). Binding or solubilizing groups compose or protrude from their surfaces. Molecular cells are constructed by multiply bonding at their rims two or more cavitands to give carcerands, whose enforced interiors imprison organic or inorganic guests, whose properties change with encapsulation.