ortho-Phenylenes in Complex Foldamer Architectures

化学系的大分子、超分子和纳米化学项目支持C.迈阿密大学化学生物化学系的斯科特·哈特利说。在自然界中，大分子的结构复杂性（例如，蛋白质），并最终其功能，是由较小的分子片段（低聚物和聚合物）的折叠产生的。这一事实激发了许多研究非生物“折叠体”的努力，即以明确定义的方式折叠的较小分子片段。哈特利小组的研究重点是邻苯，这是一类由直接连接的芳环形成的简单折叠体。在这个项目中，哈雷小组开发了控制邻苯折叠的方法，并将环纳入更复杂的结构中。该项目涉及研究生、大学生和高中教师，他们利用有机合成、计算化学和各种表征方法，努力理解分子折叠、自组装和分子识别的基本概念。邻苯联合收割机结合了几个使其成为“下一代”折叠体的特征。 它们很容易合成。 它们的折叠行为很容易使用简单，廉价的方法建模。 其精确的溶液相折叠状态可以通过NMR光谱来表征。该项目有三个具体目标，利用这些特点。首先，邻亚苯基折叠的扭转方向是使用手性端基控制的。虽然这种对低聚物折叠的控制已经在其他系统中得到证实，但它对邻苯的更高级用途至关重要。 如果成功，可用于测试邻苯的自旋选择性电子传输。第二，邻亚苯基亚基连接在一起形成大环。这个简单的体系代表了向引入邻亚苯基二级结构（即，螺旋）转化为更高级的结构，并提供了一个框架来测试桥接折叠体亚基之间的构象相互作用。最后，邻亚苯基用大环官能化以沿其侧面沿着产生结合位点。该体系结构代表了基于邻亚苯基的分子识别的第一步。

The Macromolecular, Supramolecular, and Nanochemistry Program of the Chemistry Division supports the work of Prof. C. Scott Hartley in the Department of Chemistry & Biochemistry at Miami University. In nature, the structural complexity of large molecules (e.g., proteins), and ultimately their function, is generated by the folding of smaller molecular pieces (oligomers and polymers). This fact has inspired many efforts to study non-biological "foldamers" smaller molecular pieces that fold in well-defined ways. Research in the Hartley group focuses on the ortho-phenylenes, a simple class of foldamers formed from directly connected aromatic rings. In this project, the Harley group develops methods to control the folding of o-phenylenes and incorporates the rings into more complex structures. The project involves graduate students, undergraduates, and high-school teachers working to understand fundamental concepts of molecular folding, self-assembly, and molecular recognition, using the techniques of organic synthesis, computational chemistry, and various characterization methods.The ortho-phenylenes combine several features that make them attractive as "next-generation" foldamers. They are straightforward to synthesize. Their folding behavior is easily modeled using simple, inexpensive methods. Their exact, solution-phase folding state can be characterized by NMR spectroscopy. This project has three specific aims that take advantage of these features. First, the twist-sense of o-phenylene folding is controlled using chiral end groups. While this sort of control over oligomer folding has been demonstrated in other systems, it is critical for more advanced uses of o-phenylenes. If successful, may be used to test o-phenylenes for spin-selective electron transport. Second, o-phenylene subunits are linked together into macrocycles. This simple system represents a first step toward incorporating o-phenylene secondary structures (i.e., helices) into higher-order structures, and provides a framework to test the conformational interaction between bridged foldamer subunits. Finally, o-phenylenes are functionalized with macrocycles to create binding sites along their sides. The architectures represents a first step toward o-phenylene-based molecular recognition.