Conformational control of the structure and properties of synthetic porous materials

这是一个长期的基础研究项目，目标是合成像生物分子一样对化学环境做出反应的结晶性多孔材料。尽管合成多孔材料和生物分子之间的潜在类比多年来一直被提出，但由于该项目所基于的结果，我们现在可以第一次有意义地解决这个问题。这将在基础科学和理解方面立即创造机会。多孔材料通过控制气孔中客人的组织来支持现代化学工业的分离和催化过程。这些高性能材料，如沸石和碳，都具有坚硬的结构，无论其化学环境如何都不会改变：在这种单一结构最低限度内的动力学可能很重要，但控制客体反应的孔的大小和形状保持不变。相比之下，参与分类、分离和催化的生物分子可以灵活地对其化学环境做出反应。为了做到这一点，他们使用围绕单键的旋转在客体分子存在的情况下进行重组，在他们的构象能量图景中采用不同的结构。根据最终结构的性质及其与生物分子可达结构状态的关系，这些响应被表征为构象选择和诱导匹配。这通过组织各种空间有序的化学功能来产生精致的化学选择性，这也是生物分子在功能性能方面的特征。相比之下，我们以前还无法制备具有可通过单键旋转获得的可控相互转化结构的合成多孔材料，也没有能够将空间有序的多种化学功能引入合成多孔材料中，这种合成多孔材料可以通过这种单键旋转进行重构。可调节的合成多孔材料可以像生物分子一样对客人做出可控的反应，这将为小分子的分离和转化提供途径，这些小分子与当前合成多孔材料所能达到的不同。在最近发表在《自然》杂志上的一篇论文中，我们报道了一种像生物分子一样对客人做出反应的晶体多孔材料。具体地说，它同时显示了构象选择和诱导FIT响应，这些响应展示了由多孔性材料结构中单键的不同旋转创建的构象能量图景：然后这些响应被用于可控地触发客体摄取。这个项目将确定如何通过创造具有不同结构和化学成分的这种多孔材料的新家族来实现和控制这种客户反应。因此，它将在多孔材料研究中开创一个新的方向。这将通过定义引入能够广泛指导客体反应的各种化学功能所需的合成化学，通过在空间中精确地对多种功能进行排序以及通过扩大孔系统的大小和几何来实现。由此产生的材料将提供新的客体反应模式，通过对产生的结构和相关吸附行为的详细评估来了解这些模式。这将允许基于如何通过化学和顺序的单键旋转来确定客体反应的知识来设计改进的材料。一系列新材料家族具有不同的构象能量景观，跨越孔大小、几何形状和化学功能，通过以前无法访问的机制提供对吸附、分离和催化功能的控制。这将使我们能够评估和了解类生物分子构象反应对合成多孔材料性能的影响。

This is a long-range basic research project that targets the synthesis of crystalline porous materials that respond to their chemical environment in the way that biological molecules do. Although the potential analogy between synthetic porous materials and biological molecules has been suggested for many years, we can now address this problem meaningfully for the first time because of the results on which the project is based. This will create immediate opportunities in fundamental science and understanding.Porous materials underpin the separation and catalysis processes of the modern chemical industry by controlling the organisation of guests in their pores. These high-performing materials, such as zeolites and carbons, all have rigid structures that do not change regardless of their chemical environment: dynamics within this single structural minimum can be important, but the size and shape of the pores that control guest response are unchanged. In contrast, the biological molecules involved in sorting, separation and catalysis can respond in a flexible manner to their chemical environment. To do this, they use rotation about single bonds to restructure in the presence of guest molecules, adopting different structures within their conformational energy landscape. The responses are characterised as conformational selection and induced fit according to the nature of the final structure and its relationship to the accessible structural states of the biological molecule. This produces exquisite chemical selectivity by organising the diverse array of spatially ordered chemical functionality that is also characteristic of biological molecules for functional performance.In contrast, we have not previously been able to prepare synthetic porous materials with controllably interconvertible structures accessible via single bond rotation, nor to introduce spatially ordered multiple chemical functions into a synthetic porous material that could restructure by such single bond rotation. The creation of tuneable synthetic porous materials that can controllably respond to guests as biomolecules do would offer pathways for the separation and transformation of small molecules that are distinct from those accessible to current synthetic porous materials.In a recent paper in Nature, we reported a crystalline porous material that responds to guests like a biological molecule. Specifically, it displays both conformational selection and induced fit responses that demonstrate a conformational energy landscape created by different rotations of single bonds in the porous material structure: these responses are then used to controllably trigger guest uptake. This project will establish how to achieve and control such guest response by creating new families of such porous materials with diverse structure and chemistry. It will thus create a new direction in porous materials research.This will be achieved by defining the synthetic chemistry required to introduce diverse chemical functionality that can broadly direct guest response, by ordering multiple functionalities precisely in space and by expanding the size and geometry of the pore systems. The resulting materials will offer new modes of guest response that will be understood through detailed evaluation of the arising structures and associated sorption behaviour. This will allow the design of improved materials based on knowledge of how to determine guest response through single bond rotation by chemistry and sequence. The range of new materials families with distinct conformational energy landscapes spanning pore sizes, geometries and chemical functionalities offer control of function in sorption, separation and catalysis by previously inaccessible mechanisms. This will allow us to evaluate and understand the impact of biomolecule-like conformational response on the capabilities of synthetic porous materials.