Synthesis and Host-Guest Chemistry of Organically-Functionalized Polyoxomolybdate Wheels

化学中超分子相互作用辅助的主客体包埋过程在药物输送、分离过程和传感应用中具有重要意义。多金属氧酸盐(POMS)是一种离散的阴离子金属氧簇，由于其易于控制其分子性质，如大小、形状、组成、电荷、酸度、氧化还原电位和在水和有机介质中的溶解度，因此对主客体化学具有很大的吸引力。POMS在体内和体外都被证明是高效的抗病毒、抗肿瘤、抗菌和抗糖尿病药物。非常大的、离散的轮状或球状的多钼酸盐(例如，{Mo154}轮状、{Mo132}球状)已经知道&gt；20年了，对于它们作为客体包囊的宿主的作用，人们已经获得了一些有限的见解。然而，使用离散的POM轮子作为宿主，对客体吸收和释放一直到药物输送应用的系统研究在很大程度上还没有被探索。该项目的第一个关键目标是设计和合成离散的、有机功能化的钼氧化合物轮子，并通过主-客体相互作用将它们用于生物医学应用，类似于有机主体如冠醚、环糊精、杯芳烃和葫芦醛。我们还将探讨它们对各种硫醇污染物和硝基炸药的传感行为，以及它们在反应中的催化活性，如有机硫化物的氧化和烯烃的环氧化。该项目的第二个主要目标是建造以POM轮子为基础的延伸型多孔骨架材料，称为金属有机骨架(MOF)，使用单个POM作为辅助建筑单元。这代表了一种很有前途的制备基于POM的MOF材料的策略，它结合了POM和MOF的优点，从而在质子传导、催化和生物医药等领域产生了非常有吸引力的主-客体性质。因此，该项目涉及一个全新的研究领域，很可能导致发现具有临床和/或工业应用潜力的多功能材料。

Host–guest encapsulation processes in chemistry assisted by supramolecular interactions are of importance in drug delivery, separation processes and sensing applications. Polyoxometalates (POMs) are discrete, anionic metal-oxo clusters and attractive for host-guest chemistry because of the ease of controlling their molecular properties, such as size, shape, composition, charge, acidity, redox potential and solubility in aqueous and organic media. POMs have been shown to be highly effective as antiviral, antitumor, antibacterial, and antidiabetic agents both in vitro and in vivo. Very large, discrete wheel- or ball-shaped polyoxomolybdates (e.g. {Mo154} wheel, {Mo132} ball) have been known for >20 years, and some limited insight has been obtained on their role as hosts for guest encapsulation. However, systematic studies on guest uptake and release all the way to drug delivery applications using discrete POM wheels as hosts are largely unexplored. The first key aim of this project is to design and synthesize discrete, organically-functionalized molybdenum-oxo wheels and utilize them for bio-medical applications via host-guest interactions, in analogy to organic hosts such as crown ethers, cyclodextrins, calixarenes and cucurbiturils. We will also explore their sensing behaviour for various thiol contaminants and nitro-explosives, as well as their catalytic activities in reactions, such as the oxidation of organic sulfides and epoxidation of olefins. The second key aim of this project is the construction of POM-wheel-based extended, porous framework materials known as metal-organic frameworks (MOFs), using individual POMs as secondary building units. This represents a promising strategy for generating POM-based MOF materials, which merge the merits of both POMs and MOFs, and hence give rise to highly attractive, host-guest based properties in areas such as proton conduction, catalysis and bio-medicine. This project hence deals with a completely new research field, which is likely to result in the discovery of promising multi-functional materials with the potential for clinical and/or industrial applications.