功能无机超分子聚合物

There is an increasing demand on the replacement of fossil fuel by other renewable alternatives due to the environmental problem associated with the use of carbon based fuels. Among all renewable resources, solar energy is one of the most prominent candidates. Indeed, the solar energy to the earth is more than surplus. The captured solar energy can either be converted into electricity by solar cells or stored as chemical.fuels by solar-driven water splitting. Nevertheless, functional materials are required for the harvesting and harnessing of solar energy into electrical or chemical fuels. Metallosupramolecules have received considerable attention not only because they have potential applications in molecular recognition and catalysis, but also because they possess interesting quantum effects and accordingly may be used as.building blocks for molecular electronics and spintronics. Nowadays, many different types of metallosupramolecules including metallacrowns,.metallacalixarenes, metallahelicates, metallacryptates, metallacoronates, molecular wheels, metal-containing cages and polyhedra have been evolved. Among them, the molecular wheel is particularly attractive because of its resemblance to the wheel-like light harvesting antenna complex in photosynthetic purple bacteria. .Indeed, oxygen-bridged molecular wheels containing paramagnetic metal ions are well known for their single molecular magnetism. These single molecule magnets (SMMs) could be used as building blocks for information storage in quantum computations. However, the exploration and application of molecular wheels are greatly hampered by the lack of a general synthetic strategy and low product yields..Despite the rich structural chemistry, high biological relevance, and the semiconducting properties demonstrated by metal chalcogenides,.sulfur(chalcogen)-bridged molecular wheels are sparse in literature. We have demonstrated a reliable synthesis of chalcogenolate bridged molecular wheels in moderate to good yields (40-85 %). In this proposal, we propose to develop functional metallacycles with/without long-lived electronic excited state for catalysis and energy conversion. These studies will provide better understanding of the electronic, optical and photophysical properties of the wheel chemistry and subsequently lead to better insight into the design of functional molecular wheels.

无机超分子聚合物已经收到相当大的关注，不仅因为他们在分子识别和催化的应用，还因为他们具有有趣的量子效应，因此可被用作构建块分子电子学和自旋电子学。在不同类型的无机超分子聚合物，金属环是特别有吸引力的。因为它的车轮状形与光合紫细菌的捕光天线复合物相似., 这有利其在人工光合作用的应用。 例如由于光吸收许可横截面显著增加, 所以在低光照条件下仍能收集阳光及在轮状结构中激发态分子比较集中,这有利于进行连续多个光诱导的电子转移反应。.事实上，含氧桥连及顺磁金属离子的金属环已经展示具有单分子磁性的特性。这些单分子磁体可以可在量子计算器中被用作信息存储。然而在缺乏合成路线和低产量的影响下, 金属环的探索和应用受到极大的限制。尽管拥有丰富的结构化学、高生物相关性和半导体的特性。在文献上,以硫作桥联的金属环的报告相对比较少。我们已经证明硫可作桥连合成含钌和锇的金属环并且能取得中度至良好的产量。 .本項目主要探索如何有策略地以簡單及高產率的方法合成金属分子环並通過研究其特性從而有助設計具功能性的金属分子以应用在能源领域。

能源问题是本世纪人类面临最大的挑战之一。在全球超过70 亿人口压力下, 人类对化石燃料的需求持续增长. 然而化石燃料是非可再生能源,人类必须致力发展可替代化石燃料的可再生能源以满足不断增加的需求。近年, 由小分子自組裝而成的超分子体系，如金属有机框架或者有机金属大环化合物在能源领域的研究吸引了众多科学家的兴趣。例如美国的Yaghi、日本的Kitawaga、中山大学陈小明院士以及东北师范大学苏忠民教授在金属有机框架储小分子如氢气 及二氧化碳的研究上取得重要成果, 大大提高了将来使用氢气作为燃料的可行性。而诺贝尔学奖得主Jean-Marie Lehn, 美国学者Kenneth N. Raymond 及Peter J.Stang, 日本的Makoto Fujita, 国内著名学者洪茂椿院士及金国新教授这些学者则发现有机金属大环化合物可以应用在超分子催化和传输过程, 这对于超分子电子学和光学分子器件的设计和构建建立了重要的基础。而本项目的立足点亦建立在研究金属分子环的合成以及其作为超分子催化剂应用于能源转换方面上的应用。但是在合成有机金属分子环的前配体时，我们意外地发现许多金属无机小分子在光电性能上能与许多金属无机超分子向媲美，并且由于这些无机小分子具有结构上易于修饰，合成方法成熟等优点，因此，对一些新型的无机小分子的研究将有利于我们进一步探索功能无机超分子的结构与性能的关系。在本项目中，我们成功地制备了钌（ii）配合物Ru[(tpa)(bt)]Cl4并且发现该配合物具有抑制β-类淀粉蛋白（Beta-Amyloid, Aβ）纤维化聚集的作用。我们还发现不同配位阴离子的钴（Ⅱ）金属配合物[Co(TPA)X][Cl]( X=Cl, Br, I, NCS)具有作为光催化二氧化碳还原催化剂的潜质。最后，我们还成功地制备了一系列双氮杂卡宾类铱(iii)配合物并且将这系列的配合物应用于光催化反应以及研究了它们的生物抗癌活性。