巨型轮状和球状铜-氧簇的制备及其性质研究

Studies on giant metal-oxide clusters with highly-symmetrical structures are the recent research highlights on nanomaterials and bioinorganic chemistry. The self-assembly of a few giant metalates has been found by serendipity, and its mechanism remains elusive. The theory of the interplay between different families of {Mox}, {Mnx} and {Pdx} has been proposed by us very recently, suggesting that the correlated numbers, such as 84, 132 and 154, reveal more favored nuclearity in the assembly of giant molecules. It is of vital importance to be tested and strengthened by other families and examples for this theory. Learning from our stock knowledge of {Pd84} torus and other giant molecular wheels and spheres, it is both a challenge and an opportunity for the insight of self-assembly to extend the family to another late transition metal, Cu(II). To construct the giant copper-oxide clusters, two different synthetic strategies of building a dynamic combinatorial library in the as-formed solution and using secondary building blocks will be applied. Experiments will be carried out in aqueous solution with a variety of Cu(II) precusors and soluble inorganic ligands. In this open system, the solution will be exposed to be monitored and modulated, thus the composition of the mixture at equlibrium can be fine-tuned under the thermodynamic control. The details in the synthesis of Cu(II) rings and spheres will be explored, followed by the investigation of their molecular properties, such as magnetism and catalytical behavior. This study will help chemists learn underlying rules of the self-assembly in the complex system, therefore is of significance for nano-scale materials' design and bioinorganic chemistry. What's more, it will be focused on to unravel the structure-function relationship in this study, providing an access of the function-orientated synthesis of desired nanomaterials from the bottom-up approach.

对具有高对称性结构的巨型金属-氧簇的研究,是纳米材料和无机生物学的前沿热点。对其自组装规律的认识，仍只局限在钼、锰和钯簇。在前期研究中，结合这三类金属-氧簇的研究成果，我们探讨了巨型轮簇和球簇与其金属核数的相关性。对这一规律的验证和完善，亟需引入另一种元素作为研究对象。本课题设计以来源广泛、配位方式灵活的铜离子作为研究对象，在我们对水相中制备轮状{Pd84}和铜离子的水解作用已有研究基础上，采用"动态组合化学法"和"建筑块法"，以期制备具有轮状和球状结构的巨型铜-氧簇并研究其性质。本项目以在开放的水相温和反应体系中对铜-氧簇组装进行实时、精细调控为研究特色，不同于传统合成策略中往往着重于有机配体的设计和采用有机溶剂、溶剂热反应法，为突破金属核数超过44的铜-氧簇的制备提供新的研究思路。本项目旨在通过研究此类分子的定向合成和构效关系，为制备具有工业应用价值的新型无机分子材料提供依据。

在该项目研究中，本课题采用“动态组合化学法”和“建筑块法”两种合成策略，通过设计、调控和组合不同实验参数，研究了铜离子在溶液中自组装行为，通过单晶生长的方法，获得可靠的结构数据，并结合其他分析手段，研究其固态和溶液中的物化性能。在一系列的研究探索中，系统性地建立和完善了两个自组装体系：（1）铜盐在水相中与酒石酸配体作用定向制备不同核数的零维簇合物与手性二维层状配位聚合物（铜盐与酒石酸体系）；（2）具有二十核的铜-氧球簇以及基于该球簇结构模型的铜-锌、铜-钴、铜-镍双金属球状簇合物（二十核金属-氧球簇体系）。铜盐与酒石酸体系的调控，不仅证实了该体系中可能存在的动态组装库，仍有大量具有新结构、新性能的铜-氧簇合物及配位聚合物有待探究，如具有高S值的手性铜-氧簇，还提供了一种在温和条件下（常温、水相）可控合成金属-氧簇合物的新方法和思路。二十核金属-氧球簇体系的建立，一方面证实了不同体系中具有高对称性的球状结构的构筑和倾向，另一方面为以该球状簇合物作为模板合成具有更大结构的主体分子的研究，提供了工具和基础。此外，多种金属混杂的球簇合成，也为制备具有优异性能的新型混合金属材料提供了一种新方法。相关研究成果已在Inorganic Chemistry期刊发表3篇论文，目前仍有2篇文章投稿中。