新型铌氧簇过渡金属衍生物的合成、结构及其催化光解水性质研究

Polyoxoniobates (PONs) have a wide range of potential applications in nuclear-waste treatment, virology, and base-catalyzed decomposition of biocontaminants, while the applications of transiton metal-based complexes are even more extensive. Whereupon, the incorporation of transtion-metal (TM) into PONs presumably represents an intriguing strategy for obtaining novel TM-based PONs derivatives with broader application prospects and it has become an active area of research. However, the expansion of the field of polyoxoniobates is severely limited by the difficulty in controlling the synthesis. In particular, the narrow window of pH values for solution polyoxoniobate chemistry lies around 10.5-12.5 for reactions under ambient conditions, in which the TM cations hydrolyze as expected. Still, it is an ongoing challenge to incorporate TMs into PON clusters or materials. Given these difficulties, there is a urgent need to develop new approaches to extended polyoxoniobate-based derivatives, which is especially important owing to their unique basic properties and potential for catalysis, for example in water splitting. Based on the previous work, first, we aim to explore not only the new approaches to prepare novel PONs that will further react with TM cations to give PON-TM derivatives, but also the preparation conditions of these compounds, which would be characterized systemically by IR, UV/vis, elemental analysis, NMR, and single-crystal X-ray diffraction. Then, we will study the physical and chemical properties of such compouds, peculiarly the property of water-splitting photocatalysis because some polyoxoniobates are of particular interest and have been shown to be overall water-splitting photocatalysts in order to get some new findings in polyoxoniobate chemistry. Furthermore, the correlation among stuctures, components and properties will also be carried out so as to find the key factors influencing the properties. That, in turn, would optimize some characteristics by assembling the components and structures and eventually acquire some compounds bearing benign properties and potential applications. Although there are some reports on PONs, it is surprising that we do not know enough about the reactivities and the intramolecular bonding modes. The development of polyoxoniobates is still at an early stage and may provide an avenue for further expansion of polyoxoniobate chemistry. In conclusion, our efforts focus on the acquisition of such PON-based derivatives with important potential applications, which not only enrich their the structural diversities and further broaden their research fields, but also play a leading role in the knowledge accumulation, technology reserves and theoretical studies of the developments of polyoxoniobate chemistry.

铌氧簇在多个领域具有重要应用前景，由过渡金属构成的化合物应用更为广泛，二者的结合有望得到具有重要应用价值的化合物。多铌氧簇阴离子只存在于碱性条件，而过渡金属阳离子在此条件下发生水解，这就使得多铌氧簇过渡金属衍生物制备急需技术上的突破，极具挑战性。本项目旨在利用相转移和非共溶体系扩散的方法，探索新型铌氧簇及其与过渡金属离子反应制备多铌氧簇过渡金属衍生物的条件，对得到的化合物进行表征。研究化合物的理化性质，重点是催化光解水的性能，以期在铌氧簇化学方面有新的发现；同时研究化合物结构、组成和性质之间的相关性，通过组成和结构的调整，优化其特性，以期得到具有应用前景的化合物。铌化学是一个需探索的研究领域，对其反应活性和分子内键合模式的深入研究将可能催生具有指导意义的理论和重要应用前景的化合物，这不仅可以丰富铌化合物的结构类型，拓宽铌化合物的研究领域，而且对铌化学发展的知识积累和技术储备具有重要意义。

多金属氧簇作为一大类结构明确且在多个领域具有重要应用价值和应用前景的化合物，受到了各国化学家的高度重视。国内外开展的有关多金属氧簇研究主要集中在以钼、钨、钒为主要构成元素的多金属氧簇阴离子形成的化合物方面。由于铌元素的化学惰性，有关铌氧簇的研究相对要少得多。近来研究发现，铌氧簇具有独特的性质，在多个领域具有重要应用前景。过渡金属构成的化合物应用非常广泛，二者的结合有望得到结构新颖的化合物并具有重要应用前景的化合物。由于多铌氧簇阴离子只存在于碱性条件，而过渡金属阳离子在此条件下易发生水解，这就使得多铌氧簇过渡金属衍生物制备急需技术上的突破，极具挑战性。.本项目系统探索了铌氧簇的稳定条件及铌氧簇在溶液中的存在状态，通过采用水热法、水热-扩散法、恒温水浴法、双氧水体系调控法及多羧酸体系调控法，开展了铌氧簇过渡金属衍生物、铌氧簇稀土金属衍生物、杂多铌氧簇及其衍生物、取代型铌氧簇的设计与合成，得到了30余例新的多铌氧簇衍生物，发现了多种新的结构类型，并发展了水热-扩散、多羧酸体系调控等合成铌氧簇衍生物的新方法。在制得新型铌氧簇的基础上，开展了新型铌氧簇催化光解水性质研究，发现铌氧簇对光解水具有催化活性，但含过氧基团的铌氧簇由于过氧基团的存在，催化活性减弱；得到了1例具有单分子磁体特性的铌氧簇衍生物，并开展了铌氧簇作为催化剂的碱性催化研究；项目发表论文20篇，还有多篇正在整理之中；项目培养毕业博士研究生2名，硕士研究生4名，在读博士研究生1名、硕士研究生1名。.本项目铌氧簇合成方法的探索、形成及新型铌氧簇的获得，将为设计、合成新型铌氧簇衍生物提供新的思路，并为铌氧簇衍生物的应用奠定基础。