Polyoxometalates (POMs) are discrete metal-oxygen clusters with different shapes, sizes, and compositions, which provides a variety of structural building units (SBUs) for making novel and robust POM-based cluster-organic frameworks. Therefore, the combination of POM clusters and metal-organic frameworks will open up a new avenue for the creation of a variety of novel functional materials. Recent years, the hydrothermal technique proved to be a particularly powerful synthetic means of making crystals of numerous organic-inorganic hybrids. In this paper, three organic-inorganic hybrid open- frameworks constructed from different types of polyoxoanion cluster units and Cu-(2-ptz) (2-ptz=5-(2-pyridyl)-tetrazole) complexes, Cu4(2-ptz)4(H2O)7SiW12O40·4H2O (1), Cu5(2-ptz)6(OH)(H2O)3PW12O40·H2O (2), Cu9(μ-O)6(2-ptz)6(H2O)9-(H6P2W18O62)·3H2O (3) have been hydrothermally made and structurally characterized by elemental analyses, infrared spectrum (IR) spectroscopy, thermogravimetric (TG) analyses, ultraviolet-visable diffuse reflectance spectrum (UV-DSR), powder X-ray diffractions (PXRD), and single-crystal X-ray structural analyses, respectively. Structure analyses reveal that compounds 1～3 are three-dimensional (3-D) frameworks. The structure of 1 is built up of the isolated zigzag Cu-(2-ptz) complex segments and SiW12O404- clusters; 2 is constructed from the 2-D Cu-(2-ptz) networks and PW12O403- cluster pillars; while 3 is made of the linear Cu-(2-ptz) chains and PW18O626- clusters. Magnetic measurements indicated that compounds 1 and 2 exhibit antiferromagnetic interactions between Cu ions, while compound 3 display ferrimagnetic coupling behavior. UV-DSR spectra indicate that compounds 1～3 are potential semiconductor materials. The successfully syntheses of compounds 1～3 not only testify that the shapes and the number of negative charges of POM anions have an important influence on the self-assembly of organic-inorganic hybrid POM-based materials, but also may open up possibilities for the design and construction of new POM-based frameworks with particular functions in the near future.
李新雄, 程琳, 方伟慧, 杨国昱. 基于金属氧簇和铜-四氮唑配合物构建的空旷骨架:合成、结构及性能[J]. 化学学报, 2013, 71(02): 179-185.
Li Xinxiong, Cheng Lin, Fang Weihui, Yang Guoyu. A Series of Open-Frameworks Constructed From Polyoxoanion Clusters and Copper-tetrazolate Complexes: Synthesis, Structure and Properties. Acta Chimica Sinica, 2013, 71(02): 179-185.