Novel Clusters of Transition Metals and Main Group Oxides in the Alkylamine/Oxovanadium/Borate System

摘要

Hydrothermal synthesis is an area of rapidly increasing importance for the synthesis of new and structurally complex, hybrid, organic-inorganic, solid-state compounds. Utilizing the ability of polar organic molecules to direct the crystallization of inorganic frameworks by incorporation in a geometrically specific manner through multipoint hydrogen bonding, we have been able to prepare several new classes of materials. Pre-synthesized organic molecules were used to imprint structural information ontoinorganic oxide lattices, and microporous solids with the largest cavities and lowest framework densities known, lamellar transition metal oxides or phosphates with organic cations or coordination compounds between the layers, polyoxometalates linked bycoordination compounds into 2-D and 3-D solids, materials with interlaced 1-D organic and inorganic chains, and organically templated transition metal halides161 have all been made. Even polyoxometa-late metal species, including the unusual [H_(16)(VO_2)_(16)-(CH_3PO_3)_8]~(8-), have been synthesized by hydrothermal synthesis We report here the use of this technique for the synthesis of 1 and 2 (en = ethylenediamine), which represent a novel type of clusters of transition metals and main group oxides in the organic cation/vanadium/borate system and possess unprecedented structures. Although a large number of borate mineral structures are known, and substantial progress has been made in classifying and understanding their structures, synthetically prepared and structurally characterized examples are rare.