Our work on templated vanadium tellurites is currently focused on understanding how one can control composition, structure and symmetry of new compounds. We have synthesized a series of new compounds, the first of which was published in the summer of 2010 (Inorg. Chem. 2010, 49, 5167). This work included an analysis of charge density matching in a series of compounds synthesized from NaVTeO5. Electron localization functions were used to better understand the size, shape and orientation of the stereoactive lone pairs on each tellurite group. Work on this system continues, with explorations including a wide range of starting materials.
Gallium phosphates and sulfates are part of a very large family of gallium oxysalts that exhibit a great deal of structural and compositional diversity. Our work on this system is focused on both the creation of new noncentrosymmetric materials and the development of synthetic routes to new compositions. We have recently demonstrated the ability of chiral organic amines to impart noncentrosymmetry in two gallium phosphates (Inorg. Chem. 2009, 48, 11277).
Gallium sulfates differ from analogous phosphates is many ways, most notably in their water solubilities. In order to circumvent the rather high water solubilities of gallium sulfates, we developed a new synthetic route in which solutions are concentrated and crystals are grown over a day or two at 100 ºC. This enables the growth of high quality single crystals without requiring long evaporation steps. The resulting four compounds constitute the first reported templated gallium sulfates (Cryst. Growth Des. 2010, 10, 4656).
In previous years, our work was focused on the study of polyoxomolybdates. We have determined how one can control the structure of the inorganic component, influence product composition, investigated the role of the amine, studied fluoride incorporation, quantified the role of charge density matching between the cationic amines and anionic polyoxomolybdates and learned to direct crystallization to noncentrosymmetric space groups. This work has resulted in the synthesis and structural determination of approximately 45 compounds. We have developed a new method for the quantification of surface areas of complex inorganic structures using a geometrical decomposition method, from which charge density matching is clearly observed. In addition, we have used chiral organic amines to force crystallographic noncentrosymmetry in a series of polyoxomolybdates and sulfated molybdates. The second harmonic generation of each compound was measured to confirm the symmetry assignment.