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Synthesis and characterization of organo-borate solids

Authors Au Yeung, Siu Fung
Issue Date 2011
Summary Boric acid ‘flux’ synthesis was developed by our group and assisted the preparation of new borate materials solids. In this thesis apply the methodology to the preparation of new organo-borate materials. Some background and motivation for this work is presented in Chapter 1. In Chapter 2 we describe some novel phases of organoborate phases including [(C4H10N2)(B6O10H2)] with direct B-N connection. The flux approach also led to the formation of a number of organic salts of polyborate anions. In Chapter 3 metal and organic bis(salicylato) spiroborates have been synthesized with high yield, purity and crystallinity by the flux approach. Since salicylate and its derivatives are asymmetric chelates, the boron centers are chiral. Resolution of the [BS(Sal)2] anion was effected by using quininium as chiral counter cation. In aqueous media the chiral B center was found to be labile, the rate of scrambling t1/2 is about 40mins. However. solutions of chirally resolved B(Sal)2 ions have been found to be indefinitely stable in DMF solution at room temperature. In Chapter 4 hydrothermal boric acid ‘flux’ and solvothermal synthesis of tartratoborates affords simple monomer, cyclic oligomer or chain polymer arrangements. For L-tartrate all three types can be isolated through use of different crystallization conditions, such as solvent, temperature, reagent stoichiometry and the identity of the counter cations. For meso-tartrate two isomeric cyclic tetramers can be fored using K or Na counter ions, that appear to exhibit a templating effect. Nmr shows that the rings are stable in solution. Finally in Chapter 5 we looked at metal-organic framework (MOF) formation using calcium and group 13 elements. The study of calcium tartrate phases was due to the unintended preparation of these from boric acid flux reactions. In the indium system interesting phase types were formed including a porous MOF polymer.
Note Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2011
Language English
Format Thesis
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