| Currently, synthetic routes to microporous materials such as zeolites and aluminophosphates are predominately hydrothermal methods, which provide little control over the final structure. There is a concerted effort by many to develop more fastidious pathways that would allow better control over the final product's structure and properties. In particular, pore dimensions of 10--15 A are highly desired because of their potential benefits in areas such as catalysis, adsorption, and molecular separations.; This dissertation summarizes results from an ongoing investigation of microporous metallophosphate synthesis via a molecular precursor approach. Research involved the synthesis of model compounds of common secondary building units (SBUs) found in group 13 metallophosphate materials, with primary targets being the four-ring (S4R) and double four-ring (D4R) SBUs.; Two syntheses are presented. In the first approach, tBu 3Al and tBu3Ga react with tert-butylphosphonic acid to form the tetrameric, D4R analogues [tBuMO3P tBu]4 (M = Al, Ga) through elimination of butane. For tBu3Ga reactions, other derivatives are possible through milder reaction conditions. Reaction at 0°C in pentane affords the cyclic dimer [tBu2GaO2PtBu(OH)] 2 while a trimeric structure [(tBuGa)2( tBu2Ga)(O3PtBu)2{lcub}O 2P(OH)tBu{rcub}] is isolated from refluxing toluene. For both the dimer and trimer, subsequent reaction with Me2NSiMe3 yields silylated derivatives [tBu2GaO2P tBu(OSiMe3)]2 and [(tBuGa) 2(tBu2Ga)(O3PtBu) 2{lcub}O2PtBu(OSiMe3){rcub}], respectively. There is an isomerization between the cis- and trans-isomers of the cyclic dimers, as observed from NMR spectroscopy. There is also evidence that both the cyclic dimers and tetramers fragment in solution, as suggested by mixing studies with similarly derivatized dimers and tetramers, respectively.; Similar reactions are also performed with phenylarsonic acid, giving the tetrameric [tBuAlO3AsPh]4 and the oxo-bridged dimer [tBu2GaO2AsPh] 2O. Additionally, in an effort to apply the butane elimination route to porous materials, tBu3Al is reacted with 4-cyanobenzylphosphonic acid to yield [tBuAlO3P(4-C6H4CN)] 4, which can potentially act as a multidentate ligand to form three-dimensional coordination networks.; Second, molecular aluminophosphates are prepared via a trimethylsilyl elimination route. Reacting tris(trimethylsilyl)phosphate with tBu2AlCl yields the cyclic dimer [t Bu2AlO2P(OSiMe3)2] 2, while a similar reaction with tBuAlCl2 yields the tetramer [tBuAlO3P(OSiMe3)] 4. Such compounds are potential precursors to solid-state materials. Analogous reactions with AlCl3 and GaCl3 gives the adducts, Cl3M·OP(OSiMe3)3 (M = Al, Ga).; The synthesis, characterization, and reactivity of these and related compounds are discussed. The majority of these compounds have been fully characterized by NMR, IR, mass spectrometry, elemental analysis, and X-ray crystallography. |
