An Investigation of Group (IV) Alkoxides as Property Controlling Reagents in the Synthesis of Ceramic Materials

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Abstract
Chemical synthetic methodologies are frequently employed to fabricate ceramic materials. To assist in determining methods for control over the final properties of ceramic materials, we have begun an investigation of the basic chemistry of solgel precursor solutions for lead zirconate titanate (PZT) thin films. The reactions between “M(OCHMe2)4” (M = Ti, Zr) and acetic acid were monitored by 1H, 13C, 17O NMR, and X-ray crystallography. The results of this investigation, the complexes generated, (Ti6(OCHMe2)12(OAc)4O4 1 Ti6(OCHMe2)8(OAc)8O4 2), and the types of films produced are reported. The synthesis of novel Group (IV) metal alkoxide complexes has been undertaken to generate precursors for ceramic materials with the desired characteristics internalized. In an attempt to reduce hydrolysis, the formation of a variety of metallo-organic compounds containing the sterically bulky adamantan-1-ol ligand (AdamO-H) was studied. It was demonstrated that the OCHMe2 ligands of “M(OCHMe2)4” (M = Ti, Zr) were easily replaced with AdamO, forming compounds with the empirical formula “(AdamO) n M(OCHMe2)4-n ” (n = 1,2,3, or 4). Spin-cast deposited films of these compounds were not affected by ambient humidity and crystallize upon evaporation of the solvent. Another set of alkoxide ligands which has been investigated is a series of tridentate alkyl alkoxides: 1,1,1-tris(hydroxymethyl)ethane (THME-H3), 1,1,1-tris(hydroxymethyl)propane (THMP-H3), 1,3,5-cyclohexanetriol (CYHT-H3), and 2,2-bis(hydroxymethyl) proprionic acid (BHMP-H3). These ligands have been reacted with Group 4 metal alkoxides to form a variety of precursors that have been identified by spectroscopic and analytical methods. The THME and THMP ligated complexes are of the general formula (THMR)2MA4(OCHMe2)10 [R = E, M = Ti, 3, and Zr, 4; R = P, M = Ti, 5 and Zr]. Films of these compounds demonstrate reduced susceptibility to hydrolysis when compared to the standard starting materials Ti(OCHMe2)4 6, and [Zr(OCHMe2)4 . HOCHMe2]2 7.