Modification of different zirconium propoxide precursors by diethanolamine. Is there a shelf stability issue for sol-gel applications?

Autor: Spijksma GI; Inorganic Materials Science, Faculty of Science & Technology, and Mesa+ Research Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.; Department of Chemistry, SLU, Box 7015, 75007 Uppsala, Sweden., Blank DHA; Inorganic Materials Science, Faculty of Science & Technology, and Mesa+ Research Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands., Bouwmeester HJM; Inorganic Materials Science, Faculty of Science & Technology, and Mesa+ Research Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands., Kessler VG; Department of Chemistry, SLU, Box 7015, 75007 Uppsala, Sweden.
Jazyk: angličtina
Zdroj: International journal of molecular sciences [Int J Mol Sci] 2009 Nov 13; Vol. 10 (11), pp. 4977-4989. Date of Electronic Publication: 2009 Nov 13.
DOI: 10.3390/ijms10114977
Abstrakt: Modification of different zirconium propoxide precursors with H(2)dea was investigated by characterization of the isolated modified species. Upon modification of zirconium n-propoxide and [Zr(O(n)Pr)(O(i)Pr)(3)((i)PrOH)](2) with (1/2) a mol equivalent of H(2)dea the complexes [Zr(2)(O(n)Pr)(6)(OCH(2)CH(2))(2)NH](2) (1) and [Zr(2)(O(n)Pr)(2)(O(i)Pr)(4)(OCH(2)CH(2))(2)NH](2) (2) were obtained. However, (1)H-NMR studies of these tetranuclear compounds showed that these are not time-stable either in solution or solid form. The effect of this time instability on material properties is demonstrated by light scattering and TEM experiments. Modification of zirconium isopropoxide with either (1/2) or 1 equivalent mol of H(2)dea results in formation of the trinuclear complex, Zr{eta(3)mu(2)-NH(C(2)H(4)O)(2)}(3)[Zr(O(i)Pr)(3)](2)(iPrOH)(2) (3) countering a unique nona-coordinated central zirconium atom. This complex 3 is one of the first modified zirconium propoxide precursors shown to be stable in solution for long periods of time. The particle size and morphology of the products of sol-gel synthesis are strongly dependent on the time factor and eventual heat treatment of the precursor solution. Reproducible sol-gel synthesis requires the use of solution stable precursors.
Databáze: MEDLINE
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