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.
Int J Mol Sci. 2009 Nov 13;10(11):4977-4989. doi: 10.3390/ijms10114977.
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) with (1/2) a mol equivalent of H(2)dea the complexes Zr(2)(O(n)Pr)(6)(OCH(2)CH(2))(2)NH (1) and Zr(2)(O(n)Pr)(2)(O(i)Pr)(4)(OCH(2)CH(2))(2)NH (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)(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.
研究了不同的正丙氧基锆前体与 H(2)dea 的改性，通过分离的改性物种的表征进行了研究。用（1/2）摩尔当量的 H(2)dea 改性正丙氧基锆和Zr(O(n)Pr)(O(i)Pr)(3)((i)PrOH)，得到了Zr(2)(O(n)Pr)(6)(OCH(2)CH(2))(2)NH（1）和Zr(2)(O(n)Pr)(2)(O(i)Pr)(4)(OCH(2)CH(2))(2)NH（2）这两种四核配合物。然而，这些四核化合物的 1H-NMR 研究表明，无论是在溶液中还是在固体形式下，它们都不是时间稳定的。这种时间不稳定性对材料性能的影响通过光散射和 TEM 实验得到了证明。用（1/2）或 1 当量摩尔的 H(2)dea 改性异丙氧基锆，会形成三核配合物 Zr{eta(3)mu(2)-NH(C(2)H(4)O)(2)}(3)Zr(O(i)Pr)(3)(iPrOH)(2)（3），抗衡独特的非配位中心锆原子。这种配合物 3 是第一批被证明在溶液中长时间稳定的改性锆丙氧基前体之一。溶胶-凝胶合成产物的粒径和形态强烈依赖于前体溶液的时间因素和最终热处理。可重复的溶胶-凝胶合成需要使用稳定的溶液前体。
