title: Modification of different zirconium propoxide precursors by diethanolamine. Is there a shelf stability issue for sol-gel applications?
abstract: 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.
authors.affiliation: 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.
authors.forename: Gerald I
authors.initials: GI
authors.lastname: Spijksma
authors.affiliation: 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.
authors.forename: Dave H A
authors.initials: DHA
authors.lastname: Blank
authors.affiliation: 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.
authors.forename: Henny J M
authors.initials: HJM
authors.lastname: Bouwmeester
authors.affiliation: Department of Chemistry, SLU, Box 7015, 75007 Uppsala, Sweden.
authors.forename: Vadim G
authors.initials: VG
authors.lastname: Kessler
mesh_terms: D056831:Coordination Complexes / Q000138:chemical synthesis / Q000737:chemistry; D018360:Crystallography, X-Ray; D004983:Ethanolamines / Q000737:chemistry*; D005782:Gels / Q000737:chemistry*; D006868:Hydrolysis; D008968:Molecular Conformation; D015040:Zirconium / Q000737:chemistry*
chemical_list: D056831:Coordination Complexes; D004983:Ethanolamines; D005782:Gels; C020283:diethanolamine; D015040:Zirconium