Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    EXAFS study of zirconium alkoxides as precursors in the sol-gel process: II. The influence of the chemical modification (1995)
    Springer
    Journal of sol gel science and technology 5 (1995), S. 5-14 
    Details
    ISSN: 1573-4846
    Keywords: X-ray absorption ; zirconium alkoxides ; sol-gel process ; precursor ; chemical modification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract EXAFS studies of primary zirconium alkoxides Zr(OR)4 with OR = n-propoxide and n-butoxide, dissolved in their corresponding alcohols and chemically modified with acetylacetone (Hacac) and acetic acid (HOAc) in different molal ratios, are presented. The EXAFS-spectroscopic results, supported by FT-IR-studies, indicate a different chemical behavior of the complexing agents. In contrast to acetylacetone, the addition of acetic acid does not change the oligomeric structure of the zirconium alkoxides. Amazingly, the modification with acetic acid leads, in comparison to the pure compounds, to a shortened metal centre distance, whereas in the reaction with acetylacetone the Zr-Zr distance is not changed. With the determined distances and a rough quantitative inclusion of the coordination numbers it was possible to deduce detailed structure models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00486706
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    EXAFS study of zirconium alkoxides as precursor in the sol-gel process: I. Structure investigation of the pure alkoxides (1994)
    Springer
    Journal of sol gel science and technology 3 (1994), S. 91-99 
    Details
    ISSN: 1573-4846
    Keywords: X-ray absorption ; zirconium alkoxides ; sol-gel process ; precursor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The properties of materials obtained by sol-gel processing show a certain dependence on the type of metal alkoxide and the solvent. Some authors assumed that these effects are caused by the degree of oligomerization of the metal alkoxides and their solvation. In order to obtain information on the structure and molecular complexity of the metal alkoxide we performed an EXAFS study on primary zirconium alkoxides Zr(OR)4, with OR = n-propoxide and n-butoxide in solution of their parent alcohol. The EXAFS data for zirconium iso-propoxide have been used as a reference, because its solid state structure is known from X-ray analysis. The Zr-Zr correlations which were observed for all investigated systems provide evidence for an oligomeric structure. Because the analysis of the co-ordination spheres around the central Zr-atom revealed different Zr-O bond lengths, some of the formerly postulated structure models can be ruled out. We propose solvated dimers or trimers or mixtures of both species as possible structures of zirconium propoxide and zirconium butoxide in solution of their parent alcohol.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00486715
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...