Synthesis and characterisation of heterobimetallic erbium alkoxides
1997 (English)Doctoral thesis, comprehensive summary (Other academic)
This thesis describes the synthesis and characterisation of alkoxides in the Er-M systems, where M = Al, Ti and Zr. The compounds found have been characterised by IR, UV-Vis DSC and single-crystal X-ray diffraction techniques and by chemical behaviour. It is shown that UV-Vis spectra can be used as an analytical tool to distinguish between different Er-containing alkoxides.
Two homometallic erbium isopropoxides have been synthesised. The first (1) is assumed to be a solvated non-oxo-alkoxide, which decomposes almost quantitatively to Er5O(OPri)13 when it is evaporated or partially hydrolysed. Er5O(OPri)13 can also be synthesised directly in high yields, using a reaction that involves partial hydrolysis. The reactivity of Er5O(OPri)13 is demonstrated by the reaction with Al4(OPri)12. The Nd analogues are also presented.
The structures of two different compounds in the Er-Al-isopropoxide system have been determined: Er2Al2(OPri)12(HOPri)2 and ErAl3(OPri)12, and a fourth[SGIW1] compound with the approximate Er-to-Al ratio 3:1 has also been found. ErAl3(OPri)12 could be syntesised using Er5O(OPri)13 as erbium source. This reaction was monitored by UV-Vis measurements and by IR studies of evaporated samples at different stages in the reaction. In the Er-Ti-ethoxide system only one compound could be isolated: Er2Ti4O2(OEt)18(HOEt)2, and partial hydrolysis was necessary in order to reach high yields. Synthesis under strictly anhydrous conditions produced only non-isolable compound(s). When using isopropanol in stead of ethanol, another oxo-alkoxide was formed: Er4TiO(OPri)13.
In the Er-Zr-isopropoxide system, the compound Er2Zr2O(OPri)12(HOPri)3 is obtained both under anhydrous conditions and after partial hydrolysis. No alkoxides with higher Zr content are formed in this system.
Most of the structural fragments, i.e. the M-O core structures (M = Er, Al, Ti and Zr) found in the different erbium-containing alkoxides, are rather common in both homometallic and heterometallic alkoxides. Examples of these fragments are: the square pyramidal M5O core, the C2h configuration (M4O62) and the "butterfly configuration" (M4O). Er2Al2(OPri)12(HOPri)2 is exceptional in containing the rarely seen linear arrangement of the M-O core.
Place, publisher, year, edition, pages
Stockholm: Department of Inorganic Chemistry, Stockholm University , 1997. , 104 p.
Research subject Inorganic Chemistry
IdentifiersURN: urn:nbn:se:su:diva-37002ISBN: 91-7153-681-7OAI: oai:DiVA.org:su-37002DiVA: diva2:291707
1998-01-16, Magnélisalen, KÖL, Frescati, Stockholm, 13:00 (English)
Galy, Jean, Professor
Härtill 6 uppsatser 2010-02-032010-02-032010-11-09Bibliographically approved