New polynuclear aluminium oxoalkoxides. Crystal structures of [Al5(µ5-O)(µ-OBui)8(OBui)5] and [Al8(µ4-O)2(µ-OH)2(µ-OBui)10(OBui)8]
- 20 December 2001
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in J. Chem. Soc., Dalton Trans.
- No. 2,p. 259-266
- https://doi.org/10.1039/b105876m
Abstract
Treatment of [Al4(μ4-O)(OBui)10(BuiOH)] 1 with 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in boiling toluene produced [Al5(μ5-O)(μ-OBui)8(OBui)5] 2, whereas removal of BuiOH from 1 by azeotropic fractional distillation with toluene gave [Al8(μ4-O)2(μ-OH)2(μ-OBui)10(OBui)8] 3. X-Ray crystallography revealed that in 2 the μ5-oxo atom is bonded to one apical six-coordinated Al and four basal five-coordinated Al atoms, whilst in 3 the centrosymmetrical molecule comprises two tetranuclear fragments each containing a μ4-oxo atom bonded to five-coordinated Al atoms and bridged by two μ-hydroxo ligands. Alcohol exchange of 2 with BunOH gave [Al5(μ5-O)(μ-OBui)8(OBui)4(OBun)] 4 and of 1 with CF3CH2OH gave [Al4(μ4-O)(OBui)6(OCH2CF3)4(CF3CH2OH)] 6. Other compounds synthesised were [Al4(OCH2CF3)12] 7, [Al4(μ4-O)(OCH2CF3)10(CF3CH2OH)] 8, [Al{OCH(CF3)2}3(THF)] 9, and [Al{OCH(CF3)2}3(Et2O)] 10. Using 17O enriched (10%) water, samples of 1–4, 6 and 8 labelled at the oxo atom were prepared and their 17O chemical shifts measured in addition to 1H and 27Al NMR chemical shifts. Possible reaction pathways for the formation of 2 and 3 from 1 are discussed. Structural aspects of aluminium oxoalkoxides are discussed.Keywords
This publication has 0 references indexed in Scilit: