Eine alternative Synthese des Oligoalumosiloxans [Ph2SiO]8[Al(O)OH]4 und seiner Alkohol‐Addukte |
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Authors: | Michael Veith Prof Dr Dr hc Andreas Rammo Volker Huch |
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Institution: | Institut für Anorganische Chemie, Universit?t des Saarlandes, Postfach 15 11 50, 66041 Saarbrücken, Germany |
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Abstract: | The oligoalumosiloxanes {Ph2SiO]8Al(O)OH]4·2,5Et2O·HOtBu} ( 6 ) and {Ph2SiO]8Al(O)OH]4·2Et2O·2HOiPr} ( 7 ) have been obtained from the reaction of diphenylsilanediol with aluminium‐tri‐tert‐butoxide and aluminium‐tri‐iso‐propoxide in ethyl ether with reasonable yields. In a 1:1 molar mixture of toluene and the respective alcohol (iso‐propanol or tert‐butanol), the ethyl ether molecules in {Ph2SiO]8Al(O)OH]4·4Et2O}, in 6 or 7 can be completely displaced forming the compounds Ph2SiO]8Al(O)OH]4·4HOiPr ( 8 ) and Ph2SiO]8Al(O)OH]4·nHOtBu ( 9 ). Whereas 6 , 7 and 8 are crystalline, 9 is obtained as a viscous liquid. An X‐ray structure determination on {Ph2SiO]8Al(O)OH]4·3Et2O·HOtBu} reveals different bonding modes of the diethyl ether molecules to the oligoalumosiloxane compared to the tert‐butanol, which forms two hydrogen bonds (one to the OH‐group of the inner Al4(OH)4 cycle and one through the alcohol OH‐group to a Si–O–Al moiety. The alcohol adducts have been characterized in solution through 1H‐, 13C‐ and 29Si‐NMR and show dynamic equilibria between the oligoalumosiloxane Ph2SiO]8Al(O)OH]4 and the alcohol molecules. |
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Keywords: | Alumosiloxanes Oligoalumosiloxanes Silicon Polycycles X‐ray diffraction |
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