Synthesis,characterization and single crystal structure determination of aluminum alkoxydisilanolates: precursors for silica–alumina composite |
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Authors: | Mostafa M Amini Gholamhossein Mohammadnezhad Mehdi Mirzaee Hamid Reza Khavasi |
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Institution: | 1. Department of Chemistry, Shahid Beheshti University, G.C., Tehran 1983963113, Iran;2. Department of Chemistry, Shahrood University of Technology, Shahrood, Iran |
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Abstract: | Several novel aluminum alkoxydisilanolate complexes were prepared by reaction of triphenylsilanol with aluminum 2‐methoxyethoxide, aluminum 2‐ethoxyethoxide, aluminum sec‐butoxide and aluminum iso‐propoxide. All new complexes, (Ph3SiO)2Al(OR)]2 where R = CH2CH2OCH3 (1), CH2CH2OC2H5 (2), CH(CH3)CH2CH3 (3) and CH(CH3)2 (4)] were characterized by elemental analysis, mass spectrometry and infrared spectroscopy (IR), as well as 1H, 13C, 29Si and 27Al NMR spectroscopies. The solid‐state structures of the representative compound 2 and 4 were also verified by single‐crystal X‐ray analyses. Complexes 2 and 4 are dimers having distorted trigonal bipyramidal and tetrahedral coordination at the aluminum center, respectively. The 27Al NMR spectrum of compound 2 showed that the solid‐state structure of the complex was not retained in solution, and tetracoordinated aluminum was found in solution in contrast to the pentacoordinated geometry in the solid state. The hydrothermal treatment of 1 and 4 at 200 °C and the subsequent calcination at 1000 °C resulted in the formation of alumina–silica composite (4SiO2·Al2O3) with γ‐alumina in the silica matrix. Copyright © 2010 John Wiley & Sons, Ltd. |
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Keywords: | aluminum alkoxydisilanolate X‐ray crystal structure 27Al NMR composite |
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