K. Folting, W. E. Streib, K. G. Caulton
1991
Citations
0
Influential Citations
73
Citations
Quality indicators
Journal
Polyhedron
Abstract
Abstract Aluminium isopropoxide, in the form of a crystalline solid of melting point 127°C, has been shown by X-ray diffraction to be a tetrameric molecular species of formula Al[(μ-OiPr)2Al(OiPr)2]3, consistent with earlier proposals and spectroscopic data. A central aluminium achieves coordination number six via two bridging alkoxide groups from each of three Al(OiPr)4− groups. The resulting planar Al(μ2-O)2Al rings have widened (∼ 132°) angles at oxygen to increase the non-bonded AlAl distance. While the terminal OiPr groups show the shortest (1.70 A) AlO distances in the molecule, they are nevertheless strongly bent (∼ 140°) at oxygen. The 1H NMR spectrum of Al4(OiPr)12 is analysed based on the structure reported here. Characterization of aluminosiloxane derivatives Al(OiPr)3-x(OSiMe3)x (x = 1−3) by 1H and 27Al NMR, mass spectrometry and IR spectroscopy is also reported. For x = 1 and 2, these show co-existence of several oligomers. The effect of incorporation of OSiMe3 groups is to favour smaller oligomers.