Pentacoordination versus tetracoordination in silicon derivatives of an O,N,O'-tridentate ligand.
Bis[2-(2-hydroxy-3-methoxybenzylideneamino)phenolato-kappaO]dimethylsilicon, C(30)H(30)N(2)O(6)Si, (II), was isolated from the reaction of 2-(2-hydroxy-3-methoxybenzylideneamino)phenol, (I), with dichlorodimethylsilane at 339 K. It consists of two ligand molecules and the Me(2)Si unit forming a dialkoxydimethylsilane with a tetracoordinate Si atom. [2-(3-Methoxy-2-oxidobenzylideneamino)phenolato-kappa(3)O,N,O']dimethylsilicon, C(16)H(17)NO(3)Si, (III), was isolated from the same reaction conducted at 263 K. In this complex, the dianion of (I) is coordinated via two O atoms and an azomethine N atom to the pentacoordinate Si atom. According to quantum chemical calculations, (II) is the thermodynamically stable product and (III) is the kinetically favoured product.
Böhme
Uwe
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Institut für Anorganische Chemie, Technische Universität Bergakademie Freiberg, Leipziger Strasse 29, 09596 Freiberg, Germany. uwe.boehme@chemie.tu-freiberg.de
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