Synthesis and structure of functional spherosilicate building block molecules for materials synthesis

Abstract

Cubic, trialkyl tin functionalized spherosilicates Si 8O 20(SnR 3) 8 (R = Me, n Bu) and the pentagonal prismatic tin-spherosilicate Si 10O 25(SnMe 3) 10 have been synthesized and characterized. Single crystal X-ray structures were obtained for Si 8O 20(SnMe 3) 8 ( I), Si 8O 20(SnMe 3) 8 · 4H 2O ( I · 4H 2 O), and Si 10O 25(SnMe 3) 10 · 4H 2O ( II). Structural metrics for the silicate cores observed in these structures were compared to other Si 8O 12 and Si 10O 25 cores reported in the CSD database. A pronounced tetragonal distortion of the Si 8O 20 cage leads to Si–O–Si bond angles that are considerably distorted in I · 4H 2 O when compared to other analogous Si 8O 12 structures described in the literature. These octameric stannylated spherosilicates readily react with metal chlorides to produce mesocopically interesting metal oxide and hybrid materials. An illustration of this is found in the reaction of the octameric anhydrous tin compound I with titanocene dichloride to give the octatitanocene derivative Si 8O 20(Cp 2TiCl) 8 · 3CH 2Cl 2 ( III). The single crystal structure of III is also described.