Date of Award
Doctor of Philosophy
Craig Eliot Barnes
George K. Schweitzer, Mark D. Dadmun, Engin Serpersu
Three metallocene and half-sandwich Group 4 complexes of cuboctameric
spherosilicate (Si8O20(TiCp2Cl)8, Si8O20(ZrCp2Cl)8, and Si8O20(TiCp*Cl2)8) were successfully prepared by the exchange reaction of Group 4 metal chlorides with the spherosilicate starting material, Si8O20(SnMe3)8. These complexes were found to be catalytically active in olefin polymerization. Their preparative reactions clearly demonstrate a synthetically useful route towards many other derivatives of spherosilicate through the Si8O20(SnMe3)8 starting material. A new synthesis of the key precursor, octa(trimethyltin) cuboctameric spherosilicate Si8O20(SnMe3)8, was developed. It was found that most of the waters of hydration of the initial hydrate ([NMe4][Si8O20] @ n H2O, = 60! 70) could be removed by heating to 90 ! 100 °C. This “dehydrated” material proved to be synthetically useful and could be exhaustively silylated and stannylated in good to fair yields. The structures of Si8O20(SnMe3)8, Si8O20(SiMe3)8, and Si8O20(TiCp2Cl)8 are reported.
Saengkerdsub, Suree, "Group 4 Metallocene and Half-sandwich Derivatives of Spherosilicate: Preparation fromSi8O20(SnMe3)8 and Their Olefin Polymerization Activity. " PhD diss., University of Tennessee, 2002.