SURFACE ORGANOMETALLIC CHEMISTRY OF TIN - FORMATION AND DYNAMIC BEHAVIOR OF WELL-DEFINED SI-O-SNR(3) (R=CYCLOHEXYL, PHENYL) SURFACE FRAGMENTS ON SILICA - AN NMR AND INFRARED STUDY

Reaction of SnR(4), (R = cyclohexyl, phenyl) with silica dehydroxylate d at 200 or 500 degrees C leads to the well-defined species drop Si-O- SnR(3) which have been characterized by analytical methods and C-13 CP -MAS and Sn-119 MAS NMR spectroscopies. It was deduced from C-13 NMR d ata that, in the grafted entities, the phenyl group probably rotates f reely around the Sn-C bond. The phenyl group is not bonded to the surf ace by van der Waals contacts, in contrast to the cyclohexyl group.