SURFACE ORGANOMETALLIC CHEMISTRY OF TIN - FORMATION OF THE GRAFTED ORGANOMETALLIC COMPLEX (-]SI-O)2SN(N-C4H9)2 BY REACTION OF H2SN(N-C4H9)2 WITH THE SURFACE OF A PARTIALLY DEHYDROXYLATED SILICA

Reaction of H2Sn(n-C4H9)2 with the surface of Aerosil silica dehydroxylated at 200 or 500-degrees-C was followed by surface microanalysis, quantitative analysis of the evolved gases, C-13 CP-MAS NMR, and infrared spectroscopy. At room temperature after a short period of interaction, the starting complex is simply physisorbed on the silica surface. Two types of weak interactions occur between surface silanols and both the CH groups of the butyl ligands and the tin hydride(s). For longer periods of interaction and/or higher temperature, a well-defined surface species (greater-than-or-equal-to Si-O)2SnBu2 (2) is formed on both types of silica. The infrared and C-13 CP-MAS data are consistent with a hydrogen-bonding interaction between surface butyl ligands and surface silanols. Possible formation of (greater-than-or-equal-to Si-O)Sn(H)Bu2 as an intermediate in the formation of 2 is discussed.