Revisiting Alkoxysilane Assembly on Silica Surfaces: Grafting versus Homo-Condensation in Solution.

Silica surface functionalization is often done through the condensation of functional silanes on silanols, silica surfaces' terminal groups. APTES, aminopropyltriethoxysilane, is widely used due to its assumed high reactivity with silanols, kinetically promoted by the catalytic action of the terminal amine function. Here, we revisit, based on a quantitative analysis by solid-state Si NMR, the assembly of this silane on silica surfaces to investigate whether its presence results from grafting, i.

MeSi(CH SnRO) (R=Ph, Me SiCH ): Building Blocks for Triangular-Shaped Diorganotin Oxide Macrocycles.

The syntheses of the novel silicon-bridged tris(tetraorganotin) compounds MeSi(CH SnPh R) (2, R=Ph; 5, R=Me SiCH ) and their halogen-substituted derivatives MeSi(CH SnPh I ) (3, n=1; 4, n=2) and MeSi(CH SnI R) (6, R=Me SiCH ) are reported. The reaction of compound 4 with di-t-butyltin oxide (t-Bu SnO) gives the oktokaideka-nuclear (18-nuclear) molecular diorganotin oxide [MeSi(CH SnPhO) ] (7) while the reaction of 6 with sodium hydroxide, NaOH, provides the trikonta-nuclear (30-nuclear) molecular diorganotin oxide [MeSi(CH SnRO) ] (8, R=Me SiCH ). Both 7 and 8 show belt-like ladder-type macrocyclic structures and are by far the biggest molecular diorganotin oxides reported to date.