1. Synthesis and Development of Novel Bis-Siloxy Arenes for Functionalized Magnetic Nanoparticles
David A. Spivak, Department of Chemistry, Louisiana State University
Currently, an important topic in technology and engineering is how to graft organic compounds to metal oxides such as silicon-oxides (“window glass”), titanium oxides, or magnetite (iron oxide). Coatings on glass or titanium oxide are often immobilized via covalent siloxane linkages, and we are investigating these conjugation groups for magnetite.
Metal oxide coatings covalently bonded via a siloxane group can degrade once the covalent bond is broken, even though bond breakage is reversible. All siloxane coated materials have only a single conjugating bond and thus risk degradation by siloxane bond cleavage. However, if there were 2 siloxane bonds significantly greater stabilization would occur as a result of the chelation effect, where if one bond breaks the coating is held in place by the second bond and eventually the first bond can reform. This prediction for mono- versus bis-siloxy benzenes was studied and presented in part one of the “Results and Discussion” section. Once stability parameters have been determined, part 2 of this study is to synthesize a chloromethyl benzene substituted with the most stable siloxane derivative. Part 3 will be the expansion of the functionalized benzene to longer conjugating chains forming long-tethered bis-alkyl-siloxy arene coatings to optimize coverage by reducing steric strain at the grafting surface.
Outline of approaches for testing the stability of mono and bis-siloxy benzenes.