Kannengießer, Jan-Falk

► Research

Stable aryl-substituted silanediols and -triols - properties, condensation behavior and application as precursors for polymers

Organosilanols, the silicon analogues of alcohols, are compounds with unique properties and diverse potential applications. Compared to alcohols, they are comparatively unstable and therefore condense easily, e.g. to polysiloxanes.

As part of the doctoral thesis, stable representatives of this class of compounds are to be synthesised, characterised and reacted. In order for the inherently unstable silanols to form stable molecules, a specific substitution pattern is required at the silicon atom, which requires a balance of steric and electronic influence. The various influences will be systematically investigated in the planned work. Special attention will be paid to aryl group-substituted compounds, as these substituents allow an increase in the molar refraction of the molecules, which offers an interesting aspect for the optical properties of the resulting condensation products. The synthesised silanediols and triols are extensively studied by different characterisation methods in order to obtain structure-property correlations and conclusions about the influence of the substituents on the silicon atom on silanol stability and reactivity. The obtained silanediols and silanetriols are also used as precursors for various siloxane-based materials, e.g. in thermal condensation for the synthesis of polysiloxanes and  silsesquioxanes. Apart from this, the silanols will also be used as ligands for metal alkoxides, which are used as precursors in the sol-gel process.