Project C3

NMR Control of Light Induced Conformation Switching

Prof. Dr. rer. nat. G. Buntkowsky

Physical Chemistry of Condenseal Matter
Eduart-Zintl-Institut für Anorganische & Physikalische Chemie
TU Darmstadt – Fachbereich Chemie
L2|02 52
Petersenstr. 22
64287 Darmstadt
Tel.: +49 6151 16-2607

Novel mesoporous silica materials functionalized with optical switchable groups have a large application potential as nano-catalysts, nano-filters, nano-valves or controllable adsorbents. Owing to their production process they have well-defined pore diameters and are size selective. Azobenzene is employed as building block for the optical switching of the desired function. Ligand R1 of the azobenzene symbolizes the switchable function. It will be grafted by a linker group to the surface (see Figure 1) resulting in an optical switchable composite. The project focuses on the switching of catalytically active groups[6] and hydrogen bond donors or acceptors. The optical switching enables or disables these functions by turning these groups either towards the pore center (ON) or towards the pore surface (OFF). The efficiency and kinetics of the optical switching is monitored by multi-nuclear high resolution solid state MAS-NMR spectroscopy. The torsion angle dependence of the chemical shift and the strength of magnetic dipolar interactions are employed as spectroscopic observables which monitor the switching.