1253299-45-4

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• 1253299-36-3 (E)-1-(4-methoxyphenyl)-2-{4-[(trimethylsilyl)ethynyl]phenyl}diazene 

Relevant academic research and scientific papers

Monitoring the reversible photoisomerization of an azobenzene-functionalized molecular triazatriangulene platform on Au(111) by IRRAS

Spectroscopic evidence of a reversible, photoinduced trans cis photoisomerization is provided for an azobenzene-functionalized triazatriangulene (TATA) platform on Au(111). As shown by scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS), these molecules form a well-ordered self-assembled monolayer (SAM) on Au(111). The surface-adsorbed azo-TATA platforms are also investigated by infrared reflection absorption spectroscopy (IRRAS); a methoxy marker group at the upper phenyl ring of the azo moiety is employed to monitor the switching state. The IRRAS data are analyzed by comparison with theoretical and transmission IR spectra as well as bulk and surface-enhanced Raman spectroscopic (SERS) data. IRRAS shows that the methoxy group is oriented perpendicular to the surface in trans- and tilted with respect to the surface normal in cis-configuration. This indicates that the photoswitching capability of the azobenzene moieties is retained on the gold surface. The lifetime of the cis-configuration is, however, reduced by a factor of ～103 with respect to the homogeneous solution.

Long-Distance Rate Acceleration by Bulk Gold

We report on a very unusual case of surface catalysis involving azobenzenes in contact with a Au(111) surface. A rate acceleration of the cis–trans isomerization on gold up to a factor of 1300 compared to solution is observed. By using carefully designed molecular frameworks, the electronic coupling to the surface can be systematically tuned. The isomerization kinetics of molecules with very weak coupling to the metal is similar to that found in solution. For their counterparts with strong coupling, the relaxation rate is shown to depend on the spin-density distribution in the triplet states of the molecules. This suggests that an intersystem crossing is involved in the relaxation process. Aside from their impact on catalytic processes, these effects could be used to trigger reactions over long distances.

Synthesis of functionalized triazatriangulenes for application in photo- Switchable self-assembled monolayers

Various triazatriangulenes are synthesized by nucleophilic attack at the central C atom of triazatriangulenium ions. The molecular functions, especially azobenzenes, are fixed via an ethynyl linker by in situ deprotection of trimethylsilylalkynes. The structure of two of these molecules is further investigated by X-ray crystallography. The photo-inducedtrans/cis-isomerization of the azobenzene substituted derivatives is analyzed in solution and shows great promise for the preparation of switchable functionalized monolayers, as the triazatriangulenes are known for their self-assembly on gold surfaces. [1].