Synthesis of an azobenzene-linker-conjugate with tetrahedrical shape

The synthesis of a tripodal linker system with an adamantane core unit and an azobenzene headgroup is reported for the preparation of photochromic SAMs on gold surfaces. For the final Sonogashira-coupling of the ethynylene-linker precursor 4 with the p-iodo substituted azobenzene 6 model studies were required to optimize the coupling step in the presence of a diazene functionality. The photochromic properties of the photoswitch-linker-conjugate 1 were investigated in solution, and compared to the behavior of the precursor 6.