Photochemie von Acylaziden. III. Direkte und sensibilisierte Photolyse von p‐Trimethylsilylbenzoylazid in fluider Phase und in polymeren Schichten

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Abstract
Photochemistry of Acylazides. III. Direct and Sensitized Photolysis of p‐Trimethylsilylbenzoylazide in the Fluid Phase and in Polymeric LayersThe photochemistry of the title compound in cyclohexane was investigated by direct and sensitized excitation, respectively. The only products which could be detected by means of HPLC were the rearrangement product isocyanate from the singlet azide and the insertion product into the solvent via the singlet nitrene, respectively. Products via the triplet states were not formed by direct photolysis. The generally high quantum yields of the photolysis of the acylazide 1 are strongly dependent on the concentration. At 0.1 M the quantum yield amounts to 4.The photolysis was sensitized by several triplet generators creating the abstraction products as main products. But also insertion products were formed via the triplet azide. From the results a triplet ground state of the nitrene is postulated. The sensitization can be realized also by electron donors like diphenylanthracene, pyrene or perylene. An electron transfer to 1 is assumed. The products of this sensitization are the same as via the direct photolysis.The results in solutions can be applied to polymers. The modification of polymers (silylation by the nitrene formed) is possible in this way.