Preparation and photoreaction of organogels based on benzophenone

In this paper, first photoreactive low-molecular weight organogels are described. Benzophenone derivatives functionalised with two long alkylamides 1a–c were designed and synthesized as photoreactive gelator molecules. The compounds formed organogels in several hydrogen donor solvents, e.g. 2-propanol and 1,3,5-triisopropylbenzene. Microstructures of the gels by scanning electron microscopy (SEM) revealed a 3D fibrous network and spherical aggregation. Compound 4 based on isopropylbenzene having an octadecylamide, which was designed as a photochemical hydrogen donor molecule, occurred gelation in a variety of organic solvents. In the case of a 1:1 mixture of 1c and 4 in several solvents, each component independently caused gelation to give a simple mixture of different gels. Irradiation of the gel of 1a in 2-propanol decomposed gradually the gel into solution to give pinacol as a main product. Similarly, photoreaction of the 1:1 two-component gel of 1c and 4 in benzene afforded corresponding pinacol.