SYNTHESIS AND OPTICAL-PROPERTIES OF TERMINALLY SUBSTITUTED CONJUGATED POLYENES WITH BICYCLO[2.2.2]OCTANE AS SPACER

The conjugated polyenes 10, 11, and 17 respectively, with 9-anthryl- and 2-tetraphenylporphyrinyl (TPP) terminal groups and a bicyclooctane unit incorporated into the polyene chain were synthesized by Wittig olefinations. In all cases it was possible to obtain the all-(E) compounds from the (E)/(Z)-isomeric mixtures by chromatographic purification and several recrystallizations. From the UV/Vis spectra the separation of the TPP group and the polyene chain in 10, 11, and 17 can be deduced whereas in 10 and 11 the two conjugated double bonds are amalgamated into the anthryl group. In 17 the anthryl group is electronically separated from the polyene chain, and a selective excitation therefore is possible.