Synthesis, x-ray structural analysis and photochemistry of novel syn-periplanar bis-azo-skeletons

Abstract Skeletons with syn-periplanar bis-azo-chromophoric units ( 8,18,19 ) have been synthesized ( 8 : transannular NN/NN-distances 2.939(2.999) A, interorbital angle ω = 154.3°, X-ray analysts). In no case azo/azo-photocycloaddition has been observed upon direct or sensitized excitation.