Sysoiev D. Synthesis and investigation of photochromic switches based on diarylethenes and on azobenzenes

This thesis is devoted to the synthesis, investigation of photochromic properties of molecular switches based on diarylethenes and on azobenzenes. Condensation of bis(formyl)difurylethene with CH-acidic compounds and its reaction with thiosemicarbazide derivatives and phosphonium salts provided products with extended pi-system as practically applicable objects for molecular electronics. Thiomethyl-terminated azobenzene and its homologue were synthesized for mechanically controlled break-junction experiment in order to avoid the problem of mechanical sulphur-gold bond rupture when using the directly thiolated azobenzene. Cycloalkene ring contraction in the fluorinated cyclobutene-based molecular switches led to the remarkable enhancing of the cycloreversion quantum yield of the photochromic diarylethenes bearing pi-conjugated substituents. New isoxazole- and pyrazole-based diarylethenes were synthesized, and their photochromism was investigated in solution. Synthesized diarylethenes underwent previously unknown transformation induced by nucleophilic bases towards new seven-membered carbocycle derivatives.