Tautomerization of Z and E isomers of dipolar isatin bipyridylhydrazone complexes with Zn(II) ions. Photochromism - ON/OFF switching

Zn(II) complexes using L-a and L-b were synthesized. The Z-isomers of studied complexes were isolated from the reaction mixture. The structure of these complexes was determined by NMR spectroscopy and X-ray diffraction analysis. The Z-isomers of complexes are present in two conformations. The change in hydrazo = azo equilibrium of the complexes is achieved by light-stimulated photoreaction. The phototautomerization is a reversible process. By changing the wavelength used to stimulate photoreaction, the change is achieved in the tautomeric reaction equilibrium state in the desired direction. The studied complexes have the characteristics of ON/OFF switches. It is possible to use UV-vis and fluorescence spectroscopy to clearly define ON and OFF states and to measure the response of signals induced by photostimulation.

Automated summary

Zn(II) complexes were synthesized using L-a and L-b, with the Z-isomers isolated from the reaction mixture. The structure of these complexes was determined by NMR spectroscopy and X-ray diffraction analysis. The Z-isomers of complexes can undergo changes in the hydrazo = azo equilibrium through light-stimulated photoreactions.