© 2019 Elsevier Ltd A novel tetracyanoruthenium(II) complex of formula K2[Ru(4,4″-azobpy)(CN)4], (1), with 4,4″-azobpy = 4,4″-azobis-(2,2′-bipyridine), has been synthesized and characterized by spectroscopic, electrochemical and photophysical techniques. The effects of reduction and protonation of the azo group of coordinated 4,4″-azobpy in the UV–Vis absorption and emission spectra of (1) were explored by spectroelectrochemical techniques and by addition of L-Cysteine. The behavior of (1) as a “molecular switch” could be explained with the aid of quantum–mechanical calculations by using density functional theory.
- L-Cysteine detection
- Molecular switches
- Proton-coupled electron transfer
- Ruthenium cyanides