Molecular rotors: synthesis and evaluation as viscosity sensors

It has been shown that compounds containing the p-N,N-dialkylaminobenzylidene cyanoacetate motif can serve as fluorescent non-mechanical viscosity sensors. These compounds, referred to as molecular rotors, belong to a class of fluorescent probes that are known to form twisted intramolecular charge-transfer complexes in the excited state. In this study we present the synthesis and spectroscopic characterization of these compounds as viscosity sensors. The effects of the molecular structure and electronic density of these rotors to the emission wavelength, fluorescence intensity, and viscosity sensitivity are discussed.

Graphical abstractCompounds containing the p-N,N-dialkylaminobenzylidene cyanoacetate motif have a significant potential as fluorescent viscosity sensors. Here we evaluate the effects of the chemical structure and electronic density to the fluorescent properties of these rotors, including fluorescence intensity and viscosity sensitivity.Download full-size image