Design, synthesis and evaluation of multifunctional dithienothiophene monomers, dimers and trimers

Inspired by the color tuning of carotenoids pigments in lobster, our group highlighted how the interplay of chromophore polarization and planarization is the key point for the design of environment sensitive fluorescent probes, named “flippers”. They are constituted by an electron rich DTT (dithieno[3,2-b;20,30-d]thiophene) moiety connected through a bond to an electron poor DTT-S,S-dioxide to achieve a fully operative push-pull system. A polar head group is linked to the hydrophobic core to ensure right orientation inside the lipid membrane. Sensitivity comes from the ability to adopt a twisted or planar conformation in response to the packing of the environment. The difference observed in excitation spectrum of the two conformation can be used to detect and study membrane tension. To screen the effect of further chemical modifications, chromophore length and oxidation, steric hindrance and extended conjugation are the main factors that can be evaluated in order to affect the spectroscopic properties of these powerful probes