Effect of electron-donating groups on the excited state spectroscopy and dynamics of 2′-hydroxychalcone derivatives

Abstract

We investigated the effect of different electron-donating groups on the intramolecular charge transfer (ICT) process in three hydroxychalcone derivatives. More efficient ICT was observed when replacing N(Me)2 by pyrrolidine due to less hydrogen bonding with solvent. Adding NH2 to the structure caused more planarity that was detected as a larger fluorescence quantum yield and narrower fluorescence peak. This was confirmed by femtosecond transient absorption in which the intramolecular twisting process, observed in the other derivatives, was absent in the presence of NH2. This work should be a useful step toward understanding and tailoring the excited state spectroscopy of chalcone derivatives.