Insights into the photoinduced anion translocation of donor-π-acceptor (ion) molecules.

By strategic design and synthesis of a new series of phosphonium salts (compounds 1-7[OTf]), where [OTf] stands for the trifluoromethanesulfonate anion, we performed comprehensive spectroscopic and dynamic studies on the photoinduced anion migration in toluene. Our aim is to probe if the anion migration is associated with an intrinsic barrier or is barrier-free. After the occurrence of excited-state intramolecular charge transfer (ESICT) in 1-7, the charge redistribution of the cation triggers the translocation of the counter anion [OTf], resulting in emission spectral temporal evolution.

The indanone N-H type excited-state intramolecular proton transfer (ESIPT); the observation of a mechanically induced ESIPT reaction.

We report the design and synthesis of indanone derivatives 1-4 with RR'N-H⋯OC intramolecular hydrogen bonds, in which ESIPT takes place and its dynamics and thermodynamics correlate with H-bond strength, facilitated by electron-withdrawing R' groups. Compound 4 (R' = COCF) shows mechanically induced ESIPT for the first time, where -CF⋯HN- interaction plays a key role in the non-centrosymmetric crystal packing.

Multiple Enol-Keto Isomerization and Excited-State Unidirectional Intramolecular Proton Transfer Generate Intense, Narrowband Red OLEDs.

A novel series of excited-state intramolecular proton transfer (ESIPT) emitters, namely, , , and , endowed with dual intramolecular hydrogen bonds, were designed and synthesized. In the condensed phase, exhibit unmatched absorption and emission spectral features, where the minor 0-0 absorption peak becomes a major one in the emission. Detailed spectroscopic and dynamic approaches conclude fast ground-state equilibrium among enol-enol (EE), enol-keto (EK), and keto-keto (KK) isomers.