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&z.dbd;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 3 ) shows mechanically induced ESIPT for the first time, where -CF 3 HN- interaction plays a key role in the non-centrosymmetric crystal packing. We designed and synthesized indanone derivatives with ESIPT, correlated to H-bond strength. Compound 4 shows mechanically induced ESIPT for the first time, with -CF 3 -HN- interactions crucial for non-centrosymmetric crystal packing.