3-Piperazinyl propenylidene indolone merocyanines: consecutive three-component synthesis and electronic properties of solid-state luminophores with AIE propertiesDedicated to Professor Dr Dr. h. c. Lutz F. Tietze on the occasion of his 75th birthday.Electronic supplementary information (ESI) available: Preparation and analytical data of starting materials 1 and 3, 1H and 13C NMR spectra of compounds 4; solvatochromism data of compound 4a; Hammett correlations of compounds 4c-l; computed xyz coor

• Main Authors: Denißen, Melanie, Nirmalananthan, Nithiya, Behnke, Thomas, Hoffmann, Katrin, Resch-Genger, Ute, Müller, Thomas J. J
• Format: Article
• Language: English
• ISSN: 2052-1537
• DOI: 10.1039/c7qm00198c

A series of twelve 3-piperazinyl propenylidene indolone merocyanines was synthesized in a one-pot fashion using a consecutive three-component insertion-coupling-Michael addition sequence. Physical-organic treatment of the absorption data of a consanguineous series of this library allows semiquantitative Linear Free Energy Relationships (LFERs) to be established and confirmation of the positive absorption solvatochromicity. All Boc-substituted piperazinyl merocyanines display aggregation induced emission (AIE), which was corroborated for two solvent systems. In particular, crystallization-induced emission enhancement (CIEE) induced by ultrasonication could be shown for a model chromophore by confocal laser scanning microscopy (CLSM). One-pot insertion-coupling-addition synthesis gives piperazinyl indolones showing aggregation induced emission and crystallization-induced emission enhancement.