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Domino Insertion–Coupling Synthesis of Solid‐State Luminescent Propynylidene Indolones
Author(s) -
Schönhaber Jan,
D'Souza Daniel M.,
Glißmann Tobias,
Mayer Bernhard,
Janiak Christoph,
Rominger Frank,
Frank Walter,
Müller Thomas J. J.
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201802237
Subject(s) - chromophore , domino , chemistry , luminescence , ground state , electronic structure , density functional theory , photochemistry , computational chemistry , materials science , optoelectronics , organic chemistry , atomic physics , physics , catalysis
The compound class of 3‐arylpropynylidene indolones, key intermediates in consecutive three‐component syntheses of various indole‐based chromophores with peculiar emission characteristics, are readily synthesized by a domino insertion–coupling synthesis with an electronically diverse substitution pattern in moderate to excellent yields. The title compounds are formed in E / Z ‐ratios from 100:0 to 0:100. Besides structure elucidation by NMR‐spectroscopy and X‐ray structure analysis, DFT calculations have been employed to rationalize the observed stereoselectivity. The photophysical properties of 3‐arylpropynylidene indolones are characterized by intense, tunable, solid‐state emission of N‐substituted derivatives as quantified for drop‐cast films. The electronic ground state structure was corroborated by DFT and TD‐DFT calculations, showing that gradient‐corrected exchange and correlation PBE (Perdew–Burke–Ernzerhof) functionals can be successfully employed to correctly reproduce the observed absorption characteristics of merocyanine derivatives. The huge Stokes shifts strongly depend on the electronic substitution pattern as supported by Hammett–Taft correlations.