The introduction of an ester group in the flavylium core allowed the reversible conversion between two different flavylium compounds each one exhibiting its own reaction network. An unidirectional switching cycle between 7-diethylamino-2-(4-(methoxy-carbonyl)phenyl)-1-benzopyrylium and 2-(4-carboxyphenyl)-7-diethylamino-1-benzopyrylium was achieved by means of alternate acid and base stimuli. Addition of base to a methanolic solution of the ester derivative gives rise to the trans-chalcone of the parent carboxylic acid, which upon acidification of the solution forms the respective flavylium cation. This species esterifies under very acidic conditions to restore the original methyl ester derivative. The chemical reaction networks of both compounds were fully characterized from their thermodynamic and kinetic aspects, by a series of pH jumps followed by UV-vis absorption and emission spectroscopy, stopped flow and H-down arrow NMR. The crystal structure of the trans-chalcone of the ester derivative was unveiled showing a supramolecular structure involving hydrogen bonding.
ISI Document Delivery No.: 874SITimes Cited: 1
Cited Reference Count: 20
Gago, Sandra Petrov, Vesselin Diniz, Ana M. Parola, A. Jorge Cunha-Silva, Luis Pina, Fernando
Cunha-Silva, Luis/A-8765-2012; Pina, Fernando/C-8161-2011; Gago, Sandra/H-5413-2012; Parola, A. Jorge/F-4048-2010; Diniz, Ana /C-6705-2013; Caparica, cqfb_staff/H-2611-2013; REQUIMTE, AL/H-9106-2013; Chaves, Pedro/K-1288-2013
Parola, A. Jorge/0000-0002-1333-9076;
Fundacao para a Ciencia e Tecnologia [PTDC/QUI-QUI/104129/2008, Pest-C/EQB/LA0006/2011]; [SFRH/BD/48226/2008]; [SFRH/BPD/18214/2004]
This work was supported by Fundacao para a Ciencia e Tecnologia through Projects PTDC/QUI-QUI/104129/2008 and Pest-C/EQB/LA0006/2011 and Grants SFRH/BD/48226/2008 (A.D.) and SFRH/BPD/18214/2004 (V.P.).
Amer chemical soc
Washington