Photochromism is the photoinduced reversible transformation between two isomers having different absorption spectra. This instant change of optical properties has attracted much attention, especially for its technological applications in optoelectronic devices, such as rewritable optical memories and switches [1]. Among various photochromic materials, diarylethenes with heterocyclic rings, as for instance (oligo)thiophenes, have proven to be thermally stable and fatigue-resistant [2]. In general, molecules confined in molecular containers behave differently from those in solution. For instance, they can display accelerated reaction kinetics, stabilized "reactive" intermediates, or enhanced catalytic properties [3]. Cucurbit[n]urils (CBn) are water-soluble macrocyclic receptors with high affinity and selectivity for guest molecules with appropriate size, shape, polarity and charge [4]. In particular, the structural and electronic properties of CBn make them excellent receptors for positively charged organic molecules, due to favorable interactions established between the carbonyl portals and cationic residues [5]. In this communication, we present a study on the influence of the supramolecular complexation of differently sized cucurbit[n]urils on the photoinduced ring-closure reaction of two symmetric dithienylethene derivatives bearing pyridinium moieties. The reaction dynamics has been followed by steady-state and time-resolved absorption and emission spectroscopy. The results have been rationalised by means of DFT and TD-DFT calculations. This work has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sk?odowska-Curie grant agreement No 734834 INFUSION. References: [1] Photochromic Materials: Preparation, Properties and Applications (Eds.: H. Tian, J. Zhang), Wiley-VCH, Germany, 2016. [2] M. Irie, T. Fukaminato, K. Matsuda, S. Kobatake, Chem. Rev., 2014, 114, 12174. [3] P. Ballester, M. Fujita, J. Rebek Jr., Chem. Soc. Rev., 2015, 44, 392. [4] S.J. Barrow, S. Kasera, M.J. Rowland, J. Barrio, O.A. Scherman, Chem. Rev., 2015, 115, 12320. [5] N. Basilio, J. Mendoza, S. Gago, A. J. Parola, Chem. Commun., 2017, 53, 6472.
Cyclisation reaction dynamics of a dithienylethene photoswitch in supramolecular host-guest complexes
A Barbieri;F Monti;B Ventura;N Armaroli;
2017
Abstract
Photochromism is the photoinduced reversible transformation between two isomers having different absorption spectra. This instant change of optical properties has attracted much attention, especially for its technological applications in optoelectronic devices, such as rewritable optical memories and switches [1]. Among various photochromic materials, diarylethenes with heterocyclic rings, as for instance (oligo)thiophenes, have proven to be thermally stable and fatigue-resistant [2]. In general, molecules confined in molecular containers behave differently from those in solution. For instance, they can display accelerated reaction kinetics, stabilized "reactive" intermediates, or enhanced catalytic properties [3]. Cucurbit[n]urils (CBn) are water-soluble macrocyclic receptors with high affinity and selectivity for guest molecules with appropriate size, shape, polarity and charge [4]. In particular, the structural and electronic properties of CBn make them excellent receptors for positively charged organic molecules, due to favorable interactions established between the carbonyl portals and cationic residues [5]. In this communication, we present a study on the influence of the supramolecular complexation of differently sized cucurbit[n]urils on the photoinduced ring-closure reaction of two symmetric dithienylethene derivatives bearing pyridinium moieties. The reaction dynamics has been followed by steady-state and time-resolved absorption and emission spectroscopy. The results have been rationalised by means of DFT and TD-DFT calculations. This work has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sk?odowska-Curie grant agreement No 734834 INFUSION. References: [1] Photochromic Materials: Preparation, Properties and Applications (Eds.: H. Tian, J. Zhang), Wiley-VCH, Germany, 2016. [2] M. Irie, T. Fukaminato, K. Matsuda, S. Kobatake, Chem. Rev., 2014, 114, 12174. [3] P. Ballester, M. Fujita, J. Rebek Jr., Chem. Soc. Rev., 2015, 44, 392. [4] S.J. Barrow, S. Kasera, M.J. Rowland, J. Barrio, O.A. Scherman, Chem. Rev., 2015, 115, 12320. [5] N. Basilio, J. Mendoza, S. Gago, A. J. Parola, Chem. Commun., 2017, 53, 6472.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
