title: Using Time-Dependent Density Functional Theory to Probe the Nature of Donor-Acceptor Stenhouse Adduct Photochromes.
abstract: We present the first theoretical investigation of a recently proposed class of photochromes, namely donor-acceptor Stenhouse adduct (DASA) switches [J. Am. Chem. Soc. 2014, 136, 8169-8172]. By using density functional theory and its time-dependent counterpart, we investigate the ground- and excited-state structures, electronic transition energies, and several properties of the two isomeric forms. In addition to demonstrating that the selected level of theory is able to reproduce the main experimental facts, we show that 1) the two forms of the DASA photochromes are close to isoenergetic; 2) the two isomers possess similar total dipole moments, in spite of their very different sizes; 3) both isomers have a zwitterionic nature; 4) the nature of the dipole-allowed electronic excited state is vastly different in the two forms; and 5) the specific band shape of the extended DASA can be reproduced by vibronic calculations.
authors: CEISAM, UMR CNRS 6230, BP 92208, Université de Nantes, 2, Rue de la Houssinière, 44322, Nantes, Cedex 3, France.
authors: Adèle D
authors: AD
authors: Laurent
authors: Department of Chemistry, Faculty of Natural Sciences, Matej Bel University, Tajovského 40, SK-97400, Banská Bystrica, Slovak Republic.
authors: Miroslav
authors: M
authors: Medveď
authors: CEISAM, UMR CNRS 6230, BP 92208, Université de Nantes, 2, Rue de la Houssinière, 44322, Nantes, Cedex 3, France. Denis.Jacquemin@univ-nantes.fr.|Institut Universitaire de France, 103 bd St Michel, 75005, Paris Cedex 5, France. Denis.Jacquemin@univ-nantes.fr.
authors: Denis
authors: D
authors: Jacquemin
keywords: band shapes; density functional calculations; excited states; molecular devices; photochromism