Reversible Dimerization/Polymerization of a Janus Diradical Producing Labile CC Bonds and Giant Chromism
Abstract
En esta comunicación se presenta el estudio espectroscópico y téorico de la dimerización/oligomerización reversible de un birradical derivado de naftoditiofeno el cual en su forma monomérica presenta una intenso color azul mientras que al agregar se muestra incoloro, siendo éstas formas intercambiables gracias a la aplicación de estímulos débiles como presión o temperatura.
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Zing | Abstracts | Submission ! ! www.zingconferences.com 1 ! Reversible Dimerization/Polymerization of a Janus Diradical Producing Labile CC Bonds and Giant Chromism N. Yanaib, T. Morib, I. Osakab, L. Qiuc, Miriam Peña Álvareze, J. T. López Navarretea, M. Kerteszc, Carlos J. Gómez-Garcíad, K. Takimiyab, José L. Zafraa and J. Casadoa,* a, Department of Physical Chemistry, Faculty of Sciences, University of Malaga, 29071 Malaga, Spain ([email protected]) b, RIKEN-CEMS 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan c, Department of Chemistry, Georgetown University, Washington, D.C. 20057-1227, USA d, Instituto de Ciencia Molecular, Universidad de Valencia 46980 Paterna, Valencia, Spain e, Department of Physical Chemistry, Complutense University of Madrid, 28040 Madrid, Spain Multifunctional materials require of building blocks able to easily and reversibly tune their chemical structure in response to soft external stimuli. In this regard, chromism is a valuable property for functional materials often related to π-conjugated organic dyes in which alteration of the π-molecular structure gives rise to different electronic shapes before and after the color mutation. There are plenty of good examples of thermoand electro-chromic polymers, however, only a few cases based on small molecules, mainly related to mono-radicals. Even more uncommon examples are those related to diradicals, like phenalenyl based ones that forms stair-chain oligomers[1] or a tetrafluorobisimidazol diradical with a strong photochromism mediated by a double dimerization. [2] Figure 1. UV-Vis-NIR electronic absorption spectrum of monomer and σ-aggregates With this communication we present a spectroscopic and theoretical study of the reversible diradical σ-dimerization/polimerization of a new naphtodithiophene derivative, depending on different external mild conditions, that is accompanied by a strong chromism originated by the transition from quinoidal to aromatic cores during the process. References 1. A. Shimizu, T. Kubo, M. Uruichi, K. Yakushi, M. Nakano, K. Hirao, K. Matsumoto, H. Kurata, Y. Morita, K. Nakasuji, J. Am. Chem. Soc., 2010, 132, 14421. 2. A. Kikuchi, F. Iwahori, J. Abe, J. J. Am. Chem. Soc., 2004, 126, 6526.