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Molecules 2009, 14, 4838-4848; doi:10.3390/molecule OPEN ACCESS molecules ISSN 1420-3049 /journal/molecules Article Synthesis and Study of Novel Coumarin Derivatives Potentially Utilizable as Memory Media Radoslav Flašík, Henrieta Stankovičová *, Anton Gáplovský and Jana Donovalová Institute of Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská dolina CH-2, SK-842 15 Bratislava, Slovak Republic; E-Mails: rflasik@ (R.F.); gaplovsky@fns.uniba.sk (A.G.); donovalova@fns.uniba.sk (J.D.) * Author to whom correspondence should be addressed; E-Mail: stankovh@fns.uniba.sk; Tel.: +421-2 Fax: +421-2 Received: 22 October 2009; in revised form: 17 November 2009 / Accepted: 23 November 2009 / Published: 25 November 2009 Abstract: Novel coumarin derivatives, 2-oxo-2H-chromenecarbaldehyde hydrazones were prepared by reaction of substituted 2-oxo-2H-chromenecarbaldehydes with N-aminoimides in ethanol in the presence of 4-toluenesulfonic acid as catalyst. The photochromic and thermochromic properties of the prepared compounds were investigated. Keywords: chromenes; photochromism; thermochromism 1. Introduction Information technology has revolutionized daily life and the continuosly increasing amount of data to be stored and manipulated has strongly stimulated the search for switching and memory elements as tiny as a single molecule. Molecular switches can be converted from one state to another by an external stimulus such as light, temperature, electricity or a chemical reaction.