Structural Effects on the Ground and Excited-state Properties of Photoswitchable Hydrogen-Bonding Receptors

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• 作者：Yann Molard ; Dario M. Bassani ; Jean-Pierre Desvergne ; Nina Moran ; James H. R. Tucker
• 刊名：Journal of Organic Chemistry
• 出版年：2006
• 出版时间：October 27, 2006
• 年：2006
• 卷：71
• 期：22
• 页码：8523 - 8531
• 全文大小：319K
• 年卷期：v.71,no.22(October 27, 2006)
• ISSN：1520-6904

文摘

The ground- and excited-state properties of a series of photochromic barbiturate receptors (N,N'-bis{6-[-(anthracen-9-yloxy)alkanoylamino]pyridin-2-yl}-5-t-butyl-isophthalamide, Tn), in which anthracenechromophores are tethered via (CH₂)_n (n = 1, 3-6) polymethylene linkers to the H-bond receptor moiety,are described. In these systems, the thermally reversible [4 + 4] photodimerization of the anthracenesyields macrocyclic receptors (TnC) that possess significantly reduced affinity toward barbital as comparedto their acyclic counterparts. The length of the tether not only determines the overall binding ability ofthe cyclized receptor but also has a profound influence on the photochemical and photophysical propertiesof the anthracene chromophores. The reduced mobility experienced by the covalently bound anthracenescontrols the reactivity of a fluorescent excimer that is proposed to be an intermediate in the photocyclizationprocess.