Reversible Photochemical Modifications in Dicarbene‐Derived Metallacycles with Coumarin Pendants |
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| Authors: | Prof. Ying‐Feng Han Prof. Guo‐Xin Jin Constantin G. Daniliuc Prof. F. Ekkehardt Hahn |
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| Affiliation: | 1. Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Department of Chemistry, Fudan University, 220 Handan Road, 200433 Shanghai (P.R. China);2. Institut für Anorganische und Analytische Chemie, Westf?lische Wilhelms‐Universit?t Münster, Corrensstra?e 30, 48149 Münster (Germany);3. Organische‐Chemisches Institut, Westf?lische Wilhelms‐Universit?t Münster (Germany) |
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| Abstract: | Molecular rectangles were obtained from two bis(NHC) ligands, each featuring two terminal coumarin groups and two Ag+, Au+, or Cu+ ions. Upon UV irradiation (λ=365 nm), the dinuclear complexes undergo photochemical modification through a [2+2] cycloaddition reaction of two adjacent coumarin moieties to give a macrocyclic tetra(NHC) ligand. The photodimerization of the coumarin pendants proceeds stereoselectively to give the syn‐head‐head isomers in all cases. Subsequent irradiation at λ=254 nm initiates a photocleavage reaction with reconstitution of the initial dinuclear complexes with coumarin pendants. |
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| Keywords: | carbenes coumarin photochemical activation photodimerization supramolecular chemistry |
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