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Abstract: A new series of 4-benzofuranyl-N-alkyl-1,8-naphthalimides was prepared from 4-ethynyl-N-alkyl-1,8-naphthalimides and substituted o-iodophenols catalyzed by a Pd(PPh3)2Cl2/CuI system under mild conditions. The starting materials, 4-ethynyl-N-alkyl-1,8-naphthalimides, were synthesized with trimethylsilylacetylene by Sonogashira coupling reaction. The absorption and fluorescence spectra of these benzofuran-1,8-naphthalimides were recorded and the quantum yields were measured using quinine sulfate as the standard. The UV/vis absorption spectra were in the range of 380–400 nm and the emission spectra were in the range of 500–520 nm. [Copyright &y& Elsevier]

Abstract: A series of novel N-alkyl-1,8-naphthalimide derivatives with phenylacetylene at the C-4 position were synthesized using 4-bromo-1,8-naphthalimides and arylacetylenes as starting materials in the presence of Pd(PPh3)2Cl2/CuI under mild conditions. The absorption and fluorescence properties of these compounds were recorded and the quantum yields were measured in DMF solution using quinine sulphate as the standard. It was found that UV/vis absorption was in the range of 372–399nm and fluorescence emission was between 428 and 531nm. Substituent effects on absorption and fluorescence spectra are discussed. [Copyright &y& Elsevier]

A facile synthesis of styrylcoumarins based on Palladium-catalyzed reaction of coumarin diazonium salts with substituted styrenes is described. The reactions produced a series of 7-styrylcoumarins in good yields under mild conditions. The absorption and emission spectra of different styrylcoumarins were compared and discussed. Although the λa,max of the styrylcoumarins changed only slightly with a p-substituted styrene, the λe,max produced a blue shift which increased with the electron-withdrawing ability of the p-substituted group. The p-CH3 of styrylcoumarin caused a red shift of ca. 20 nm and also a higher fluorescence quantum yield. Styrylcoumarins with o, p-CN obtained well-resolved vibrational bands and the latter possessed higher fluorescence quantum yield. In addition, a coumarin extended at both the 3-positions with benzene and 7-position with p-chlorostyrene had better fluorescence properties. [Copyright &y& Elsevier]

A series of substituted stilbenylcoumarins were synthesized. The absorption-emission spectra were studied and the fluorescence quantum yields were determined. The covalent rigidification of stilbenylcoumarins produces a considerable enhancement of the fluorescence quantum yield compared to the open-chain analogs. To 3-(4-substitutedstilben-4-yl)-7-diethylaminocoumarin, the fluorescence quantum yield increases with the enhancement of the electron-withdrawing ability of the group at the 4′-position. In addition, 4′-Cl makes the stilbenylcoumarin produce strong fluorescence. [Copyright &y& Elsevier]