作者:Jingjing Zhang、Syena Sarrafpour、Terry E. Haas、Peter Müller、Samuel W. Thomas
DOI:10.1039/c2jm16173g
日期:——
This paper describes a previously unreported class of sterically crowded tetracene derivatives that have both phenyl and ethynyl substituents. The steric crowding above and below the tetracene core prevents overlap between the extended π-systems of the acenes. Substituent effects cause these tetra-substituted tetracenes to have absorbance and fluorescence spectra red shifted from either disubstituted derivatives or rubrenes, such that they have spectra similar to diarylpentacenes, but with higher quantum yields of fluorescence and greater photostability. These new molecules also undergo cycloaddition reactions with 1O2, giving regioisomeric mixtures of endoperoxides, and in contrast to longer acenes, the ethynyl substituents show only a modest stabilizing effect to photooxidation. Ethynylated tetracenes also exhibited photochromism, with their endoperoxides undergoing cycloreversion to yield the acene starting material at room temperature in the dark.
本文描述了一类先前未报道的空间拥挤并四苯衍生物,它们同时具有苯基和乙炔基取代基。并四苯核心上方和下方的空间拥挤防止了并苯的扩展 π 系统之间的重叠。取代效应导致这些四取代并四苯的吸光度和荧光光谱从二取代衍生物或红荧烯红移,使得它们具有与二芳基并五苯相似的光谱,但具有更高的荧光量子产率和更高的光稳定性。这些新分子还与 1O2 发生环加成反应,产生内过氧化物的区域异构混合物,并且与较长的并苯相比,乙炔基取代基仅对光氧化表现出适度的稳定作用。乙炔化并四苯也表现出光致变色性,其内过氧化物在室温下在黑暗中发生环化反应以产生并苯起始材料。