A photochemical mechanism was experimentally discovered and denoted proton-coupled energy transfer (PCEnT). A series of anthracene-phenol-pyridine triads formed the local excited anthracene state after light excitation at ca. 400 nm, which led to fluorescence around 550 nm from the phenol-pyridine unit. Direct excitation of phenol-pyridine would have required light around 330 nm, but the coupled proton transfer within the phenol-pyridine unit lowered its excited state energy so that it could accept excitation energy from anthracene. Singlet-singlet energy transfer thus occurred despite the lack of spectral overlap between the anthracene fluorescence and the phenol-pyridine absorption. Moreover, theoretical calculations indicated negligible charge transfer between the anthracene and phenol-pyridine units. PCEnT was suggested as an elementary reaction of possible relevance to biological systems and future photonic devices.

中文翻译：

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分子三联体中的质子耦合能量转移

通过实验发现了一种光化学机制，并将其命名为质子耦合能量转移（PCEnT）。一系列蒽-苯酚-吡啶三联体在大约 100°C 的光激发后形成局部激发的蒽态。400 nm，这导致苯酚-吡啶单元发出约 550 nm 的荧光。苯酚-吡啶的直接激发需要330 nm左右的光，但苯酚-吡啶单元内的耦合质子转移降低了其激发态能量，使其可以接受来自蒽的激发能。尽管蒽荧光和苯酚-吡啶吸收之间缺乏光谱重叠，但还是发生了单线态-单线态能量转移。此外，理论计算表明蒽和苯酚-吡啶单元之间的电荷转移可以忽略不计。PCEnT 被认为是一种可能与生物系统和未来光子器件相关的基本反应。