Tetrazine-functionalized fluorogenic labels are pivotal in various scientific domains, but their fluorogenicity often diminishes when the emission wavelength extends into the near-infrared (NIR) region. This investigation confirms that photoinduced electron transfer (PET) is the primary mechanism causing fluorescence quenching in such NIR labels. Furthermore, we have discovered an unprecedented photoinduced charge centralization (PCC) within the conjugated frameworks of tetrazine-integrated fluorogenic dyes. These insights into the mechanisms of fluorescence quenching pave the way for advancing tetrazine chemistry at the photophysical level. Subsequently, we introduce a rational molecular design approach for crafting tetrazine-based NIR labels that leverages the PET mechanism to significantly boost their fluorogenic response.

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光诱导电子转移赋予基于四嗪的近红外标签的荧光性

四嗪功能化荧光标记在各个科学领域都至关重要，但当发射波长延伸到近红外 (NIR) 区域时，它们的荧光性通常会减弱。这项研究证实，光诱导电子转移 (PET) 是导致此类 NIR 标签中荧光猝灭的主要机制。此外，我们在四嗪集成荧光染料的共轭框架内发现了前所未有的光致电荷集中（PCC）。这些对荧光猝灭机制的见解为在光物理水平上推进四嗪化学铺平了道路。随后，我们介绍了一种合理的分子设计方法，用于制作基于四嗪的 NIR 标签，利用 PET 机制显着增强其荧光响应。