One-pot reaction approach to the synthesis of dihydropyrimido-diindole fluorophores (DPDI) was developed. In DPDI molecules, the two pyrrole rings in dipyrromethane were bridged by a carbon atom, eliciting a six-membered ring and rigid planar structure. Photophysical measurements demonstrated that DPDI can exhibit strong fluorescence, large Stokes shift and low sensitivity to pH. Cyclic voltamogram indicated a pair of redox peaks of DPDI near ±0.48V, implying that DPDI can be oxidized by nitrite (NO₂⁻). In the presence of NO₂⁻, DPDI showed apparent change in colours and fluorescence intensity owing to the implantation of NO₂⁻. From this basis, a highly sensitive and selective analysis of NO₂⁻ was established using DPDI as probes, which offered a sensitive determination of NO₂⁻ in the concentration range of 0–17 μM with the detection limit of 2.2 nM. Furthermore, DPDI was employed for fluorescence imaging, demonstrating the ability to discriminate from different concentrations of NO₂⁻ in living cells. The newly developed DPDI dyes showed the obvious advantages of facile preparation and large Stokes shift over conventional dipyrrole-based phosphors.

开发了一锅法合成二氢嘧啶-二吲哚荧光团（DPDI）。在DPDI分子中，二吡咯甲烷中的两个吡咯环被碳原子桥接，从而形成六元环和刚性平面结构。光物理测量表明，DPDI可以显示强荧光，大斯托克斯频移和对pH的低敏感性。环状伏安图表明一对接近±0.48V DPDI的氧化还原峰，这意味着DPDI可以通过亚硝酸盐被氧化（NO ₂ ^- ）。在NO的情况下₂ ^-，DPDI显示出由于NO的植入颜色和荧光强度明显变化₂ ^- 。从这个基础上，NO的高灵敏度和选择性分析₂ ^-使用DPDI作为探针，其提供NO的敏感判定成立₂ ^-在0-17μM的浓度范围内具有2.2纳米的检测极限。此外，DPDI被用于荧光成像，显示出从不同浓度的NO以辨别能力₂ ^-在活细胞。新开发的DPDI染料与传统的基于二吡咯的荧光粉相比，具有制备方便，斯托克斯位移大的明显优势。