Radical-doped covalent organic frameworks (COFs) have received much interest as it confers additional functions such as photomodulated electrical conductivity, magnetism, and photochromism. Such COFs are relatively underexplored, however, mainly due to the lack of suitable highly photoactive building blocks. Herein, a rare radical-doped fully conjugated COF (PDI-COF) was rationally designed and prepared by incorporating photoactive perylenediimides (PDIs) into its framework. Characterization of the product PDI-COF not only confirmed its porous and stable skeleton, but also revealed the radical derived from photoinduced electron transfer between the PDI and electron donor. The fully conjugated and radical-doped characteristics enable the effective realization of near-infrared photothermal conversion in this COF. Moreover, this radical-doped COF can efficiently generate superoxide radical anions under light irradiation, which promote the photocatalytic C-3 thiocyanation of indoles and the oxidative coupling of amines in high yield and good recyclability at room temperature and without additives. This study demonstrates that introducing a photoactive organic dye into a COF is an effective approach to photothermal conversion materials and metal-free porous photocatalysts for application in photothermal therapy and photocatalytic organic synthesis.

中文翻译：

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用于近红外光热转换、吲哚 C-3 硫氰化和胺氧化偶联的完全共轭自由基掺杂 COF


自由基掺杂共价有机框架（COF）因其赋予光调制导电性、磁性和光致变色等附加功能而受到广泛关注。然而，这种 COF 的研究相对较少，主要是由于缺乏合适的高光活性结构单元。在此，通过将光活性苝二酰亚胺（PDI）纳入其框架中，合理设计并制备了一种罕见的自由基掺杂全共轭COF（PDI-COF）。产品PDI-COF的表征不仅证实了其多孔且稳定的骨架，而且揭示了PDI和电子供体之间光诱导电子转移产生的自由基。全共轭和自由基掺杂的特性使得该COF能够有效实现近红外光热转换。此外，这种自由基掺杂的COF在光照射下可以有效地产生超氧自由基阴离子，促进吲哚的光催化C-3硫氰化和胺的氧化偶联，在室温下且无需添加剂，收率高，可回收性好。这项研究表明，将光活性有机染料引入COF是光热转换材料和无金属多孔光催化剂用于光热治疗和光催化有机合成的有效方法。