Bartos Paulina, Szamweber Patrycja, Camargo Bruno, Pietrzak Anna, Kaszyński Piotr
Faculty of Chemistry, University of Lodz 91-403 Lodz Poland
Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences 90-363 Lodz Poland.
Chem Sci. 2025 May 27. doi: 10.1039/d5sc01182e.
Photocyclization of N-substituted carbazole derivatives of benzo[][1,2,4]triazine gave two carbazole-fused Blatter radicals with a novel heterocyclic skeleton. No photocyclization was observed for the analogous dibenzocarbazole, indole, benzimidazole, and phenoxazine precursors, which was rationalized with DFT computational methods. The two carbazole-derived radicals were characterized by spectroscopic (UV-vis, EPR) and electrochemical methods, while one of them was analyzed structurally (XRD) and magnetically (SQUID). The latter analysis revealed ferromagnetic interactions in the solid state with 2/ = 16.6 K. Properties of these first examples of a new class of stable radicals were analyzed with DFT methods, which confirmed significant impact of the -nitrogen atom on electronic properties and additional 15% spin delocalization.
苯并[][1,2,4]三嗪的N-取代咔唑衍生物的光环化反应生成了两个具有新型杂环骨架的咔唑稠合的布拉特自由基。对于类似的二苯并咔唑、吲哚、苯并咪唑和吩噁嗪前体，未观察到光环化反应，这通过密度泛函理论（DFT）计算方法得到了合理的解释。通过光谱（紫外可见光谱、电子顺磁共振）和电化学方法对这两个咔唑衍生的自由基进行了表征，同时对其中一个进行了结构（X射线衍射）和磁性（超导量子干涉仪）分析。后者的分析揭示了固态中的铁磁相互作用，居里温度(T_c = 16.6 K)。用DFT方法分析了这类新型稳定自由基的首个实例的性质，证实了氮原子对电子性质有显著影响以及额外15%的自旋离域。
