Reaction of Silyl radicals within a Porphyrin π-Cloud

合成了一系列轴向含烷基(sp^3)、烯基(sp^2)、芳基(sp^2)和炔基(Sp)的有机硅卟啉。在可见光照射下，二烷基硅卟啉与氮氧基化合物反应，如TEMPO，生成二硝氧基硅卟啉。在没有含氮化合物的情况下，光解生成了一种长寿命(-gt；25℃，50天)活性硅双自由基，其g值为2.0026，在黑暗中不与含氮化合物反应，但在可见光激发下被TEMPO顺利捕获，生成二硝氧基硅络合物。在自由氮氧化合物存在的情况下，用可见光照射二硝氧基硅，导致可逆轴向配体交换，该交换响应于光的开启和关闭而进行，以达到平衡。

A series of organosilicon porphyrins) with alkyl (sp^3), alkenyl, aryl (sp^2), and alkynyl (sp), groups at the axial positions were synthesized. Upon irradiation with visible light, dialkylsilicon porphyrins reacted with nitroxy compounds, such as TEMPO to give dinitroxysilicon porphyrins. In the absence of nitroxy compounds, photolysis resulted in the formation of a long-lived (>50 days at 25℃) EPR-active silicon diradical with a g-value of 2.0026, which did not react with nitroxy compounds in the dark but was smoothly trapped by TEMPO to give dinitroxysilicon complex upon excitation with visible light. Irradiation of the dinitroxysilicon with visible light in the presence of free nitroxy compoundss resulted in reversible axial ligand exchange, which proceeded in response to the switching-on and-off of the light, to reach an equilibrium.