文摘
A novel carbazolyl calixarene (calix[3]dimethoxycarbazole, 2) has been successfully synthesized. This macrocycle exhibits highly selective colorimetric signal towards Cu2+ over the other tested metal ions, due to the formation of the carbocationic intermediate. The above “on” colorimetric signal could be “turned off” via disassociating the 2-Cu2+ complexation and, the signal is “turned on” again once the 2-Cu2+ complexation recovers. The above “on-off-on” switch could be reversibly managed up to 6 cycles, so that 2 could serve as a switching Cu2+ sensor.