A photochromic NDI-based framework for the facile hydrazine sensor

It is desirable but still challenging to fabricate stable MOF analytes with suitable functional sites for hydrazine sensing. A facile hydrazine sensor based on the new photochromic-active calcium-NDIs MOF ([Ca2(ipNDI)(DMF)2(HOAc)(EtOH)], FJU-212) was successfully synthesized, which is highly stable even in the strong alkaline aqueous solution. Structural characterization studies suggest FJU-212 crystallizes in an interesting 3D polymeric framework with a 4,4,8-linked {412.616}{44.62}{45.6} network topology. Evidently, FJU-212 exhibits an appreciable sensitivity to detect hydrazine in either hydrazine aqueous solution or hydrazine vapor with a lower probe limit of 7.5 × 10−5 M, accompanied by a quick color conversion from light orange to dark black. And the sensor behavior may be attributed to the weak guest–host interactions between ipNDI and N2H4 molecules.