1356032-45-5Relevant articles and documents
A mixed-linker ZIF containing a photoswitchable phenylazo group
Bernt, Stephan,Feyand, Mark,Modrow, Antje,Wack, Julia,Senker, Juergen,Stock, Norbert
, p. 5378 - 5383 (2011)
We report the synthesis and characterization of the new switchable Zn-based zeolitic imidazolate framework (ZIF) [Zn(Im)(aIm)] (1). The high-throughput investigation of the mixed linker system Zn2+/imidazole (HIm)/2-phenylazoimidazole (HaIm)/DMF at 85 °C led to 1, which is isostructural to ZIF-8 and crystallizes in a sodalite (SOD)-type structure. The preparation was also studied with microwave-assisted heating and ultrasound-assisted synthesis. The crystal structure was determined from single-crystal X-ray diffraction data. Although Im- and aIm - ions are present in a 1:1 molar ratio, no ordering of the 2-phenylazo group was observed. Incorporation of the Im- and aIm - linkers as an integral part of the framework structure was confirmed by elemental analysis, 13C and 15N MAS NMR, IR and Raman spectroscopy. In addition, the permanent porosity of 1 was demonstrated by N2 sorption experiments and a specific surface area of SBET = 580 m2g-1 is observed. The photoswitching properties were investigated by UV/Vis spectroscopy as the cis and trans isomers exhibit different UV absorption spectra. Switching can be achieved by irradiation with UV light (λ = 355 nm), and back-switching using visible light (λ = 525 nm). Although changes in the UV/Vis spectra are detected, the switching process is only partially reversible.
