Introducing a photo-switchable azo-functionality inside Cr-MIL-101-NH2 by covalent post-synthetic modification.
For the first time an azo functionality was covalently introduced into a MOF by post-synthetic modification. The reaction of Cr-MIL-101-NH(2) with p-phenylazobenzoylchloride (1) and 4-(phenylazo)phenylisocyanate (2) as the reactants led to the compounds Cr-MIL-101_amide and Cr-MIL-101_urea, with the azo groups protruding into the mesoporous cages. XRPD and N(2) sorption measurements confirm the intactness of the framework and the successful covalent modification was proven by IR- and NMR-spectroscopy. Furthermore, cis/trans isomerisation upon irradiation with light was demonstrated by UV/Vis spectroscopy. More distinct changes in the UV/Vis spectra were observed for Cr-MIL-101_amide compared to Cr-MIL-101_urea, while the degree of functionalization, i.e. the number of reacted NH(2)-groups, seems to have a less pronounced effect. The variation of the sorption properties due to the cis/trans isomerisation was proven by methane adsorption measurements.
Institut für Anorganische Chemie, Christian-Albrechts-Universität, Max-Eyth-Strasse 2, D-24118 Kiel, Germany.
Antje
A
Modrow
Dordaneh
D
Zargarani
Rainer
R
Herges
Norbert
N
Stock
D000327:Adsorption; D000577:Amides / Q000737:chemistry; D001565:Benzoates / Q000737:chemistry; D017608:Chromium Compounds / Q000737:chemistry*; D017953:Isocyanates / Q000737:chemistry; D008697:Methane / Q000737:chemistry; D009942:Organometallic Compounds / Q000737:chemistry*; D014466:Ultraviolet Rays; D014508:Urea / Q000737:chemistry
D000577:Amides; D001565:Benzoates; D017608:Chromium Compounds; D017953:Isocyanates; D009942:Organometallic Compounds; C015432:4-phenylazobenzoyl chloride; D014508:Urea; D008697:Methane