Opening ZIF-8: a catalytically active zeolitic imidazolate framework of sodalite topology with unsubstituted linkers

A zeolitic imidazolate framework material of SOD topology possessing primarily unsubstituted imidazolate (im) linkers has been synthesized via solvent-assisted linker exchange (SALE) of ZIF-8. The structure of the new material, SALEM-2, has been confirmed through (1)H NMR and powder and single-crystal X-ray diffraction. SALEM-2 is the first example of a porous Zn(im)(2) ZIF possessing a truly zeolitic topology that can be obtained in bulk quantities. Upon treatment with n-butyllithium, the open analogue exhibits Brønsted base catalysis that cannot be accomplished by the parent material ZIF-8. Additionally, it displays a different size cutoff for uptake and release of molecular guests than does ZIF-8.