Porous purple glass - a cobalt imidazolate glass with accessible porosity from a meltable cobalt imidazolate framework

摘要

We report the first microporous cobalt imidazolate glass obtained from a meltable cobalt-based zeolitic imidazolate framework, ZIF-62(Co). Crystalline ZIF-62(Co) is constructed from Co2+ cations and two different imidazolate-type linkers, namely conventional imidazolate and benzimidazolate. The microporous framework melts at similar to 430 degrees C and converts into a glass upon cooling to room temperature. X-Ray total scattering and Raman spectroscopy reveal that the local structure of the glass and the crystalline parent material are very similar. Magnetic measurements and X-ray diffraction uncover that ZIF-62(Co) partially decomposes upon melting and glass formation resulting in the reduction of similar to 3% of the Co2+ ions to metallic cobalt. Most importantly, the ZIF glass retains almost 50% of the porosity of crystalline ZIF-62(Co). Our results pave the way for the realisation of metal-organic framework glasses containing open shell metal ions, as well as the application of these porous glasses in gas separation, energy storage and catalysis.