Porous metal-organic glass
Two researchers of the Department of Inorganic Chemistry and Technology (D09) participated in the discovery of the first porous metal-organic glass. As we have recently reported, glassy materials, consisting of metal centers and organic ligands, are the fourth type of glass beside oxide, metallic and organic glasses. Such glasses can be prepared by melting (and quench cooling) of crystalline zeolitic imidazolate frameworks or ZIFs. Even though many crystalline ZIFs are porous, the glasses prepared through vitrification of these ZIFs were thus far dense. In this last study the authors have, for the first time, prepared a porous glass, which could absorb notable amounts of several different gases. The key element in the preparation of the porous glass was the selection of a convenient parent crystalline ZIF, which had to contain bulky, partly-branched imidazolate ligands. After melt quenching such bulky ligands could not densify into a non-porous glass. The first successful preparation of a porous glass started from the crystalline ZIF-76 with imidazolate and chloro- or methyl-benzimidazolate ligands, and with large-pore LTA topology. The obtained porous metal-organic glass is actually the first case of a glass that is porous immediately upon vitrification. A small number of porous glasses, that we had known so far, were all obtained by post synthetic processing. Porous glasses could be used as membranes for chemical separation, as catalysts, sensors or in optics.
Andraž Krajnc and Gregor Mali from D09 collaborated in the study with the NMR analysis of the crystalline and glassy materials. The work was described in an article published in Nature Communications.
Full article can be found here: https://www.nature.com/articles/s41467-018-07532-z