Details

Autor(en) / Beteiligte

• Wang, Bo
• Côté, Adrien P.
• Furukawa, Hiroyasu
• O’Keeffe, Michael
• Yaghi, Omar M.

Titel

Colossal cages in zeolitic imidazolate frameworks as selective carbon dioxide reservoirs

Ist Teil von

• Nature (London), 2008-05, Vol.453 (7192), p.207-211

Ort / Verlag

London: Nature Publishing Group UK

Erscheinungsjahr

2008

Quelle

EBSCOhost Psychology and Behavioral Sciences Collection

Beschreibungen/Notizen

• Get cagey with the CO 2 Zeolitic imidazolate frameworks, or ZIFs, are porous crystalline materials in which organic imidazolate links connect to transition metals to form a tetrahedral framework. Many different ZIF structures can be created by simply adjusting the link–link interactions. Wang et al . used this tactic to produce two new materials with structures of a scale and complexity rarely seen before. The resulting cages contain up to 264 vertices within the pore network, and are constructed from as many as 7,524 atoms. The cages can selectively capture and store carbon dioxide with high efficiency and this, combined with stability and ease of fabrication, makes giant ZIFs promising candidates for technologies aimed at reducing carbon dioxide emissions. Zeolitic imidazolate frameworks (ZIFs) are porous crystalline materials where organic imidazolate links connect to transition metals to form a tetrahedral framework. Intriguingly, many different ZIF structures can be created by simply adjusting the link-link interactions. Links that result in two new materials with structures of a scale and complexity rarely seen before have now been designed: huge and complex cages within the pore network contain up to 264 vertices, and are constructed from as many as 7,524 atoms. Zeolitic imidazolate frameworks (ZIFs) are porous crystalline materials with tetrahedral networks that resemble those of zeolites: transition metals (Zn, Co) replace tetrahedrally coordinated atoms (for example, Si), and imidazolate links replace oxygen bridges 1 . A striking feature of these materials is that the structure adopted by a given ZIF is determined by link–link interactions, rather than by the structure directing agents used in zeolite synthesis 2 . As a result, systematic variations of linker substituents have yielded many different ZIFs that exhibit known or predicted zeolite topologies. The materials are chemically and thermally stable, yet have the long-sought-after design flexibility offered by functionalized organic links and a high density of transition metal ions 1 , 2 , 3 , 4 , 5 , 6 , 7 . Here we report the synthesis and characterization of two porous ZIFs—ZIF-95 and ZIF-100—with structures of a scale and complexity previously unknown in zeolites 8 , 9 , 10 . The materials have complex cages that contain up to 264 vertices, and are constructed from as many as 7,524 atoms. As expected from the adsorption selectivity recently documented for other members of this materials family 3 , both ZIFs selectively capture carbon dioxide from several different gas mixtures at room temperature, with ZIF-100 capable of storing 28 litres per litre of material at standard temperature and pressure. These characteristics, combined with their high thermal and chemical stability and ease of fabrication, make ZIFs promising candidate materials for strategies aimed at ameliorating increasing atmospheric carbon dioxide levels.