ZIF-8 as a promising storage material was investigated at high pressures up to ~39 GPa by in situ FTIR spectroscopy for the first time. Structural modifications are found to be reversible in a low-pressure region but irreversible in a high-pressure region. Overall, the ZIF-8 framework exhibits an unusual chemical stability even under extreme compression.

Due to the large porosity and unique framework stability, ZIF-8, a representative zeolitic imidazolate based member of metal-organic framework (MOF) family exhibited excellent adsorption capacities for a wide range of gases, including greenhouse gases. Using in situ FTIR spectroscopy, ZIF-8 framework was investigated when loaded with CO2 in a diamond anvil cell at high pressures far beyond the conventional gas adsorption pressure. The IR profile of CO2 as well as the ZIF-8 shows direct evidence of the interactions between CO2 and ZIF-8, indicating enhanced storage of CO2 in the framework. In addition, the storage behavior was found to be strongly pressure dependent, and the interaction mechanism was explored. These findings demonstrated great potential in the greenhouse gases storage applications using MOF based materials.

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Herein a strategy is reported for capturing and sensing iodine by strong I ⋅⋅⋅I ⋅⋅⋅I interaction, confined in a metal-organic framework, [Tb(Cu I )(ina) (DMF)] (1) (ina=isonicotinate). As revealed by single-crystal X-ray crystallography, the uptaken I molecules directly contact the {Cu I } chains, virtually forming an electronically polarizable tetraiodide anion (I ) through strong I ⋅⋅⋅I ⋅⋅⋅I interaction. As such, a quasi-copper-iodide layer of {Cu I } with semiconducting characteristics results, leading to a significant enhancement (Δ =10 times) in electrical conductivity over the I -free 1. The effect observed is several orders of magnitude higher than those reported due to iodine⋅⋅⋅aromatic interactions (Δ =10 times) and by interactions between I and a redox-active metal centre (Δ =10 times). The drastic enhancement in electrical conductivity was used to switch on/off an LED bulb, suggesting the possibility of electrically sensing I .