3D Enantiomorphic Mg-Based Metal-Organic Frameworks as Chemical Sensor of Nitrobenzene and Efficient Catalyst for CO Cycloaddition.

Two enantiomorphic Mg -based metal-organic frameworks, {MgL(H O) } (1-D and 1-L) (where H L=2,2'-bipyridyl-4,4'-dicarboxylic acid) have been synthesized by solvothermal reaction without any chiral auxiliary. The single-crystal X-ray measurement and the structural analysis indicate that both 1-D and 1-L possess 2-fold interpenetrated frameworks with different left- and right-handed helical chains simultaneously, which serve as chiral source, thus transmitting chirality over the whole frameworks. The fluorescence measurements reveal that they exhibit a strong quenching response to nitrobenzene and could be potentially used as a chemical sensor. Owing to the accessible Lewis acidic sites in channels, they display high catalytic efficiency for cycloaddition reaction of CO with epoxides and could be reused five times without losing activity.