2-Fold Interpenetrating Bifunctional Cd-Metal–Organic Frameworks: Highly Selective Adsorption for CO₂ and Sensitive Luminescent Sensing of Nitro Aromatic 2,4,6-Trinitrophenol

A robust primitive diamond-type topology 3-D metal–organic framework (MOF) of {[Cd 4 (hbhdpy) 2 (bdc) 3 (DMA) 2 ]·(H 2 O) 4 } n ( 1, DMA = N, N -dimethylacetamide) was constructed from the planar secondary building units of the dinuclear cadmium clusters, Cd 2 (μ 2 -O) 2, and two linear organic linkers of the new multidentate Schiff base of 4-(2-hydroxy-3-methoxy-benzyli-denehydrazino-carbonyl)- N -pyridin-4-yl-benzamide (Hhbhdpy) through the solvothermal reaction. 1 presents a 2-fold interpenetrating network along with confined narrow channels and rich acylamide groups as well as potential metal open sites for excellent selective CO 2 uptake over CH 4 /N 2 and high luminescent response for 2,4,6-trinitrophenol (TNP) in DMA solution under ambient conditions. With 2-amino-1,4-dicarboxy-benzene (H 2 bdc-NH 2 ) replacing H 2 bdc, an amine-functionalized MOF of {[Cd 4 (hbhdpy) 2 (bdc-NH 2 ) 3 (DMA) 2 ]·(H 2 O) 4 } n ( 1 -NH 2 ) as an isomorphism of 1, was synthesized under the same reaction conditions. Compared with 1, the corresponding bifunctional features of 1 -NH 2 is more obvious. To the best of our knowledge, it is the first reported interpenetrating Cd-MOFs with highly sensitive luminescence response for TNP molecules combined with excellent selectivity for CO 2 /N 2 and CO 2 /CH 4 .