Cd II ‐Organic Frameworks Fabricated with a N‐Rich Ligand and Flexible Dicarboxylates: Structural Diversity and Multi‐Responsive Luminescent Sensing for Toxic Anions and Ethylenediamine

Three metal‐organic frameworks {[Cd( L )(glu)]⋅3 H 2 O} ∞ ( 1 ), {[Cd 2 ( L ) 2 (adi) 2 ]⋅5 H 2 O} ∞ ( 2 ) and {[Cd( L )(sub)]⋅3 H 2 O⋅DMA } ∞ ( 3 ) ( L =pyridine‐3,5‐bis(5‐azabenzimidazole), H 2 glu=glutaric acid, H 2 adi=adipic acid and H 2 sub=suberic acid) were obtained under solvothermal conditions. Complex  1 shows a 2D (4,4) network constructing of Cd 2 ‐glu and Cd‐ L chains. Complex  2 presents a 2‐fold interpenetrating 3D framework with pcu topology. Complex  3 is a 3D framework with cds topology. Three complexes with versatile structures were obtained by changing aliphatic dicarboxylate ligands with different lengths based on a N ‐rich ligand. Moreover, the fluorescence measurements indicate that complex 1 is a good multifunctional chemosensor for the detection of Cr 2 O 7 2− and MnO 4 − anions by fluorescence quenching effect, and ethylenediamine by fluorescence enhancement effect, with detection limits of 1.196 ppm, 0.551 ppm and 64.572 ppm, respectively. Both complexes  2 and 3 can selectively sense Cr 2 O 7 2− anion with detection limits of 1.126 ppm for 2 and 0.831 ppm for 3 by a fluorescence quenching effect.