Three luminescent Cd(II) coordination polymers containing aromatic dicarboxylate and flexible bis(benzimidazole) ligands as highly sensitive and selective sensors for detection of Cr2O72– oxoanions in water.

Three luminescent Cd(II) coordination polymers, {[Cd(TCPA)(L)]·H 2 O} n (1), {[Cd(1,2-BDC)(L)]·H 2 O} n (2) and [Cd 2 (1,3-BDC) 2 (L)(H 2 O) 2 ] n (3), were hydrothermally synthesized. 1 features a sql structure, 2 depicts a 1D ladder-like chain and 3 retains a 3,4L83 network. 1 , 2 and 3 exhibit highly selectivity and sensitivity for detection of Cr 2 O 7 2– anions. • Three new ternary Cd(II) coordination polymers were synthesized and characterized. • 1 , 2 and 3 display highly selective and sensitive detection of Cr 2 O 7 2– anions. • The luminescence quenching mechanisms of Cr 2 O 7 2– anions were discussed. Three Cd(II) coordination polymers (CPs), {[Cd(TCPA)(L)]·H 2 O} n (1), {[Cd(1,2-BDC)(L)]·H 2 O} n (2) and [Cd 2 (1,3-BDC) 2 (L)(H 2 O) 2 ] n (3) (H 2 TCPA = 2,3,5,6-tetrachloroterephthalic acid, 1,2-H 2 BDC = 1,2-benzenedicarboxylic acid and 1,3-H 2 BDC = 1,3-benzenedicarboxylic acid, L = 1,3-bis(5,6-dimethylbenzimidazol-1-yl)propane) were hydrothermally synthesized and characterized. 1 features a 2D {44} structure, which constructs a 3D supramolecular structure through π - π stacking interactions. 2 shows a 1D ladder-like chain which is additional extended into a 3D supramolecular network via π-π stacking interactions. 3 retains a 2D (3,4)-connected 3,4L83 net which can be broadened into a 3D supramolecular framework by O H···O hydrogen bonds. Both 1 , 2 and 3 could serve as efficient probes for detecting of Cr 2 O 7 2– anions with high quenching efficiency (K sv) values (7820 M−1, 9460 M−1 and 20018 M−1 for 1 , 2 and 3 , separately) and low detection limit (0.42 μM, 0.37 μM and 0.15 μM for 1 , 2 and 3 , respectively). [ABSTRACT FROM AUTHOR]