Structural variability, topological analysis and photocatalytic properties of neoteric Cd(II) coordination polymers based on semirigid bis(thiazolylbenzimidazole) and different types of carboxylic acid Linkers

A series of novel Cd-II coordination complexes, formulated as {[Cd(btbb)(0.5)(p-phda)]center dot H2O}(n), (1), [Cd(btbb)(0.5)(oba)](n), (2), {[Cd-2(btbb)(m-bdc)(2)(H2O)]center dot 2H(2)O}(n) (3), {[Cd(btbb)(0.5)(btec)(0.5)(H2O)]center dot 2H(2)O}(n) (4), [Cd(btbb)(0.5)(o-bdc)](n) (5) and {[Cd-2(btbb)(bptc)(H2O)]center dot 4H(2)O}(n) (6) (btbb = 1,4-bis(2-(4-thiazolyl)benzimidazol-1-ylmethyl)benzene, H(2)phda = phenylenediacetic acid, H(2)oba = 4,4'-oxybis(benzoic acid), m-H(2)bdc = 1,3-benzenedicarboxylic acid, H(4)btec = 1,2,4,5-benzenetetracarboxylate, o-H(2)bdc = 1,2-benzenedicarboxylic acid, H(4)bptc = 3,3',4,4'-benzophenone tetracarboxylic acid), have been obtained by solvothermat/hydrothermal reactions for the exploration of efficient photocatalytic degradation of organic dye pollutants. Complex 1 features a 6-connected 3D pcu alpha-Po primitive cubic topology net with the point symbol 4(12)center dot 6(3). Interestingly, complexes 2, 3 and 5 contain left- and right-handed helical chains (2: a 2-fold interpenetrating 3D architecture with {4(12)center dot 6(3)}-pcu topology network: 3: a (3,6)-connected net with a vertex symbol (4(2)center dot 5(4)center dot 6(6)center dot 7 center dot 8(2))(4 center dot 6(2)); 5: a (3,4)-connected 3,4L83 topology net with point symbol (4(2)center dot 6)(4(2)center dot 6(3)center dot 8)). Complex 4 exhibits a (3,4)-connected 3,4T48 topology net with point symbol (8(4)center dot 10(2))(8 center dot 10(2)), while complex 6 possesses a (3,5)-connected 3,5L2 topology with the point symbol (4(2)center dot 6)(4(2)center dot 6(7)center dot 8). Furthermore, the photophysical studies indicate that the relatively narrow optical energy gaps of complexes 1-6 (<2.30 eV) calculated from the diffuse reflectivity spectra reflect their outstanding semiconductive nature. The photocatalytic properties of complexes 1-6 were studied in detail, and the results demonstrate their good photocatalytic activities in methylene blue (MB) degradation reactions, especially for complexes 3, 4 and 6 (3: 91.4%, 4: 92.7%, 6: 86.7%).