Four ZnII/CdII coordination polymers based on 3,3′-(pyridine-3,5-diyl) dibenzoic acid: Syntheses, crystal structures and photoluminescence property

Four new coordination polymers namely, [Zn(pddb)(H2O)]n (1), [Zn(pddb)]n (2), {[Cd2(pddb)2]·H2O}n (3) and [Cd(pddb)(H2O)2]n (4), have been solvothermally obtained. Among which, complexes 1 and 3 were prepared in presence of 4-nitrobenzoic acid, and complexes 2 and 4 not, respectively. Complex 1 shows a binodal 3,3-connected wavelike layer structure with the point symbol of (63)2. However, 2 performs a binodal 3,6-connected 3D coordination framework with the point symbol of (4·62)·(42·68·85). 3 exhibits a more complicated 3D periodic structure built on an infinite rod-shape secondary blocking units (SBUs), while 4 shows a double-chain structure, extended into 3D supramolecular framework through strong hydrogen bonding interactions. Furthermore, the study about photoluminescence properties of these four complexes and H2pddb ligand reveals that these diverse structures have significant influence on the photoluminescence signals.

Graphical abstractFour new coordination polymers namely, [Zn(pddb)(H2O)]n (1), [Zn(pddb)]n (2), {[Cd2(pddb)2]·H2O}n (3) and [Cd(pddb)(H2O)2]n (4), have been solvothermally obtained. Among which, complexes 1 and 3 were prepared in presence of 4-nitrobenzoic acid, and complexes 2 and 4 not, respectively. Furthermore, the study about photoluminescence properties of these four complexes and H2pddb ligand reveals that these diverse structures have significant influence on the photoluminescence signals.Figure optionsDownload full-size imageDownload as PowerPoint slide