A Systematic Research on the Synthesis, Structures, and Application in Photocatalysis of Cluster-Based Coordination Complexes

To
search for effective photocatalysts in the field of cluster-based
coordination complexes, we synthesized {[Cd2­(dcpp)­(beb)2 (H2O)]·H2O}n (1), [Cd2­(dcpp)­(bmb)­(H2O)2]n (2), {[Cd2­(dcpp)­(2,2′-bipy)­(H2O)2]·2H2O}n (3), and {[Cd2­(dcpp)­(4,4′-bipy)0.5­(H2O)3]·H2O}n (4) by utilizing a butterfly-shaped
multidentate carboxylic acid (4,5-di­(4′-carboxyl­phenyl)­phthalic
acid) (H4dcpp)) and N-donor ligands (1,4-bis­(2-ethyl­benz­imidazol-1-ylmethyl)
benzene (beb), 1,4-bis­(2-methyl­benz­imidazol-1-ylmethyl)
benzene (bmb), 2,2′-bipyridine (2,2′-bipy), 4,4′-bipyridine
(4,4′-bipy)). Complexes 1–4 are constructed based on different SBUs. Complexes 1 and 2 possess three-dimensional (3D) pillar-layered
frameworks based on noncluster-type SBUs and dinuclear Cd2 clusters units, respectively. Complex 3 is a 3D porous
structure building on Cd4 clusters SBUs. Complex 4 is constructed from rare infinite botryoid-like Cd cluster
chains and exhibits a 3D complicated framework. The research on optical
energy gaps of complexes 1–4 indicates
that these complexes are potential semiconductive materials. Moreover,
complexes 1–4 are applied to catalyze
the reaction of photocatalytic degradation of methylene orange (MO)
under high-pressure mercury lamp irradiation. Excitingly, they exhibit
good photocatalytic properties in the presence of H2O2, and the degradation rates for 1–4 increase from 43% (without photocatalyst) to 97, 78, 85,
and 67%, respectively, after 100 min of irradiation. The photoluminescent
properties of complexes 1–4 were
also studied.