Large Tripodal Spacer Ligands for the Construction of Microporous Metal-Organic Frameworks with Diverse Structures and Photocatalytic Activities.

Two microporous complexes, [Zn(TATAB)(OCH3 )]⋅2 H3 O+ (1; TATAB=4,4',4''-[(1,3,5-triazine-2,4,6-triyl)tris(azanediyl)]tribenzoic acid), [Cu1.5 (µ2 -O)TATAB*] (2; TATAB*=4,4'-{[6-(dimethylamino)-1,3,5-triazine-2,4-diyl]bis(azanediyl)}dibenzoic acid) have been synthesized and characterized by elemental analysis, IR spectroscopy, UV absorption spectroscopy, and thermogravimetric analysis, and by powder XRD and single-crystal XRD analysis. Structural analyses revealed that complex 1 possesses a 3D porous framework with uncoordinated water molecules trapped in the pores; the dimensions of the channels are approximately 29.2×12.3 Å2 . Complex 2 has a 3D microporous network structure. In addition, the surface photovoltage and photocatalytic activities were also studied. The photocatalytic properties of the two complexes were investigated by the decomposition of methylene blue under UV and visible-light irradiation. The results revealed that 2 possessea a higher photocatalytic activity than 1 under UV or visible-light irradiation. The potential semiconductor and dye degradation properties of complexes 1 and 2 may be widely applied in the fields of chemical semiconductors and environmental protection in the future.

d7 /d8 Metal Complexes Constructed from 2,6-Bis(2-benzimidazolyl)pyridyl or 2,6-Di-(pyrazol-3-yl)pyridine Derivatives: Synthesis, Structure, Characterization, and Photocatalytic Activity.

By introducing 2,6-bis(2-benzimidazolyl)pyridyl and 2,6-di-(pyrazol-3-yl)pyridine derivatives as ligand in the reaction system, three new transition-metal coordination complexes have been successfully synthesized, namely, [Co(HL1 )2 ] (1), [Ni(HL1 )2 ] (2), and [Ni3 (H2 L2 )2 ⋅(HL2 )2 ]⋅(OH)3 ⋅(Ac)⋅H2 O (3) (H2 L1 =2,6-bis(benzimidazol-2-yl)pyridine and H2 L2 =2,6-di-(5-phenyl-1H-pyrazol-3-yl)pyridine). They are all characterized by elemental analysis, IR spectroscopy, UV absorption spectroscopy, thermogravimetric analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. Structural analysis shows that the structures of complexes 1 and 2 are similar. They are constructed from one metal (Co, Ni) atom and two 2,6-bis(benzimidazol-2-yl)pyridine ligands (HL1 - ); the HL1 - ligand is in the tridentate coordination mode with N3 donors. Complex 3 is a trinuclear Ni complex with four 2,6-di-(5-phenyl-1H-pyrazol-3-yl)pyridine (H2 L2 ) ligands, in which the H2 L2 possesses two coordination fashions: terminal tridentate and bridging tetradentate. In addition, the surface photovoltage spectroscopy and photocatalytic activities of complexes 1-3 were investigated in detail. The results reveal that complex 3 possesses higher photocatalytic activity.