Three Zinc(II) Coordination Polymers Based on Tetrakis(4-pyridyl)cyclobutane and Naphthalenedicarboxylate Linkers: Solvothermal Syntheses, Structures, and Photocatalytic Properties

Solvothermal reactions of Zn(NO 3 ) 2 with tetrakis(4-pyridyl)cyclobutane (tpcb) and 1,4-naphthalenedicarboxylic acid (1,4-H 2 ndc) and 2,3-naphthalenedicarboxylic acid (2,3-H 2 ndc) in different solvents led to the formation of three polydimensional coordination polymers {[Zn 2 (H 2 O)(1,4-ndc) 2 (tpcb)]} n ( 1 ), {[Zn(1,4-ndc)(tpcb) 0.5 ]} n ( 2 ), and {[Zn 2 (H 2 O)(2,3-ndc) 2 (tpcb)]} n ( 3 ). Compounds 1 – 3 were characterized by elemental analysis, IR, powder X-ray diffraction (PXRD), and single crystal X-ray diffraction. Compound 1 is a three-dimensional (3D) (3,3)-connected net with a (10·12 2 )·(10 2 ·12) Schläfli symbol. Compound 2 holds a 2-fold interpenetrating 3D framework with a (4 2 ·6 2 ·7 2 )·(4·6 2 ·7 3 ) Schläfli symbol, which shows hexagonal-prism-like one-dimensional channels. Compound 3 shows a two-dimensional (3,8)-connected network. The solid state luminescent, optical, and thermal stability properties of 1 – 3 at ambient temperature were also investigated. A comparative study on their photocatalytic activity toward the degradation of methyl orange and methyl blue in polluted water was explored. The results provided some interesting insights into solvent effects on the structures of zinc(II) coordination polymers and their photocatalytic applications.