Syntheses, Structures and Topology Variations of Metal Organic Frameworks Built From a Semi‐Rigid Tetracarboxylate Ligand

Abstract

AbstractA flexible ether bridged tetracarboxylic ligand, 5‐((3,5‐dicarboxybenzyl)oxy)isophthalic acid (H4L) has been used to construct five metal organic frameworks under solvothermal condition. Complex 4 and 5 have been synthesized in presence of pyridine based coligands, 6′‐(pyridin‐4‐yl)‐4,2′:4′,4′′‐terpyridine (L1). The products formed under these conditions are formulated as {[(Ni)1.5(L)(C5H5N)(H2O)](3H2O)}n (1), {[(Co)1.5(L)](C5H6N)(1.5H2O)}n (2), {[(Ni)(L)0.5(H2O)2.5](3H2O)}n (3), {[(Co)2(L)(L1)(DMF)(H2O)] (DMF)(4H2O)}n (4), {[(Cd)2(L)(L1)(DMF)(H2O)](DMF)(6H2O)}n (5). All of these complexes have been characterized by single‐crystal X‐ray diffraction, IR spectroscopy, thermogravimetry, elemental analysis, and powder X‐ray diffraction (PXRD) measurements. Compound 1 is one 2D layer structure, and compounds 2–5 are 3D coordination polymers (CPs)“. Interestingly, compound 4 and 5 are isostructural having 2D structure which lead to 3D by weak π⋅⋅⋅ π interaction between the two layers. Topological analysis of these complexes have been performed which reveals that 1 is (3,6)‐connected kgd net, 2 is (4,8)‐connected flu; sqc169 net, 3 is (4,4)‐connected dia diamond net while 4 and 5 have the same, (3,4)‐connected fsg net. Solid state photoluminescent studies were carried out of the complex 5 upon excitation at 290 nm and emission occurs at 453 nm which is attributed due to the ligand to metal charge transfer transition where as emission of the ligand L and L1 observed at 380 nm and 395 nm respectively.