Four new coordination polymers with a Y-shaped tricarboxylic acid ligand: Structural diversities, luminescence sensing and magnetic properties

A new aromatic tricarboxylic acid with pyridine core, 4,4'-(4-(3-carboxyphenyl) pyridine-2,6-diyl)dibenzoic acid (H(3)cpdba), was used as a Y-shaped building block for the hydrothermal syntheses of four coordination polymers (CPs), namely [M(H(2)cpdba)(2)] (M = Zn, 1; Co, 2), [Zn-4(cpdba)(2)(mu-OH)(2)(PY)(4)]center dot H2O (3), and [Co-3(cpdba)(2)(py)(6)] (4). 1-4 were fully characterized by IR, elemental analyses, TGA, PXRD, and single-crystal X-ray diffraction. Their dimensionality ranges from 2D networks (1 and 2) to 3D frameworks (3 and 4), showing the dimensional/structural diversity of 1-4 is influenced by the level of deprotonation of H(3)cpdba ligand adjusted via organic solvent types, and the type of metal nodes (Zn-II or Co-II). Interestingly, 1 and 3 can serve as multi-responsive sensing materials for detecting Fe3+, Cr2O72- and nitrobenzene (NB). Moreover, the mechanism of the selective luminescence quenching response for Cr2O72- can be mainly ascribed to the competitive adsorption of excitation wavelength energy between 1 or 3 and Cr2O72-, meanwhile, Fe3+ ions and NB molecules contact with Lewis-base sites and aromatic rings respectively of H(3)cpdba ligand in 1 or 3, leading to the luminescent quenching. Furthermore, the magnetic properties of two Co-based CPs (2 and 4) have been investigated. The present work provides a promising approach to design and construct CPs or MOFs by adjusting types of solvents and/or metal nodes. (C) 2020 Elsevier B.V. All rights reserved.