Supramolecular coordination polymers of La(III), Ce(III), Sm(III), Gd(III) and Eu(III) decorated with rigid 5-hydroxy-1,3-benzenedicarboxylate and flexible hexane-1,6-dicarboxylate linkers: Syntheses, structures, DFT study, luminescence and magnetic properties

摘要

Five new coordination polymers (CPs) with the formula [Ln (hip) (adiP)(0.5)(H2O)(2)](n)center dot nH(2)O [Ln = La (1), Ce (2), Sm (3) and Gd (4)] and [Ln(2)(hip)(2) (adip)(H2O)(4)](n)center dot 2nH(2)O [Ln = Eu (5)] were synthesized by self-assembly of lanthanide salts with rigid [5-hydroxyisophthalic acid (H(2)hip)] and flexible [adipic acid (H(2)adip)] linkers under solvothermal condition. The CPs 1-4 crystallizes in monoclinic C-2/c, space group, whereas CP 5 has triclinic P (1) over bar space groups respectively. The CPs 1-4 exhibit 1D linear ladder shaped extension with the linkage of lanthanide carboxylate chains having the backbone of H2hip and H2adip ligands, whereas CP 5 shows linear orthogonally twisted ladder shaped chains. The 1D linear ladder chains are grafted into three dimensional (3D) supramolecular frameworks via significant pi-pi and hydrogen bonding interactions. The DFT calculations support structures adopted by polymers. The CPs 3 (Sm) and 5 (Eu) emit strong ligand sensitized characteristic f-f luminescence emission. The CP 4 exhibit weak ferromagnetic interactions at low temperatures. (C) 2017 Elsevier Ltd. All rights reserved.