Syntheses And Properties Of Lanthanide 3-methyl/tert-butyl-adipate Coordination Polymers

In this paper,two series of lanthanide-organic coordination polymers?CPs?[Ln₂?L¹?₃?H₂O?₄][Ln=Nd?1?,Sm?2?,Eu?3?,Gd?4?,Tb?5?,Dy?6?,H₂L¹=3-methyl-adipic acid]and[Ln₄?L²?₆?H₂O?₄][Ln=Nd?7?,Sm?8?,Eu?9?,Gd?10?,Tb?11?,Dy?12?,H₂L²=3-tert-butyl-adipic acid]have been synthesized by the solvothermal reactions of lanthanide salts with two flexible substituent adipates.These CPs were characterized by single-crystal X-ray diffraction,powder X-ray diffraction,elemental analysis,IR spectroscopy,and thermal analysis.Structural analyses reveal that CPs 1–6 and 7–12 are isostructural,respectively.In 1–6,the carboxyl groups of 3-methyl-adipates bridge two Ln1ions and two Ln2 ions to generate two types of Ln₂ units,respectively.These two types of Ln₂ units are linked by 3-methyl-adipates into two types of one-dimensional?1D?chains,respectively.These two types of 1D chains are alternately connected by 3-methyl-adipates to generate a two-dimensional?2D?layer.The neighboring 2D layers are further linked into a three-dimensional supramolecular framework via the hydrogen-bonding interactions.In 7–12,the 3-tert-butyl-adipate anions link four types of Ln ^IIIII ions to form a 1D strip-shaped chain.The adjacent 1D chains are further connected by the3-tert-butyl-adipate anions to construct a 2D layer.The substituent groups have an important effect on the formation of adipate-based lanthanide CPs.CPs 1–12 possess good thermal stability.CPs 2,3,5,6,9,11,and 12exhibit the characteristic emissions of rare earth ions,respectively.The Gd-containing CP 4 displays a weak ferromagnetic coupling between two Gd^IIIII ions below 10 K.The Dy-containing CPs 6 and 12 show weak slow magnetic relaxation behaviors under zero direct current field.