Syntheses, structures, photoluminescent and magnetic properties of pyrazine-2,3-dicarboxylate-based cadmium-lanthanide/lanthanide coordination polymers tuned by CdII.

Graphical abstract A series of 3D 2,3-pzdc-based lanthanide coordination polymers (2,3-pzdc = pyrazine-2,3-dicarboxylate) tuned by CdII have been successfully synthesized and structurally characterized. Their photoluminescent and magnetic properties as well as the magnetic properties of a 2,3-pzdc-based ZnII–DyIII heterometallic coordination polymer have been investigated. Highlights • Two types of 3D CPs have been prepared by the one-pot hydrothermal reactions. • The introduction of CdII has an important effect on the formation of 1 – 8. • CPs 4 (EuIII), 5 (TbIII), and 6 (DyIII) show intense photoluminescence. • CPs 6 (DyIII) and 9 (DyIII) exhibit field-induced slow magnetic relaxation behaviors. • This work provides a useful strategy for constructing the 2,3-pzdc-based CPs. Abstract The hydrothermal reactions of Ln(NO 3) 3 · n H 2 O, Cd(NO 3) 2 ·4H 2 O/Zn(NO 3) 2 ·4H 2 O, pyrazine-2,3-dicarboxylic acid (2,3-H 2 pzdc), and NaOH yielded a series of metal-organic coordination polymers (CPs) {[Ln 2 Cd(2,3-pzdc) 4 (H 2 O) 6 ]·2H 2 O} n [Ln = La (1), Pr (2), Nd (3)], {[Ln 2 (2,3-pzdc) 3 (H 2 O) 5 ]·3H 2 O} n [Ln = Eu (4), Tb (5), Dy (6), Ho (7), Er (8)], and {[Dy 2 Zn(2,3-pzdc) 4 (H 2 O) 6 ]·2H 2 O} n (9). They were characterized by single-crystal X-ray diffraction, elemental analysis, IR spectroscopy, powder X-ray diffraction, and thermogravimetric analysis. CPs 1 – 3 and 9 are isostructural and show a 3D framework formed by 2,3-pzdc linking CdII/ZnII and LnIII with a 3,3,4,4-connected {4.62} 2 {42.62.82}{63} 2 {65.8} 2 topology. CPs 4 – 8 are isostructural and exhibit a 3D framework constructed from the 2,3-pzdc anions bridging the LnIII ions with a 3,4-connected {4.6.8}{4.62.83} topology. Introduction of the CdII ion plays an important role in the formation of 1 – 8. CPs 4 – 6 display the characteristic fluorescent emissions of EuIII, TbIII, and DyIII, respectively. CPs 6 and 9 indicate field-induced slow magnetic relaxation behaviors. A ferromagnetic coupling between the intrachain DyIII ions was observed in 9. [ABSTRACT FROM AUTHOR]