Synthesis, structures, and luminescent and magnetic properties of Ln-Ag heterometal-organic frameworks.

摘要: A series of Ln-Ag heterometal-organic frameworks based on 4-hydroxylpyridine-2,6-dicarboxylic acid (H(3)CAM) with formulas {LaAg(2)(CAM)(HCAM)(H(2)O)(2)}(n) (1), {LnAg(HCAM)(2)(H(2)O)(3)}(n) (Ln = Pr, 2; Nd, 3; Sm, 4; Eu, 5), and {LnAg(3)(CAM)(2)(H(2)O)}(n) Gd, 6; Tb, 7; Dy, 8; Tm, 9; Yb, 10), have been synthesized the hydrothermal reaction Ln(OH)(3), Ag(2)O, H(3)CAM at 160 degrees C. The single-crystal X-ray diffraction analyses reveal that three kinds structures are exclusively governed by size lanthanide ions progression is mainly ascribed to contraction effect. Compound 1 consists a 3D network an alpha-polonium-like Ag(+)-homometallic net helical La(3+) chain. Compounds 2-5 display 2D honeycomb-like structure 18-membered Ln(3)Ag(3)O(12) motifs, compounds 6-10 can be described as sandwich-like framework built Ln(3+)-4(4) layer. In 4 (Sm), 5 (Eu), 7 (Tb), 8 (Dy) samples, efficient energy transfer from CAM Ln(III) was observed, which results in typical intense emissions corresponding visible region, strongest (4)G(5/2) --> (6)H(7/2) (602 nm), (5)D(0) (7)F(2) (614 (5)D(4) (7)F(5) (548 (4)F(9/2) (6)H(13/2) (576 nm) transitions. Variable-temperature magnetic susceptibility measurements show ferromagnetic interaction between gadolinium(III) appears 6, whereas mu(eff) values 7-10 smoothly decrease cooling. For orbital contribution ions, it very difficult determine intrinsic interactions ions.