Affiliations 

  • 1 College of Chemistry and Chemical Engineering and Henan Key Laboratory of Function Oriented Porous Materials, Luoyang Normal University, Luoyang 471934, China. fengx@lynu.edu.cn
  • 2 College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou,450001, China
  • 3 The University of Nottingham Malaysia Campus, 43500, Semenyih, Selangor, Malaysia
  • 4 School of Life Science and Technology, Nanyang Normal University, Nanyang, 473601, China. wlya@lynu.edu.cn
Dalton Trans, 2017 Oct 24;46(41):14192-14200.
PMID: 28990615 DOI: 10.1039/c7dt02974h

Abstract

A series of coordination polymers {[Ln(aobtc)(H2O)4]·Hbipy·H2O}n (H4aobtc = azoxybenzene-2,2',3,3'-tetracarboxylic acid, bipy = 4,4'-bipyridine, and Ln = Sm(1), Eu(2), Gd(3), Tb(4), Dy(5), Er(6)) have been synthesized and characterized systematically. The cationic Hbipy(+) guest incorporated polymers are isostructural sets, featuring a one-dimensional (1D) zigzag double chain edifice composed of binuclear clusters [Ln2(H4aobtc)2], with the Hbipy(+) guest being located on two sides. These 1D chains are further interlinked into a 2D layer structure, and further extended into a 3D framework through hydrogen bonding interactions. The luminescence emission spectra of polymers 2 and 3 are based on the H4aobtc acid ligands, while 1 and 4 display the characteristic f-f transitions of Ln(iii) ions. Magnetic measurements revealed the presence of ferromagnetic behavior in polymer 3. The magnetic behaviors of 4 and 6 are ascribed to the depopulation of the Stark levels and/or weak antiferromagnetic interactions within MOFs at lower temperature. Slow relaxation is observed through the alternating-current susceptibility measurements for 5 at lower temperature, and the coexistence of weak ferromagnetism corresponding to the spin-canting-like behavior.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.