Two new Co(II)-MOFs based on polymeric chain building units: Crystal structures, and magnetic properties.

Two new Co(II) metal-organic frameworks, namely [Co 2 (bpm)(H 2 O) 3 (L)] n ( 1 ) and {[Co(bpe)(H 2 O)(H 2 L)]·(bpe) 0.5 ·(H 2 O)} n ( 2 ), (H 4 L=1,1′:2′,1″-terphenyl-3,3″,4′,5′-tetracarboxylic acid, bpm=bis(4-pyridyl)amine, bpe=1,2-bis(4-pyridyl)ethene), have been obtained under hydrothermal conditions. Both complexes 1 and 2 have been characterized by elemental analysis, IR spectra, single-crystal X-ray diffraction, powder X-ray diffraction (PXRD), and thermogravimetric analysis (TGA). Complexes 1 and 2 consist of 1D Co(II) chains bridging by carboxylate groups in syn-anti fashion. 1 shows a novel 3D tri-nodal (4,6,10)-connected net with a (3.4 3 .5 2 ) 2 (3 2 .4 14 .5 12 .6 12 .7 4 .8)(3 2 .4 2 .5 5 .6 4 .7 2 ) topology. While 2 exhibits a 2D sql layer. Magnetic susceptibility measurements indicate that both 1 and 2 show weak antiferromagnetic interactions between the adjacent Co(II) ions in 300–8 K for 1 and 300–16 K for 2 , respectively, and then 2 also displays ferromagnetic coupling at lower temperatures. [ABSTRACT FROM AUTHOR]