Three new 2-D metal-organic frameworks containing 1-D metal chains bridged by N-benzesulfonyl-glutamic acid: Syntheses, crystal structures and properties

To explore the possibility of obtaining the metal-organic frameworks (MOFs) bearing the bsgluH₂ ligand, two new Cd(II) and one Cu(II) coordination polymers, Cd(bsglu)(bipy)]_n (1), Cd(bsglu)·(H₂O)]_n (2) and {Cu₂(bsglu)₂(bipy)₂]·4H₂O}_n (3) (bsglu=N-benzesulfonyl-glutamic acid bianion, bipy=2,2′-bipyridine) were synthesized and characterized by IR, elemental analysis and X-ray diffraction analysis. Compounds 1 and 3 exhibit one-dimensional coordination chains, which are further connected to form two-dimensional supramolecular networks through π-π aromatic stacking interactions in a novel zipper-like way. Compound 2 presents a two-dimensional layer structure. To the best of our knowledge, 2 is the first two-dimensional complex formed from transition metal and bsgluH₂ ligand. Interestingly, the bsglu anion exhibits remarkable versatile coordination modes in these complexes. Fluorescent analyses show that 1 exhibits photoluminescence in the solid state. Magnetic measurements for 3 revealed that the Cu(II) chain exhibit a weak antiferromagnetic behavior with a J value of −0.606 cm⁻¹.