Spacers-induced structural diversity of cobalt coordination polymers based on “V”-type dipyridylamide and dicarboxylic ligands: Fluorescent, magnetic and photocatalytic properties

Abstract

To investigate the effect of the spacers of “V”-type dipyridylamide and dicarboxylic ligands on the structural diversity of CoII coordination polymers, [Co(L1)(5-CH3-1,3-bdc)]·2H2O (1) [Co(L2)(5-CH3-1,3-bdc)(H2O)]·H2O (2) [Co(L2)(5-NO2-1,3-bdc)(H2O)]·H2O (3) [Co(L2)(1,3-bdc)(H2O)]·H2O (4) [Co(L2)(4,4′-oba)]·3H2O (5) and L2·2H2O (6) [L1=N,N′-bis(pyridine-3-yl)pyridine-2,6-dicarboxamide, L2=N,N′-bis(pyridine-3-yl)-5-methylisophthalic dicarboxamide, 5-CH3-1,3-H2bdc=5-methylisophthalic acid, 5-NO2-1,3-H2bdc=5-nitroisophthalic acid, 1,3-H2bdc=1,3-benzenedicarboxylic acid, 4,4′-H2oba=4,4′-oxybis(benzoic acid)] have been hydrothermally synthesized. Complexes 1–5 were characterized by IR spectroscopy, thermal analysis, TG and X-ray single-crystal diffraction. Complex 1 is a 2D structure based on (4,4)-connected [Co(5-CH3-1,3-bdc)] network and [Co(L1)] helixes. Complexes 2–4 feature isostructural 2D networks derived from Co-dicarboxylate linear chains and [Co(L2)] helixes. Complex 5 show 1D tubular structure constructed by two parrelled [Co(4,4′-oba)] linear chains and [Co(L2)] loops. Compound 6 is a 3D supramolecular structure extended by L2 ligands and water molecules. The effect of the spacers of “V”-type dipyridylamide and dicarboxylic ligands on the structures of the title compounds were discussed. The magnetic property of 1, the fluorescent behaviors of 1–6 and photocatalytic properties of 1–5 under UV irradiation were studied.