Synthesis of a series of coordination polymers based on mixed ligands to tune the structural dimension

Eight coordination polymers, namely, Mn(cob)(phen) (1), Co(cob)(phen) 2(H2O) center dot 5H(2)O (2), Co(cob)(phen) (3), Cd(cob)(phen) (4), Mn(cob)(bpy)(H2O)(2) (5), Co(cob)(bpy)(H2O)(2) (6), Cu(Hcob) 2(bpy)(H2O)(2) center dot H2O (7), Cd(cob)(bpy) (8) (H(2)cob = 2-[(4'- carboxybenzyl) oxy] benzoic acid, phen = 1,10- phenanthroline, bpy = 2,2'- bipyridine) have been synthesized under hydrothermal conditions by H(2)cob, different N-donor ligands and transition metal salts. These eight complexes have been characterized by elemental analysis, infrared (IR) spectroscopy, thermogravimetric analysis (TGA), and single-crystal X-ray diffraction. Complexes 1, 3 and 4 are isostructural and feature two-dimensional (2D) wave-like layer networks, which are further interconnected by inter-layer p. p stacking interactions to form three-dimensional (3D) supramolecular structures. Complexes 2 and 7 are both mononuclear structures which are further self-assembled through hydrogen bonding and p. p stacking interactions to generate 3D supramolecular structures. Complexes 5 and 6 are isostructural and show one-dimensional (1D) zigzag chains, which are further connected by hydrogen bonding to form a 2D supramolecular structure. Complex 8 is an infinite 1D linear structure. Desorption of lattice water molecules in complexes 2, 5 and 6 was analyzed, and demonstrates that these water molecules may influence the construction of the final structures. The water sorption studies reveal that complexes 2, 5 and 6 exhibit good water vapor uptake (64.12 ml g(-1) for 2, 40.26 ml g(-1) for 5 and 55.34 ml g(-1) for 6). Furthermore, the fluorescence properties of 1-8 have been investigated. Magnetic susceptibility measurements indicate that complexes 1-3 show weak antiferromagnetic behavior, while 5-6 exhibit ferromagnetic behavior.