Syntheses, structures and properties of a series of heterometallic-organic frameworks based on pyridinedicarboxylic acids

Six novel heterometallic-organic frameworks (HMOFs), namely [LaCu(2,5-pydc)(2)(H2O)(4)Cl (1), [LaNi(2.5-pydc)2(H2O)(4)]Cl center dot 4H(2)O (2), [LaCu2Cl3(4,4'-bpdc)(2)(H2O)(3)]center dot H2O (3), [CeCuCl2 (5,5'-bpdc)(HCO3)(H2O)) (4), and [MSr2Cl(3,5-pydc)(2)(NO3)(H2O)]center dot 3.5H(2)O [M = Ni (5), Co (6)] (2,5-pydc = pyridine-2,5-dicarboxylic acid, 4,4'bpdc = 2,2'-bipyridyl-4,4'-dicarboxylic acid, 5,5'-bpdc = 2,2'-bipyridyl-5,5'-dicarboxylic acid, 3,5-pydc = pyridine-3,5-dicarboxylic acid), have been solvothermally synthesized on the basis of the coordination between alkaline earth/rare earth/transition metal ions and pyridinedicarboxylic acids. These HMOFs were characterized by single crystal X-ray diffraction, powder X-ray diffraction, elemental analysis, and thermogravimetric analysis. All these HMOFs have three-dimensional frameworks except compound 3 featuring a two-dimensional neutral layer. Magnetic property of 4 and luminescent spectra of 1-4 were studied.