Three Ca(II)-Dy(III) heterometallic coordination polymers with different topologies and different water clusters: Synthesis and properties

Three new heterometallic polymers [DyL4Ca2(H2O)2.5(C2H5OH)0.5].Him.H2O (1), [Dy2L6Ca3(H2O)12].6H2O (2) and [Dy0.67L2Ca(H2O)2].4H2O (3) (H2L = 4-chloropyridine-2,6-dicarboxylic acid, im = imidazole) were pre-pared under solvothermal conditions. The single crystal determination showed that polymers 1 and 3 are two-dimensional structures and polymer 2 is three-dimensional structure. It was found that different types of water clusters were present in these three polymers. They exhibit different topologies with the topological symbols {43}2{46.66.83}, {42.6.123}2{42.6}2 and {63}, where polymer 2 is a new topological type. A series of characterizations, such as XRD, IR, TGA, and solid-state fluorescence, were carried out on these three crystalline materials. They all show characteristic emission spectra of Dy(III) ions. Their quantum yields CYRILLIC CAPITAL LETTER EFtotal are 4.01% (1), 2.25% (2), 2.88% (3), respectively.