A series of lanthanide-organic polymers incorporating ethyl-4,5-imidazole-dicarboxylato and formate coligand: structures, luminescent and magnetic properties

Four new lanthanide-organic coordination polymers incorporating both nitrogen heterocyclic dicarboxylate and formate coligands, namely, {[Ln(3)(Heimda)(4)(mu(2)-HCOO)center dot 4H(2)O]center dot 2H(2)O}(n), (Ln = Sm (1), Dy (2), Ho (3), Er (4), H(3)eimda = 1H-2-ethyl-4,5-imidazole-dicarboxylic acid) have been fabricated successfully and characterized systematically. The polymers 1-4 are isomorphous and isostructural, and are built from two dimensional (2-D) double decker networks based on the Ln(4)Heimda(4) tetranuclear basic carboxylate as a secondary building unit (SBU). The extensive hydrogen bonds stabilize the crystal structure, forming a 3-D supramolecular tectonics. The luminescence emission spectra of the polymers vary depending on which lanthanide(III) ion is present. Variable-temperature magnetic susceptibility measurements show that the same end-to-end bridging fashion of formate results in the different magnetic properties occurring between adjacent lanthanide(III) centers.