Synthesis and structure of new europium() and terbium() coordination polymers with trans-1,4-cyclohexanedicarboxylic acid

Two new metal-organic frameworks of composition [Eu-2(phen)(2)Cl-2(chdc)(2)] center dot 1.1DMF center dot center dot 0.7diox (1 center dot 1.1DMF center dot 0.7diox, phen is 1,10-phenanthroline, DMF is N,N-dimethyl-formamide, diox is dioxane) and [Tb-2(phen)(2)Cl-2(chdc)(2)] center dot 2diox center dot 2H(2)O (2 center dot 2diox center dot 2H(2)O) were synthesized using the conformationally flexible alicyclic ligand, trans-1,4-cyclohexane-dicarboxylic acid (H(2)chdc). The mononuclear complex [Tb(phen)(2)(DEF)(H2O)Cl-2]Cl (3, DEF is N,N-diethylformamide) was also prepared. The structures of the reaction products were determined by single-crystal X-ray diffraction. The compositions and nature of the compounds 1 center dot 0.6DMF center dot 2.5H(2)O and 2 center dot 0.5diox center dot 4H(2)O, which were obtained after the separation of single crystals from the mother liquor, were confirmed by IR spectroscopy, elemental analysis, and thermogravimetric analysis. Both these compounds are composed of the binuclear units {Ln(2)(phen)(2)Cl-2(O2CR)(4)} and are rare examples of the coordination of a halide anion to the Ln(III) ion in the metal-organic framework. The three-dimensional packing of the layers in the structures of 1 and 2 contains voids with a total volume of 35 and 32%, respectively.