Two novel R- and S-malato-bridged coordination polymers by reacting lanthanide chloride and maleic anhydride, 1,10-phenanthroline at hydrothermal condition

Two less common lanthanide coordination polymers, [Ln2(fum)(malate)2(phen)2]n·n1.25H2O (Ln=Eu, 1; Pr, 2. fum=fumarate, phen=1,10-phenanthroline) were synthesized and characterized by IR spectra and X-ray crystallography. Single crystal X-ray diffraction analysis shows that complex 1 is isostructural with complex 2. In the two complexes, we found a pair of enantiomers (R-malate and S-malate) which are obtained by addition reaction between maleate and water and fumarate which result from configurational tranformation of maleate. The two structures consist of coordination polymer chains along the c-axis which are held together solely through hydrogen bonding and π–π stacking. Three-dimension supramolecular structures are formed through the two types of weak interaction. The IR data are also described and compared with those of other similar complexes.