Lanthanide Complexes Based on 1,3-Dimethylimidazolium-4-Carboxylate: Syntheses and Structures

The reactions of the norzoanemonine zwitterion, 1,3-dimethylimidazolium-4-carboxylate (L), with praseodymium(III), samarium(III), and europium(III) chlorides afford crystals of two types: the isostructural binuclear complexes [Ln(2)(mu-C6H8N2O2)(4)(HOCH3)(4)(H2O)(4)]Cl-6 (Ln = Pr(III) (I) and Eu(III) (II)) and the dimeric samarium complex [Sm-2(mu-C6H8N2O2)(4)(C6H8N2O2)(2)(H2O)(5)(OCH3)]Cl-5 (III), which are characterized by X-ray diffraction analysis and IR spectroscopy. In complexes I-III (CIF files CCDC nos. 1912829 (I), 1912830 (II), 1912831 (III), the metal atoms are bound by four bridging L molecules without forming the metal-metal bond (the M center dot center dot center dot M distances are 4.595 angstrom in I, 4.4637 angstrom in II, and 4.584 angstrom in III).