Synthesis and Characterization of Cerium(III), Praseodymium(III), Gadolinium(III) and Erbium(III) Coordination Polymers with Zwitterionic Ligand

Abstract Four new 2D coordination polymers based on 4-carboxy-1-(4-carboxybenzyl)pyridinium bromide (H2cbpyBr), formulated as {[Ce(µ-cbpy)(µ4-cbpy)(H2O)2]Br⋅7H2O⋅CH3CN}n (1), {[Pr(µ-cbpy)(µ4-cbpy)(H2O)2]Br⋅2H2O⋅CH3CN}n (2), {[Gd(μ-cbpy)(μ-cbpy)(μ-CHOO)]⋅4H2O⋅C2H5OH}n (3) and {[Er(μ-cbpy)(μ-cbpy)(μ-CHOO)]⋅2H2O⋅C2H5OH}n (4) were synthesized under solvothermal conditions and their characterizations were carried out with single crystal X-ray diffraction, IR spectroscopy, elemental and thermal analyses. Single-crystal X-ray diffraction analyses revealed that compounds 1-4 displayed 2D structures with 44.62 point symbol and sql topology. The adjacent 2D layers were extended to 3D supramolecular framework through the O-H⋅⋅⋅π and π⋅⋅⋅π interactions between pyridine and phenyl rings. The cbpy ligand in compounds 1-4 adopted four different coordination modes.