Synthesis and Characterization of the Cerium(III) UV-Emitting 2D-Coordination Polymer ∞2[Ce2Cl6(4,4′-bipyridine)4]•py

The 2D-coordination polymer (2)[Ce2Cl6(bipy)(4)]py (bipy = 4, 4-bipyridine) shows a 5d-4f centered emission in the soft UV-B region. It was synthesized via the reaction of anhydrous CeCl3 and 4, 4-bipyridine in pyridine under solvothermal conditions. The two-dimensional sheet structure consisting of 4, 4-bipyridine coordinated Ce2Cl6 dimers closes the gap between the known lanthanum (3)[La2Cl6(bipy)(5)]4bipy framework and the 2D networks of the formula (2)[Ln(2)Cl(6)(bipy)(3)]2bipy from praseodymium on. They differ in the number of coordinating bipy linkers, which decreases along La > Ce > Pr, with the remarkable observation that lanthanum, cerium, and praseodymium exhibit different network constitutions. The structure of (2)[Ce2Cl6(bipy)(4)]py exhibits a cem topology constituted of double strands, which are diagonally linked by 4, 4-bipyridine forming trapezoid cavities in-between the strands. The cavities contain intercalated pyridine molecules.