Transformation of a Luminescent Benzimidazole-Based Yb<sub>3</sub> Cluster into a One-Dimensional Coordination Polymer

Reaction of the benzimidazole-based ligand 2-(1H-benzoimidazol-2-yl)-4-bromo-6-methoxy-phenol (HL) with LnCl<sub>3</sub>·6H<sub>2</sub>O in a 4:3 mol ratio in refluxing EtOH gave the trinuclear complexes [Ln<sub>3</sub>L<sub>4</sub>Cl<sub>4</sub>(H<sub>2</sub>O)<sub>2</sub>]·Cl·H<sub>2</sub>O·EtOH (<b>1</b>) (Ln = Tb (a), Er (b), Yb (c)) in 40−59% yields. Under similar conditions, but with the subsequent addition of Zn(OAc)<sub>2</sub>·2H<sub>2</sub>O to the reaction mixture, complex {[Yb<sub>3</sub>L<sub>4</sub>(OAc)<sub>4</sub>]·Cl·EtOH}<i><sub>n</sub></i> (<b>2</b>) can be isolated in 48% yield. <b>2</b> has a one-dimensional coordination structure in the solid state. All complexes display intramolecular π−π stacking and hydrogen bonded interactions in the solid state as well as lanthanide ion based luminescence in both solution and the solid.