Lanthanoid Heteroleptic Complexes with Cucurbit[5]uril and Dicarboxylate Ligands: From Discrete Structures to One-Dimensional and Two-Dimensional Polymers.

Lanthanoid heteroleptic complexes with cucurbit[5]uril {Q[5]} and two dicarboxylate ligands, e.g., diglycolic acid (H2 DGC) and glutaric acid (H2 GT), have been investigated with six new compounds featuring a tetrametallic and dimetallic discrete structures, a one-dimensional (1D) polymer, and three two-dimensional (2D) polymers with a unique honeycomb-type topology being synthesized and structurally characterized. [La4 (Q[5])3 (DGC)2 (NO3 )2 (H2 O)12 ][La(DGC)(H2 O)6 ]·7NO3 · nH2 O (1) has a tetrametallic structure constructed with three bis-bidentate Q[5] ligands linking two [La(DGC)(H2 O)2 ]+ species in the middle and two [La(H2 O)4 (NO3 )]2+ species at both ends. [Ce2 (Q[5])(DGC)(NO3 )(H2 O)10 ]·3NO3 ·4H2 O (2) has a dimetallic structure built up with a bis-bidentate Q[5] ligand linking [Ce(DGC)(H2 O)3 (NO3 )] and [Ce(H2 O)7 ]3+ on each side of the Q[5] portals. [Ce3 (Q[5])3 (DGC)2 (H2 O)9 ][Ce(DGC)(H2 O)6 ]2 ·7NO3 · nH2 O (3) has a 1D polymeric structure built up with bis-bidentate Q[5] ligands in-turn linking one [Ce(H2 O)6 ]3+ and two [Ce(DGC)(H2 O)6 ]1+ cationic species. [Ln2 (Q[5])2 (GT)(H2 O)6 ]·4NO3 · nH2 O [Ln = La (4), Ce (5) and Nd (6)] have similar 2D polymeric structures built up with two types of 9-fold coordinated Ln polyhedra linked by Q[5] via bis-bidentate carbonyl groups on both sides forming 1D chains which are further connected by bridging GT2- ligands to form 2D polymers with a unique honeycomb-type topology. Their vibrational modes and electronic structures have also been investigated.