New Lanthanide Metalloligands and Their Use for the Assembly of Ln–Ag Bimetallic Coordination Frameworks: Stepwise Modular Synthesis, Structural Characterization, and Optical Properties

Abstract

Stepwise self-assembly processes using new lanthanide metalloligands (Ln–MLs) and silver salts have been successfully applied to isolate 4f–4d heterometallic coordination networks of four different structural types. In particular, the new lanthanide tetrakis–chelate complexes NEt4[Ln(L1)4] [HL1 = 1,3-bis(4′-cyanophenyl)-1,3-propanedione; Ln = Eu (1a), La (1b), Nd (1c), Tb (1d)] and NEt4[Ln(L2)4] (HL2 = 1,3-bis(4′-pyridyl)-1,3-propanedione; Ln = Eu (1e), Nd (1f)] have been synthesized, characterized, and reacted with different silver salts. The use of NEt4[Ln(L1)4] allowed then to isolate and characterize i) neutral one-dimensional ladder-like species of formula [Ln(L1)4Ag] [Ln = Eu (2a), La(2b), Nd(2c), Tb(2d)] and ii) their supramolecular isomers [Ln(L1)4Ag] [Ln = Eu (3a), La (3b), Nd (3c), Tb (3d)] showing a very unstable 2D network structure, iii) the cationic 2D species [Ln(L1)4Ag2]X [Ln = Eu, X = PF6−, CF3SO3−, ClO4− (4a–4c); Ln = Tb, Nd, La X = PF6− (4d–4f)], and, only for lanthanum, iv) a fourth 2D...