Group I cation templated formation of luminescent mono- and bis-substituted thionaphthol heterobimetallic complexes of Pr, Nd, Eu and Tb

Abstract

Metathesis of lanthanide tris di-tert-butyl β-diketonates ([Ln(thd)₃] Ln = Pr, Nd, Eu, Tb) with one or two equivalents of group 1 salts of the sulfur bridged binaphtholate dianion [1,1′-S(2-OC₁₀H₄Bu^t₂-3,6)₂]²⁻, [M₂L], M = K, Li affords luminescent mono- and bis-ligand substituted complexes ML[LnL(thd)₂].L; M = K, Ln = Pr 1, Nd 2, Eu 3 and Tb 4 (L = thf, diethyl ether or toluene) and M(thf)₂[LnL₂(thd)]; M = Li, Ln = Pr 5, Nd 6, Eu 7, Tb 8. The potassium salt [K₂L] affords mono-L substituted complexes most cleanly, while the lithium salt [Li₂L] yields the bis-L substituted complexes most cleanly. The L ligands function as antenna for the sensitised lanthanide-centred emission in Eu³⁺ and Tb³⁺ complexes. The X-ray single-crystal structures of mono- and bis-L lanthanide complexes of Nd³⁺ are presented.