Chiral dinuclear Ln(iii) complexes derived from S- and R-2-(6-methoxy-2-naphthyl)propionate. Optical and magnetic properties

Abstract

The reaction of LnCl₃·6H₂O with (S)-(+)-2-(6-methoxy-2-naphthyl)propionic acid (S-HL), best known as naproxen, and 1,10-phenanthroline (phen) in EtOH allows the isolation of dinuclear chiral compounds S-1–4 of the formula [Ln₂(S-L)₆(phen)₂]·3DMF·H₂O [Ln(III) = Eu (1), Gd (2), Tb (3) and Dy (4)]. The use of the R-enantiomeric species of the HL ligand led to complexes R-1–4 with the formula [Ln₂(R-L)₆(phen)₂]·3DMF·H₂O. Compounds R- andS-1, 3 and 4 show strong sensitized metal-centred luminescence in the visible region. Moreover, Dy(III) complexes R- andS-4 display field-induced single-molecule magnet (SMM) behaviour. For chiral and emissive compounds circularly polarized luminescence (CPL) measurements have also been performed.