Magneto-optical Properties of Chiral Co₂Ln and Co₃Ln₂ (Ln = Dy and Er) Clusters

Abstract

A series of chiral heterometallic Ln−Co clusters, denoted as Co 2 Ln and Co 3 Ln 2 (Ln = Dy and Er), were synthesized by reacting the chiral chelating ligand (R/S)-2-(1-hydroxyethyl)pyridine (Hmpm), CoAc 2 •4H 2 O, and Ln(NO 3 ) 3 •6H 2 O. Co 2 Ln and Co 3 Ln 2 exhibit perfect mirror images in circular dichroism within the 320−700 nm range. Notably, the Co 2 Er and Co 3 Er 2 clusters display pronounced magnetic circular dichroism (MCD) responses of the hypersensitive f−f transitions 4 I 15/2 − 4 G 11/2 at 375 nm and 4