Chiral Erbium(III) Complexes: Single-Molecule Magnet Behavior, Chirality, and Nuclearity Control.

The reactions of chiral ligand ()/()-1,1'-binaphthyl-2,2'-diyl phosphate (-HL/-HL) and ErCl·6HO afford two pairs of di- and tetranuclear enantiomers [Er(/-L)(EtOH)]Cl·6.5EtOH (-, -) and [Er(PO)(/-L)(EtOH)(HO)]Cl(OH)·15EtOH·11HO (-, -). The nuclearity of these complexes is controllable and depends on the reaction temperature with a template effect. Their chirality was evidenced by circular dichroism (CD) spectra. - exhibits two magnetic relaxation pathways under a zero field, with an apparent barrier of 40 K. Ab initio calculations revealed a ferromagnetic dipolar interaction between these two Er(III) ions, the equatorial nature of the ligand field, and the probable origin of the two relaxations.