Chiral Dy(III) Fluorescent Single-Molecule Magnet Based on an Achiral Flexible Ligand.

A novel multi-channel barcode module was developed by using chiral co-crystals which contain field-induced SMM behavior and different emission bands. The chiral co-crystals [Zn(H₂L)Dy(DBM)₂]₄(ClO₄)₄⋅9CH₃OH⋅H₂O (1a) and [Zn(H₂L)Dy(DBM)₂]₄(ClO₄)₄⋅8CH₃OH⋅0.5H₂O (1b) (H₄L = 2,2′-[1,2-ethanediylbis[(hydroxyethylimino)methylene]]bis[6-methoxy-4-methyl-phenol], HDBM = dibenzoylmethane) were obtained through one-pot reaction of Zn^II and Dy^III with the achiral ligands H₄L and HDBM. X-ray single crystal diffraction and CD spectroscopy confirmed that they are enantiomers crystallized in P4₃ (1a) and P4₁ (1b), both consisting of two ∆-[Zn(H₂L)Dy(DBM)₂]⁺ cations, two Λ-[Zn(H₂L)Dy(DBM)₂]⁺ cations and four (ClO₄)⁻ anions. The presence of Dy^III ions endow them with the property of field-induced slow magnetic relaxation. The relatively low energy barrier of 35.0(9) K for complex 1 may be due to the poor axiality of the ligand field caused by the long Dy-O_phenoxy bond lengths and the small O_phenoxy-Dy-O_phenoxy bond angles. Moreover, when the organic ligands H₄L (λ_ex = 350 nm) and Dy^III (λ_ex = 420 nm) are excited, different emission spectra are observed. [ABSTRACT FROM AUTHOR]