Reversible transformation between chiral and achiral Dy6Mo4 clusters through a symmetric operation

Abstract

Three polynuclear lanthanide clusters: (NH₄)₂[Dy₆Mo₄O₁₂(rac-L³⁻)₄(OOCCH₃)₈]·4CH₃OH·6H₂O (I), (Et₃NH)₂[Dy₆Mo₄O₁₂(rac-L³⁻)₄(OOCCH₃)₈]·18H₂O (II), and (Me₄N)₂[Dy₆Mo₄O₁₂(rac-L³⁻)₄(OOCCH₃)₈]·CH₃OH·14H₂O (III) (H₃L = (E)-2-((2,3-dihydroxypropylimino)methyl)-phenol) were synthesized. Single-crystal analysis reveals that cluster I crystallized in the centrosymmetric space group (P4₂/n), while clusters II and II crystallized in the chiral space group (P3₁21 or P3₂21), and cluster I can be transformed into clusters II and III, when Et₃NH⁺ and Me₄N⁺, respectively, are used to replace NH₄⁺. Investigation on the solid-state vibrational circular dichroism (VCD) spectra shows that the clusters II and III are homochiral crystallization. Powder X-ray diffraction study demonstrates that the transformation between chiral and achiral clusters is reversible.