Reversible transformation between chiral and achiral Dy₆Mo₄clusters through a symmetric operation

Abstract

Three polynuclear lanthanide clusters: (NH4)2[Dy6Mo4O12(rac-L(3-))4(OOCCH3)8]·4CH3OH·6H2O (I), (Et3NH)2[Dy6Mo4O12(rac-L(3-))4(OOCCH3)8]·18H2O (II), and (Me4N)2[Dy6Mo4O12(rac-L(3-))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.