title: Breaking symmetry: spontaneous resolution of a polyoxometalate.
abstract: A chiral polyoxometalate [Hf(PW11O39)2]10- (1) has been prepared and structurally characterized. It crystallizes in the chiral space group P2(1)2(1)2, as a conglomerate of two enantiomerically pure crystals in the absence of any chiral source. The absolute configuration of 1 was determined from the Flack parameter by X-ray crystallography. The structure of 1 comprises two lacunary [PW11O39]7- units, each functioning as a tetra-dentate ligand sandwiching an 8-coordinate HfIV centre in a distorted square antiprismatic geometry. Optically active crystals of both enantiomers were spectroscopically distinguishable by means of solid state circular dichroism spectroscopy. This hafnium-substituted polyoxometalate (POM), 1, shows that spontaneous chiral resolution, a rare phenomenon, can be operable in POM systems.
authors.affiliation: Department of Chemistry, Emory University, 1515 Dickey Drive, Atlanta, GA 30322, USA.
authors.forename: Yu
authors.initials: Y
authors.lastname: Hou
authors.forename: Xikui
authors.initials: X
authors.lastname: Fang
authors.forename: Craig L
authors.initials: CL
authors.lastname: Hill