title: Enantioselective resolutions and circular dichroism studies of lanthanide-containing Keggin-type [Ln(PW11O39)2](11-) polyoxometalates.
abstract: Enantiopure crystals of K(1.3)Na(3.2)H(6.5)[l-Pr(PW(11)O(39))(2)]·8.3l-proline·21.5H(2)O (1), K(1.3)Na(3.2)H(6.5)[d-Pr(PW(11)O(39))(2)]·8.3d-proline·17H(2)O (2), and K(1.3)Na(3.2)H(6.5)[l-Er(PW(11)O(39))(2)]·8.3l-proline·22.5H(2)O (3) were successfully obtained by using l- and d-proline (pro) as chiral auxiliary agents. In these crystals, l- and d-[Ln(PW(11)O(39))(2)](11-) anions are attached by two l- and d-pro molecules, respectively, through a O···N hydrogen-bonding interaction between the square-antiprismatic LnO(8) center and amino-N atoms. The l- and d-[Pr(PW(11)O(39))(2)](11-) anions in aqueous solutions exhibited a couple of mirror-imaged CD spectra due to (3)H(4/2)→(3)P(0,1,2) and (1)D(2) transitions in the stereogenic Pr(3+) center. Chirality inductions by l- and d-pro from a racemic solution of [Er(PW(11)O(39))(2)](11-) was demonstrated by means of CD spectroscopy.
authors.affiliation: Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama 226-8503, Japan. hnaruke@res.titech.ac.jp
authors.forename: Haruo
authors.initials: H
authors.lastname: Naruke
authors.forename: Jun
authors.initials: J
authors.lastname: Iijima
authors.forename: Takanobu
authors.initials: T
authors.lastname: Sanji
mesh_terms: D002942:Circular Dichroism; D056831:Coordination Complexes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D028581:Lanthanoid Series Elements / Q000737:chemistry*; D008958:Models, Molecular; D013237:Stereoisomerism; D017973:Tungsten Compounds / Q000737:chemistry*; D000099294:Polyoxometalates
chemical_list: D056831:Coordination Complexes; D028581:Lanthanoid Series Elements; D017973:Tungsten Compounds; C102296:polyoxometalate I; D000099294:Polyoxometalates