title: Modular molecules: site-selective metal substitution, photoreduction, and chirality in polyoxometalate hybrids.
abstract: The first members of a promising new family of hybrid amino acid-polyoxometalates have emerged from a search for modular functional molecules. Incorporation of glycine (Gly) or norleucine (Nle) ligands into an yttrium-tungstoarsenate structural backbone, followed by crystallization with p-methylbenzylammonium (p-MeBzNH3(+)) cations, affords (p-MeBzNH3)6K2(GlyH)[As(III)4(Y(III)W(VI)3)W(VI)44Y(III)4O159(Gly)8(H2O)14]⋅47 H2O (1) and enantiomorphs (p-MeBzNH3)15(NleH)3[As(III)4(Mo(V)2Mo(VI)2)W(VI)44Y(III)4O160(Nle)9(H2O)11][As(III)4(Mo(VI)2W(VI)2)W(VI)44Y(III)4O160(Nle)9(H2O)11] (generically designated 2: L-Nle, 2 a; D-Nle, 2 b). An intensive structural, spectroscopic, electrochemical, magnetochemical and theoretical investigation has allowed the elucidation of site-selective metal substitution and photoreduction of the tetranuclear core of the hybrid polyanions. In the solid state, markedly different crystal packing is evident for the compounds, which indicates the role of noncovalent interactions involving the amino acid ligands. In solution, mass spectrometric and small-angle X-ray scattering studies confirm maintenance of the structure of the polyanions of 2, while circular dichroism demonstrates that the chirality is also maintained. The combination of all of these features in a single modular family emphasizes the potential of such hybrid polyoxometalates to provide nanoscale molecular materials with tunable properties.
authors.affiliation: School of Chemistry, University of Melbourne, Parkville, 3010 (Australia).
authors.forename: Michele
authors.initials: M
authors.lastname: Vonci
authors.forename: Fateme
authors.initials: F
authors.lastname: Akhlaghi Bagherjeri
authors.forename: Peter D
authors.initials: PD
authors.lastname: Hall
authors.forename: Robert W
authors.initials: RW
authors.lastname: Gable
authors.forename: Athanasios
authors.initials: A
authors.lastname: Zavras
authors.forename: Richard A J
authors.initials: RA
authors.lastname: O'Hair
authors.forename: Yuping
authors.initials: Y
authors.lastname: Liu
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Field
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Taylor
authors.forename: Johan
authors.initials: J
authors.lastname: Du Plessis
authors.forename: Gary
authors.initials: G
authors.lastname: Bryant
authors.forename: Mark
authors.initials: M
authors.lastname: Riley
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Sorace
authors.forename: Pablo A
authors.initials: PA
authors.lastname: Aparicio
authors.forename: Xavier
authors.initials: X
authors.lastname: López
authors.forename: Josep M
authors.initials: JM
authors.lastname: Poblet
authors.forename: Chris
authors.initials: C
authors.lastname: Ritchie
authors.forename: Colette
authors.initials: C
authors.lastname: Boskovic
keywords: amino acids; chirality; electronic structure; photoreduction; polyoxometalates