title: Reduction-Triggered Self-Assembly of Nanoscale Molybdenum Oxide Molecular Clusters.
abstract: Understanding the formation mechanism of giant molecular clusters is essential for rational design and synthesis of cluster-based nanomaterials with required morphologies and functionalities. Here, typical synthetic reactions of a 2.9 nm spherical molybdenum oxide cluster, {Mo132} (formula: [Mo(VI)72Mo(V)60O372(CH3COO)30(H2O)72](42-)), with systematically varied reaction parameters have been fully explored to determine the morphologies and concentration of products, reduction of metal centers, and chemical environments of the organic ligands. The growth of these clusters shows a typical sigmoid curve, suggesting a general multistep self-assembly mechanism for the formation of giant molecular clusters. The reaction starts with a lag phase period when partial Mo(VI) centers of molybdate precursors are reduced to form {Mo(V)2(acetate)} structures under the coordination effect of the acetate groups. Once the concentration of {Mo(V)2(acetate)} reaches a critical value, it triggers the co-assembly of Mo(V) and Mo(VI) species into the giant clusters.
authors.affiliation: Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.|Shull Wollan Center, Neutron Sciences Directorate, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
authors.forename: Panchao
authors.initials: P
authors.lastname: Yin
authors.affiliation: Department of Physics and Astronomy, University of Tennessee , Knoxville, Tennessee 37996, United States.|Shull Wollan Center, Neutron Sciences Directorate, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
authors.forename: Bin
authors.initials: B
authors.lastname: Wu
authors.affiliation: X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory , Argonne, Illinois 60439, United States.
authors.forename: Tao
authors.initials: T
authors.lastname: Li
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
authors.forename: Peter V
authors.initials: PV
authors.lastname: Bonnesen
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
authors.forename: Kunlun
authors.initials: K
authors.lastname: Hong
authors.affiliation: X-Ray Science Division, Advanced Photon Source, Argonne National Laboratory , Argonne, Illinois 60439, United States.
authors.forename: Soenke
authors.initials: S
authors.lastname: Seifert
authors.affiliation: Institute Max Von Laue Paul Langevin , F-38042 Grenoble 9, France.
authors.forename: Lionel
authors.initials: L
authors.lastname: Porcar
authors.affiliation: Biology and Soft Matter Division, Neutron Sciences Directorate, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
authors.forename: Changwoo
authors.initials: C
authors.lastname: Do
authors.affiliation: Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.|Center for Nanophase Materials Sciences, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
authors.forename: Jong Kahk
authors.initials: JK
authors.lastname: Keum