4 years ago

Cation-Directed Isomerization of the U28 Uranyl-Peroxide Cluster

Cation-Directed Isomerization of the U28 Uranyl-Peroxide Cluster
Jie Qiu, Gwendolyn Bogard, Mateusz Dembowski, Christopher A. Colla, Anna F. Oliveri, Peter C. Burns, Joseph R. Callahan, William H. Casey
The conformational dynamics of nanometer-sized actinide ions are exceptionally sensitive to the choice of counter-cations. A new means of following these dynamics in solution is presented that follows 1H NMR signals. The direct bond between hydrogen and phosphorus atoms in the bridging phosphonic groups of the [(UO2)28(O2)20(PHO3)24(H2O)12]32– (U28) cluster allows unparalleled recording of the orientations of these bridges in situ. The µ3-PHO3 bridges are organized into two supersets of conformers (facing inward vs. outward from the cluster), but each of these supersets additionally have four subsets that can be identified based upon orientations of the lone pairs of electrons in the associated oxygen atoms. The ensemble of these subsets changes over days or weeks depending upon bulk solution chemistry, temperature, and pressure. They also reflect cations trapped within the molecule. The 1H NMR spectra at room temperature indicate that the molecular orientation of this enormous ion tunes itself in response to solution composition, which suggests a strategy for selecting host–guest combinations.The phosphonic bridges of a nanometer-sized anion, [(UO2)28(O2)20(PHO3)24(H2O)12]32– (U28), form an array of conformers that depend sensitively on the identity of counterions. The hydrogen atom of the µ3-PHO3 bridges can face inward or outward from the cluster. Four additional subsets can be distinguished by 1H NMR spectroscopy, which correspond to the directions of the lone pairs on the oxygen atoms.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/ejic.201701074

You might also like
Discover & Discuss Important Research

Keeping up-to-date with research can feel impossible, with papers being published faster than you'll ever be able to read them. That's where Researcher comes in: we're simplifying discovery and making important discussions happen. With over 19,000 sources, including peer-reviewed journals, preprints, blogs, universities, podcasts and Live events across 10 research areas, you'll never miss what's important to you. It's like social media, but better. Oh, and we should mention - it's free.

  • Download from Google Play
  • Download from App Store
  • Download from AppInChina

Researcher displays publicly available abstracts and doesn’t host any full article content. If the content is open access, we will direct clicks from the abstracts to the publisher website and display the PDF copy on our platform. Clicks to view the full text will be directed to the publisher website, where only users with subscriptions or access through their institution are able to view the full article.