3 years ago

Crown Ether Complexes of Alkali-Metal Chlorides from SO2

Crown Ether Complexes of Alkali-Metal Chlorides from SO2
Stefan S. Rudel, Magnus R. Buchner, Kirsten Reuter, Florian Kraus, Carsten von Hänisch
The structures of alkali-metal chloride SO2 solvates (Li–Cs) in conjunction with 12-crown-4 or 1,2-disila-12-crown-4 show strong discrepancies, despite the structural similarity of the ligands. Both types of crown ethers form 1:1 complexes with LiCl to give [Li(1,2-disila-12-crown-4)(SO2Cl)] (1) and [Li(12-crown-4)Cl]⋅4 SO2 (2). However, 1,2-disila-12-crown-4 proved unable to coordinate cations too large for the cavity diameter, for example, by the formation of sandwich-type complexes. As a result, 12-crown-4 reacts exclusively with the heavier alkali-metal chlorides NaCl, KCl and RbCl. Compounds [Na(12-crown-4)2]Cl⋅4 SO2 (3) and [M(12-crown-4)2(SO2)]Cl⋅4 SO2 (4: M=K; 5: M=Rb) all showed S-coordination to the chloride ions through four SO2 molecules. Compounds 4 and 5 additionally exhibit the first crystallographically confirmed non-bridging O,O′-coordination mode of SO2. Unexpectedly, the disila-crown ether supports the dissolution of RbCl and CsCl in the solvent and gives the homoleptic SO2-solvated alkali-metal chlorides [MCl⋅3 SO2] (6: M=Rb; 7: M=Cs), which incorporate bridging μ-O,O′-coordinating moieties and the unprecedented side-on O,O′-coordination mode. All compounds were characterised by single-crystal X-ray diffraction. The crown ether complexes were additionally studied by using NMR spectroscopy, and the presence of SO2 at ambient temperature was revealed by IR spectroscopy of the neat compounds. Different class: The syntheses of the alkali-metal chloride SO2 solvates (Li–Cs; see figure) in conjunction with 12-crown-4 or 1,2-disila-12-crown-4 are described. The structures of the obtained complexes show large differences, despite the structural similarity of the ligands used.

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

DOI: 10.1002/chem.201701174

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.