Double-Cube-Shaped Mixed Chalcogen/Pentele Clusters from GaCl sub(3) Melts

• Published in: European journal of inorganic chemistry 2014-07, Vol.2014 (19), p.3043-3052
• Main Authors: Eich, Andreas, Hoffbauer, Wilfried, Schnakenburg, Gregor, Bredow, Thomas, Daniels, Jorg, Beck, Johannes
• Format: Article
• Language: English
• Subjects: Anions; Antimony; Bonding; Clusters; Mathematical analysis; Melts; NMR spectroscopy; Spectroscopy
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.201402230

The reactions of elemental antimony, tellurium, selenium and sulfur as well as antimony telluride and antimony sulfide in melts composed of GaCl sub(3)/SbCl sub(3)/ACl (A = Cu super(+), Ag super(+), PPh sub(4) super(+)) yielded Ag(Sb sub(7)Te sub(8))[GaCl sub(4)] sub(6) (1), (Sb sub(7)Se sub(8))[GaCl sub(4)] sub(2)[Ga sub(2) Cl sub(7)] sub(3) (2), (Sb sub(7)Se sub(8)Cl sub(2 ))[GaCl sub(4)] sub(3) (3) and (Sb sub(7)S sub(8)Cl sub(2))[GaCl sub(4)] sub(3) (4). SbCl sub(3) plays the role of the oxidant, and GaCl sub(3) plays the role of the Lewis acidic chloride ion acceptor. All of the compounds form orange, air-sensitive crystals. The crystal structures consist of discrete, double-cube-shaped, mixed antimony-chalcogen cationic clusters (Sb sub(7)Te sub(8)) super( 5+), (Sb sub(7)Se sub(8)) super( 5+), (Sb sub(7)Se sub(8)Cl sub(2 )) super(3+) and (Sb sub(7)S sub(8)Cl sub(2)) super(3+). The anions are discrete chloridogallate [GaCl sub(4)] super(-) and [Ga sub(2)Cl sub(7)] super( -) anions. All compounds were characterized by single-crystal X-ray diffraction, energy-dispersive electron-beam X-ray fluorescence spectroscopy, Raman vibrational spectroscopy and solid-state super(77)Se NMR spectroscopy. Supporting gas-phase and periodic DFT calculations allowed the assignments of the spectra and provided insights into the bonding situation of the hypervalent Sb atoms. GaCl sub(3)-based melts are a suitable reaction medium for the synthesis of polycationic clusters. A series of double-cube-shaped mixed antimony-chalcogen clusters such as (Sb sub(7)Se sub(8)) super( 5+) or (Sb sub(7)S sub(8)Cl sub(2)) super(3+) are synthesized and characterized by Raman and solid-state super(77)Se NMR spectroscopy. DFT calculations provide insights into the bonding situation and the spectroscopic properties.