52374-78-4Relevant academic research and scientific papers
Preparation, structural and spectroscopic characterisation of the salts M3X3AF6 (A = As or Sb, M = S or Se, X = Cl or Br) containing the novel sulfur-and selenium-halogen cations (X2MMMX)+
Brownridge, Scott,Cameron, T. Stanley,Passmore, Jack,Schatte, Gabriele,Way, Todd C.
, p. 2553 - 2570 (2007/10/03)
The salts X2MMMX(AF6) (A = As or Sb, M = S or Se, X = Cl or Br) were prepared quantitatively by the reaction of stoichiometric amounts of MX3AF6 and M or from stoichiometric amounts of M, X2 and AsF5 (M = S or Se; X = Br) in liquid SO2. They have been characterised by elemental analysis, single-crystal X-ray diffraction, Fourier-transform (FT)-Raman and 77Se FT-NMR spectroscopy. The crystal structures of X2MMMX(AsF6) consist of (X2MMMX)+ cations and AsF6- anions. The structure of the (X2MMMX)+ cation is dominated by an intracationic halogen-chalcogen contact and M-M bond alternation giving rise to a short M-M bond distance indicative of thermodynamically stable npπ-npπ (n = 3 or 4) bonds. Since the structure of these cations is different from those of (YM)2MY+ (Y = Me or C6F5), theoretical calculations were performed to understand these differences and the bonding in these cations. In the X2SSSX(AsF6) salts (X = Cl or Br) the structures of the cations are disordered and therefore exact bond distances could be not obtained. However, bond distances were estimated from their FT-Raman spectra and supported by molecular orbital calculations. The FT-Raman spectrum of Se2Br5AsF6 is reported.
