Preparation and crystal structure of [AsPh₄]₂[(WCl₅)₂{µ-NC(CF₃)₂N}]

The reaction of WCl3N with hexafluoroacetone in acetonitrile in the presence of a catalytic amount of triethylamine, followed by the addition of tetraphenylarsonium chloride, yields orange crystals of [AsPh4]2[(WCl5)2{µ-NC(CF3)2N}]. The X-ray structure [space group C2/c, a= 2 511.3(12), b= 1 194.5(10), c= 1 950.6(9) pm, β= 102.31(5)°, Z= 4, and R= 0.064 for 1 933 unique observed reflections] shows that the anion lies on a crystallographic two-fold axis through the central carbon atom; there is a short WN bond [174.3(15) pm] and the WN–C unit is almost linear [176.9(14)°].