Interaction of the electrophilic bis(pentafluorophenyl)iodonium cation [(C6F5)2I]+ with the ambident pseudohalogenide anions [SCN]− and [CN]−

The iodonium pseudohalide compounds, [(C6F5)2I][X] (X = SCN and CN) were synthesized by means of fluoride substitution in [(C6F5)2I][F] with the Lewis acidic reagents (CH3)3Si–NCS and (CH3)3Si–CN. The isolated iodonium pseudohalides are intrinsically unstable solids. Decomposition resulted in equimolar amounts of C6F5I and C6F5SCN or C6F5I and C6F5CN, respectively. In case of [(C6F5)2I][SCN] single crystals could be grown from CH2Cl2. The crystal structure revealed a dimer with an eight membered ring formed by two ambident anions bridging the iodine atoms of two cations by N and S coordination. The favored dimerization of [(C6F5)2I][SCN] and [(C6F5)2I][CN] in the gas phase is supported by ab initio computations.