μ2-Halogenokomplexe von N-Iodsuccinimid. Die Kristallstrukturen von PPh4[X(N-Iodsuccinimid)2] · CH3CN mit X = Cl, Br, / μ2-Halogeno Complexes of N-Iodosuccinimide. The Crystal Structures of PPh4[X(N-Iodosuccinimide)2] · CH3CN with X = Cl, Br, I

Abstract

The μ2-halogeno complexes PPh4[X(N-Iodosuccinimide)2] · CH3CN with X = CL Br, I have been prepared by reactions of N-Iodosuccinimide with the corresponding tetraphenylphos- phonium halides PPh4X in acetonitrile solutions. The compounds form pale yellow crystal needles, which were characterized by IR spectroscopy and by crystal structure determinations. PPh4[Cl(N-Iodosuccinimide)2] · CH3CN (1): Space group Pna21, Z = 4, 4461 observed unique reflections. R = 0.027. Lattice dimensions at -60 °C: a = 1840.5(9), b = 2589(1), c = 728.2(4) pm. PPh4[Br(N-Iodosuccinimide)2] · CH3CN (2): Space group Pna21 Z = 4, 4284 observed unique reflections, R = 0.034. Lattice dimensions at -70 °C: a = 724.8(4), b = 1838.6(9), c = 2601(1) pm. PPh4[I(N-Iodosuccinimide)2] · CH3CN (3): Space group Pna21, Z = 4, 5775 observed unique reflections. R = 0.031. Lattice dimensions at -60 °C: a = 1849.2(9). b = 2644(1), c = 730.3(4) pm. 1-3 are isotypical. There structures consist of PPh4 + ions, including acetonitrile molecules without bonding interactions, and anions [X(iodosuccinimide)2]-, in which the halide ions X- are coordinated bv the iodine atoms of the N-iodosuccinimide molecules. The bond angles I··· X···I range from 90.13(4)° (X = Cl) and 88.84(3)° (X = Br) to 87.83(3)° (X = I). The bond angles N- I ··· X are nearly linear.