Photochemistry of Hydrogen Iodide-Acetylene Complexes in Solid Krypton

Article abstract of DOI:10.1021/j100352a035

Hydrogen iodide-acetylene complexes in a krypton matrix at 12 K have been photolyzed with a medium-pressure mercury lamp.Infrared spectra identify products vinyl iodide and iodoacetylene.When HI*C2D2 complexes are photolyzed, isotopic exchange occurs to produce DI*HCCD.Growth curves show that all three are primary products.As well, the growth curves show secondary photolysis of vinyl iodide and DI*HCCD, but apparently production and secondary photolysis of vinyl iodide only catalyze isotopic exchange.The growth curves obtained for HCCI and DCCI from HI*C2D2 differ from those obtained from DI*C2H2.Short photolysis of HI*C2D2 gives almost exclusively HD*DCCI whereas short photolysis of DI*C2H2 gives HD*HCCI.Thus the hydrogen atom in the hydrogen iodode always ends up in the molecular hydrogen product.We conclude that photolytic production of iodoacetylene involves hydrogen atom abstraction from acetylene by the energetic hydrogen iodide.