PHOTOCHEMISTRY OF HYDROGEN BROMIDE ACETYLENE COMPLEXES IN SOLID KRYPTON

Hydrogen-bonded complexes between HBr and acetylene in inert gas matri ces were subjected to medium-pressure Hg lamp photolysis at 12 K. For HBr-acetylene, the major product was bromoacetylene, while vinyl bromi de was present in trace amounts. When HBr-perdeuterioacetylene and DBr -acetylene complexes were photolyzed, bromoacetylene, deuteriobromoace tylene, and the hydrogen exchange product, DBr(HBr)-C2HD, were the pri mary products. Partially deuterated vinyl bromides were present in tra ce amounts. In HBr-perdeuterioacetylene, the only isomer observed was cis-CDBr=CHD. Ln DBr-acetylene, both cis- and trans-CHBr=CHD were obse rved, In neither experiment was the 1,1 addition product formed. The r esults are interpreted in terms of the supramolecule model of complex photochemistry put forth by Abrash and Pimentel.