INFRARED MATRIX-ISOLATION STUDIES OF MOLECULAR-INTERACTIONS - ALKYNES WITH HALIDE ANIONS

The matrix isolation technique has been combined with the salt/molecule technique to isolate and characterize the products formed between a series of 1-alkynes and the cesium halides. When acetylene was employed, hydrogen-bonded complexes of the form C2H2...X- were formed, with frequency shifts of the hydrogen-bonded C-H group which were much greater than for analogous complexes with neutral bases. When alkynes containing electron-withdrawing groups were employed, complexes involving nucleophilic attack rather than hydrogen bonding were observed, although for the CsF/CF3CCH system evidence was obtained for both types of complexes. When an alkyne containing an electron-donating group was used, only the hydrogen-bonded complex was observed.