Infrared spectral hole burning of 1 : 1 hydrogen-bonded complexes in solution

Transient picosecond infrared (IR) spectra of the OH and NH-stretch (v = 0 - 1) absorption bands of several hydrogen-bonded complexes have been invest igated. Solutions of 1:1 complexes of weak acids (methanol, triethylsilanol and pyrrole, < 0.1 mol/dm(3)) and bases (acetonitrile, pyridine and tetrah ydrofuran, < 2 mol/dm(3)) in CCl4 at 295 K were interrogated with IR excita tion and broadband probing. Lorentzian-shaped absorption bands are uniforml y bleached while those with near-Gaussian bandshapes produce transient spec tral holes. These results indicate a base functionality and hydrogen-bond s trength dependence for determining the broadening mechanisms of these absor ptions.