Infrared studies of water in complexes

The intramolecular coupling of the OH stretching vibrational frequencies are studied in binary mixtures (H2O + bases) and ternary mixtures (H2O + bases + CCl4). For water molecules partially H bonded with bases (1:1 complexes) this coupling decreases rapidly with the acceptor strength, the C2ν symmetry changing to Cs. In 2:1 complexes the C2ν symmetry is re-established, ν3 and ν1 undergo similar frequency shifts referred to unperturbed H2O. The force constants and vibrational modes of water in 1:1 complexes are calculated approximately. This paper shows that the frequency region between the unperturbed ν3 and the unperturbed (ν3+ν1)/2 is useful in determining the content of non H bonded OH groups.