Infrared studies of water in complexes

Abstract

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 C_2ν symmetry changing to C_s. In 2:1 complexes the C_2ν 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.