Infrared studies of hydrogen-bonded systems
Methanol was initially reviewed and examined in the fundamental and overtone stretching regions of the infrared spectrum as a solute in inert solvents to produce a basis for studies into its role as a solvent. Interactions of methanol monomers with bifunctional secondary amines as cosolutes were then briefly studied. As a bulk solvent, the interactions of methanol with aprotic organic bases as cosolvents were studied at some length, firstly in the OH stretching region and then in the COH bending region. Spectra of the bulk solvent at low temperatures showed some trifunctionality of methanol, and data obtained from methanol/base systems were in good agreement with those from terniary inert solvent systems. Examination of the bending mode showed agreement with other results but was altogether fairly uninformative. COH bend region studies of MeOH-C10-4 and -I- solutions showed evidence of weak hydrogen bonds to the perchlorate ion as well as to the iodide ion, and the existence of solvent-shared ion-pairs. Examination of the HOH bending mode of water highlighted the 1:1 H2O / Base complexes --- difficult to observe using the OH stretching modes of water --- as well as the scavenging by the base of (OH)free groups present in bulk water. The monitoring of solely the frequency shifts from HOH bend spectra of H2O / salt solutions was uninstructive but, coupled with dissymmetry data, produced support for the results obtained from the OH stretching region. Evidence towards the possibility of doubly-bonded 1:1 water / perchlorate species was also suggested. Finally, the infrared bending mode for water / methanol mixtures produced results inconsistent with data obtained from the following aquomethanolic salt-solution studies and previous N.M.R. results concerning relative acidic and basic properties of water and methanol, but in agreement with results obtained from other techniques.