George Brink

Studies in hydrogen-bonding: Association in methylamine using an empirical potential

Abstract The empirical potentials EPEN and EPEN/2 have been used to establish the structures of isolated hydrogen-bonded clusters in methylamine. The most stable form of the dimer has an open structure with high dipole moment, the most stable trimer has a cyclic structure with low dipole moment and the tetramer has a cyclic structure with zero dipole moment. The results are compared, and generally agree, with experimental findings on clusters of methylamine in the vapour state.

Infrared studies of solute-solvent interactions: The NH2 stretching bands of aniline in non-aqueous solvents

Abstract A study has been made of the NH 2 , ND 2 and NHD stretching frequencies of aniline in various solvents. The uncoupled NH and ND frequencies of —NHD are used to determine whether the NH bonds of the amino group, —NH 2 , are symmetric. For aniline in butyl ether, the NH band is split, indicating asymmetric NH bonds as a result of the solute-solvent interaction. Relationships between the symmetric and asymmetric NH 2 and ND 2 stretching vibrations are also useful for determining asymmetry in the amino group when it interacts with solvent molecules. A study of the integrated intensities of ν a (NH 2 ) and ν s (NH 2 ) of aniline in fourteen solvents gives an indication of the nature of the interaction. In particular, the role of the lone-pair electrons is discussed.

Infrared studies of water in crystalline hydrates: BaCl2·2H2O

Abstract The i.r. spectra of the OH and OD stretching vibrations of isotopically dilute HDO in barium chloride dihydrate have been studied at 28° and −175°. The spectra show that three of the OH groups of the water molecules form hydrogen bonds of similar strength while the fourth OH group is much more weakly bonded, in agreement with neutron diffraction studies on the crystal. The i.r. results indicate that the strongest hydrogen bond formed in this hydrate has the same enthalpy as the hydrogen bonds present in ice.

Infrared Studies of Water in Crystalline Hydrates: Ba(ClO 3 ) 2 ·H 2 O

Infrared studies of the uncoupled OH and OD vibrations of isotopically dilute HDO have given important information about the nature of water molecules in crystalline hydrates. The main advantage of studying the spectrum of dilute HDO in H2O or D2O is that vibrations are free of intramolecular and intermolecular coupling and are thus narrower and have simpler shapes.