250. The frequencies and intensities of the N–H stretching vibrations in primary amines. Part II. Polycyclic aromatic amines

peri Interaction in Naphthalene Derivatives

“…That there is in all these cases some sp2 character to the N-H bonds in aromatic amines is shown by the higher values of in them as compared to that in cyclohexylamine. The variations noticed in antisymmetric N-H stretching vibrations and intensities are also attributed to steric effects (185) in peri amines. The exceptional behavior of 3-aminopyrene noticed here has been also pointed out in another investigation (199).…”

“…Elliott and Mason (185) and Krueger (356) have studied the N-H stretching frequencies and intensities of hindered and unhindered polycyclic aromatic amines.…”

“…Elliott and Mason (185) determined the position and intensity of vaa of the N-H stretching vibration bands in the 3400-cm-1 region for a series of such amines. and the estimated HNH angles ( ) in these amines.…”

Structural Characterization and Surface Modification of Evaporated Thin Films of 5,5‘‘‘-Bis(aminomethyl)-2,2‘:5‘,2‘‘:5‘‘,2‘‘‘-quaterthiophene and Its Dihydrochloride

“…The spectroscopic features in the wavenumber region around 3000 cm -1 most prominently reflect the difference of terminal groups (amine or amine hydrochloride). It is well-established that amino compounds exhibit two NH-associated modes: antisymmetric ν as (NH) and symmetric ν s (NH). , The ratio of ν s to ν as has been reduced theoretically to ν s /ν as = 0.98 for various amino compounds . The corresponding ratio for the doublet peaks occurring at 3328 and 3276 cm -1 in 1a is ν s /ν as = 3276/3328 = 0.984.…”

“…It is well-established that amino compounds exhibit two NH-associated modes: antisymmetric ν as (NH) and symmetric ν s (NH). 25,26 The ratio of ν s to ν as has been reduced theoretically to ν s /ν as ) 0.98 for various amino compounds. 27 The corresponding ratio for the doublet peaks occurring at 3328 and 3276 cm -1 in 1a is ν s /ν as ) 3276/3328 ) 0.984.…”