Vibrations Of Pyrrole Research Articles

Vibrations of pyrrole, N-substituted pyrroles, and their cations

The vibrations of pyrrole, N-deuteropyrrole, N-fluoropyrrole, N-aminopyrrole and N-methylpyrrole are studied. The evolution of the vibrational wavenumbers of pyrrole is examined, as the mass of the nitrogen-bonded hydrogen atom is artificially increased. It is found that some vibrations are very sensitive to the mass of the substituent bonded to the nitrogen, and this can be viewed as vibrations mixing as that mass increases; however, these mixings stablilize by the time a mass of 14 mu is reached. A consistent numbering scheme for the ring-localized vibrations of N-substituted pyrroles is then put forward. A discussion of the vibrations of the cations of pyrrole and N-substituted pyrroles is then presented. Calculated vibrational wavenumbers are compared to experimental ones for pyrrole, N-deuteropyrrole and N-methylpyrrole, as well as the pyrrole cation.

Infrared spectroscopic characteristics of octa-substituted bis(phthalocyaninato) rare earth complexes peripherally substituted with (4-methoxy)phenoxy derivatives

The infrared (IR) spectroscopic data for a series of 15 rare earth double-deckers M[Pc(MeOPhO) 8] 2 [M = Y, La, …, Lu, except Pm; H 2Pc = 2, 3, 9, 10, 16, 17, 23, 24-octakis(4-methoxyphenoxy)phthalocyanine] with tervalent rare earths M III[Pc(MeOPhO) 8] 2 (M = Y, La, …, Lu except Ce and Pm) and intermediate-valent cerium Ce[Pc(MeOPhO) 8] 2 have been collected with resolution of 2 cm −1. For M III[Pc(MeOPhO) 8] 2, typical IR marker band of the monoradical anion Pc(MeOPhO) 8 − shows characteristic absorption band whose frequency linearly varies in the range from 1313 cm −1 as a weak band for La[Pc(MeOPhO) 8] 2 to 1324 cm −1 as a medium band for Lu[Pc(MeOPhO) 8] 2 along with the decrease of rare earth ionic size. For Ce[Pc(MeOPhO) 8] 2, a weak band at 1324 cm −1 with contribution from pyrrole stretching was the marker IR band of phthalocyanine dianion Pc 2−. In conclusion, all the metal size-dependent IR absorptions should be contributed primarily from the vibrations of pyrrole, isoindole stretching, breathing or deformation or aza stretching of the Pc ring.