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; H2Pc = 2, 3, 9, 10, 16, 17, 23, 24-octakis(4-methoxyphenoxy)phthalocyanine] with tervalent rare earths MIII[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 MIII[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 Pc2−. 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.