IR absorption spectroscopic characteristics of peripherally substituted thiophenyl phthalocyanine in sandwich bis(phthalocyaninato) complexes

The IR spectra data for a series of thirteen rare earth double-deckers M[Pc(SPh)8]2 (M = Y, Ce⋯Lu, except La and Tm) have been collected and detailed characterized. The electronic absorption spectra showed that the Soret and Q bands are blue-shifted, and especially the Q bands at 705-726 nm clearly become stronger along with the decrease of rare earth ion radius. For MIII[Pc(SPh)8]2, the Infrared characteristic absorption peaks for the phthalocyanine anion radical [Pc(SPh)8]− were observed at 1311-1323 cm−1 as the strongest absorption bands, which can be ascribed to the pyrrole stretching. As for the Ce[Pc(SPh)8], the marker absorption bands at 1335 cm−1 was observed. In addition, the typical IR absorption bands of phthalocyanine radical anion [Pc(SPh)8]− move to the high energy as the decrease of rare earth metal ionic radius. These facts suggest that the π-π electron interaction in these double-deckers becomes stronger along with the lanthanide contraction.