Infrared spectroscopic characteristics of mixed rare earth triple-decker complexes with phthalocyaninato and 5-(4-hydroxyphenyl)-10,15,20-tris(4-octyloxy)porphyrinato ligands.

Abstract The infrared (IR) spectroscopic data for a series of nine mixed rare earth triple-deckers M 2 III [TO(OH)PP](Pc) 2 ] [M = La⋯Dy, except Pm, Y and Ho⋯Lu; H 2 Por = 5-(4-hydroxyphenyl)-10,15,20-tris(4-octyloxyphenyl)porphyrin, Pc = unsubstituted phthalocyanine] with tervalent rare earths have been collected. For M 2 III [TO(OH)PP](Pc) 2 ], typical IR marker bands for the unsubstituted phthalocyanine dianion Pc 2− are strong bands at 1327–1329 cm −1 , and a weak band around 1370–1383 cm −1 . They can be assigned to pyrrole C C stretchings. The absence of Pc 2− another marker IR band around 1376 cm −1 demonstrates that the cerium metal ion in the IR spectrum of Ce 2 III [TO(OH)PP](Pc) 2 ] exists as intermediate valence state between III and IV. The IR spectra of these mixed triple-decker complexes reveal that the frequencies of pyrrole stretching, isoindole breathing, and aza stretchings are decreased sensitive to the rare earth ionic size, and remain basically unchanged along with the lanthanide contraction. These facts indicate that the π–π interactions in these mixed triple-deckers are weaker than those in the double-deckers.