Electrochemistry of Heteroleptic Tris(phthalocyaninato) Rare Earth(III) Complexes

Abstract

The electrochemical characteristics of a series of heteroleptic tris(phthalocyaninato) complexes with identical rare earths or mixed rare earths (Pc)M(OOPc)M(OOPc) [M = Eu...Lu, Y; H 2 Pc = unsubstituted phthalocyanine, H 2 (OOPc) = 3,4,12,13,21,22,30,31-octakis(octyloxy)phthalocyanine] and (Pc)Eu(OOPc)Er(OOPc) have been recorded and studied comparatively by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) in CH 2 Cl 2 containing 0.1 M tetrabutylammonium perchlorate (TBAP). Up to five quasi-reversible one-electron oxidations and four one-electron reductions have been revealed. The half-wave potentials of the first, second and fifth oxidations depend on the size of the metal center, but the fifth changes in the opposite direction to that of the first two. Moreover, the difference in redox potentials of the first oxidation and first reduction for

Electron‐Donating Alkoxy‐Group‐Driven Synthesis of Heteroleptic Tris(phthalocyaninato) Lanthanide(III) Triple‐Deckers with Symmetrical Molecular Structure

“…(9) have been recorded in CDCl 3 at room temperature. The assignment of the spectra for the homodinuclear complexes 7 and 8 is straightforward because of the resolved multiplicity in the signals for the alkyl-chain protons and the availability of [(Pc)Y{Pc(OC 8 H 17 ) 8 }Y(Pc)] spectrum, [6] (13) suitable for X-ray diffraction analysis were obtained by diffusing hexane onto a solution of the compounds in toluene. These compounds crystallize in the triclinic system with a P1 space group.…”

“…[15,16] The heteroleptic tris(phthalocyaninato) rareearth-metal compounds in which two different phthalocyanine ligands are contained in one molecule are still scare and are limited to [(Pc)Lu{Pc(15C5) 4 }Lu(Pc)], [4] [ [5,6] and [7][8][9] reported very recently by either Ishikawa Satisfactory elemental analysis results have been obtained for all these newly prepared hetero-and homodinuclear lanthanide triple-decker complexes 1-8 and 9-15, which have good solubility in common organic solvents such as CHCl 3 , CH 2 Cl 2 , and toluene, after repeated column chromatography and recrystallization, Table 1. They have also been characterized by MALDI-TOF mass spectrometry (Table 1) The MALDI-TOF mass spectra of these compounds clearly showed intense signals for the molecular ion [M] + .…”

“…Accordingly, in these triple-decker molecules the close proximity of the three conjugated p-systems in a face-to-face configuration induces splitting of the doubly degenerate (e g ) LUMO and nondegenerate 4a u HOMO molecular orbitals of the monophthalocyanines. [6,19] This results in three pairs of doubly degenerate unoccupied frontier molecular orbitals (the bonding LUMO, second nonbonding LUMO, and third antibonding LUMO) and three nondegenerate occupied frontier orbitals (the third bonding HOMO, second nonbonding HOMO and first antibonding HOMO) in the triple-deckers. The splitting between the first HOMO and second HOMO of tripledecker increases with decreasing lanthanide radius, due to the increase in the ring-to-ring interaction.…”

“…[4] As part of the efforts to developing novel species of sandwich tetrapyrrole rare-earth-metal complexes, we have described the synthesis of a series of heteroleptic phthalocyaninato rare- . [5,6] By employing a similar procedure, Ishikawa and co-workers prepared the series of rare-earth-metal analogues…”

“…[1][2][3][4][5][6] Very recently, they have started to attract interest as they are good systems to study for the interaction between two 4f-electonic ions in an isolated environment, [7][8][9] in addition to the benzimidazole, pyridine, and dipicolinic acid rareearth-metal complexes with triple-helix structures. [10][11][12][13][14] The first tris(phthalocyaninato) rare-earth-metal compound was homoleptic [Y 2 (Pc) 3 ] reported in 1986 by Takahashi and Kasuga as a side-product in the synthesis of double-decker [Y(Pc) 2 ].…”