Highly Reduced Double-Decker Single-Molecule Magnets Exhibiting Slow Magnetic Relaxation

Abstract

F64Pc2Ln (1Ln, Ln = Tb or Lu) represent the first halogenated phthalocyanine double-decker lanthanide complexes, and 1Tb exhibits single-molecule magnet properties as revealed by solid-state magnetometry. The fluorine substituents of the phthalocyanine rings have a dramatic effect on the redox properties of the F64Pc2Ln complexes, namely, a stabilization of their reduced states. Electrochemical and spectroelectrochemical measurements demonstrate that the 1Tb(-/2-) and 1Tb(2-/3-) couples exhibit redox reversibility and that the 1Tb(-), 1Tb(2-) and 1Tb(3-) species may be prepared by bulk electrolysis in acetone. Low-temperature MCD studies reveal for the first time magnetization hystereses for the super-reduced dianionic and trianionic states of Pc2Ln.

Molecular single-ion magnets based on lanthanides and actinides: Design considerations and new advances in the context of quantum technologies

“…10b). This was attributed to the suppression of QTM in the even charged redox states because of strong coupling between the lanthanide f-orbital and the radical ligand -orbital [97]. (40) and [Dy(H2dabph)(Hdabph)](NO3)2 (41, dabph = 2,6-diacetylpyridinebis(benzoic acid hydrazine)) differ only through the deprotonation of a ligand amino nitrogen (Fig.…”

Single-molecule magnetism of tetrapyrrole lanthanide compounds with sandwich multiple-decker structures

“…43. Copyright 2010 Journal of American Chemistry Society.Two further studies have addressed the enhancement of the SMM properties associated with the longitudinal contraction effect[43,44], where the magnetization properties of a small quantity of the double-decker SMM sample in frozen dilute solution was characterized by magnetic circular dichroism (MCD) spectroscopy at low temperature. A comparative study of the magnetization hysteresis of [(Pc 3 )Tb(Pc 3 )] -/0/+ (11a-c) using this method demonstrated the excellent SMM property of the cationic form 11c due to the longitudinal contraction effect[43].…”

“…A much smaller deviation from the D 4d symmetry (approximate twist angle of 45) is helpful for suppressing the QTM in these SMM systems in a zero dc magnetic field (Scheme 3A). In addition to the change in the oxidation state of the double-decker compounds from negative to positive valence, the longitudinal contraction in the coordination sphere of the bis(tetrapyrrole) lanthanide SMM (Scheme 3B), i.e., the decrease in the inter-planar N4-N4 distance, is helpful for improving the SMM properties in terms of the energy barrier and blocking temperature[40][41][42][43][44][45]. Lanthanide-organic radical (f-π) interactions are helpful for enhancing the SMM properties according to studies of neutral unprotonated bis(phthalocyaninato) and bis(porphyrinato) lanthanide SMMs (Scheme 3C)…”

Highly Thermostable, Non‐oxidizable Indium, Gallium, and Aluminium Perfluorophthalocyanines with n‐Type Character

“…According to some sources phthalocyanines account for approximately 25 %o f the world's production of dyes andp igments. [6] The planar phthalocyanine scaffold, with 16 peripheralC ÀHb onds that can be substituted with different functionalities as well as an abilityt oh ost nearly every metal in variouso xidation states, has ap lethora of different structuresa nd applications. [7,8] Perfluorophthalocyaninesa re an interesting variant of substituted phthalocyanines (Figure 1).…”

“…[9] We report herein perfluorinated phthalocyaninesw ith the PcF 64 scaffold incorporatingt hree-valentm etals, namely indium, gallium,a nd aluminium.S of ar PcF 64 complexes of zinc, cobalt, copper, magnesium, ruthenium, iron, vanadium oxide (V = O), terbium,a nd lutetium as well as metal-free PcF 64 have been reported. [10][11][12][13][14][15][16][17][18] The presence of as many as 64 fluo-rine atoms per phthalocyanine molecule (MPcF 64 ,i nw hich M = metal) inevitably affects its electronic properties. The eight fluoro substituents attached to the aromatic rings of the phthalocyanine participate in p-back-bonding, whereas the eight perfluoroisopropyl groups (i-C 3 F 7 )a re not conjugated with the aromatic system.F rom the viewpoint of their chemical properties, phthalocyanines with the PcF 64 scaffold resemble Teflon (chemical robustness, resistancet oo xidation and oxygenation,t hermals tability, resistance to photodegradation).…”