Magnetic relaxation behavior of a spatially closed dysprosium(III) phthalocyaninato double-decker complex

Binuclear Phthalocyanine‐Based Sandwich‐Type Rare Earth Complexes: Unprecedented Two π‐Bridged Biradical‐Metal Integrated SMMs

“…In particular, as shown in Figure S11 in the Supporting In-formation, the hysteresis loop for the biradical compound can be observed at temperatures up to 5 K. This, to the best of our knowledge, represents the highest hysteresis temperature that has ever been recorded for the sandwich-type tetrapyrrole-dysprosium SMMs. [6,18,19] The zero-field cooled (ZFC) and 1000 Oe field cooled (FC) susceptibility measurements for both 1 and 1' are in good accordance with those derived from the hysteresis loops, Figure S12 in the Supporting Information. In addition, a residual field of 0.95 m B and a coercive field of 200 Oe are observed at 2 K for the biradical sandwich compound 1, as compared with the zero residual and coercive fields observed for the nonradical 1' seems to confirm the origin of QTM suppression as the biradical intramolecular antiferromagnetic interaction observed in 1, Figure 3 and S10 in the Supporting Information.…”

“…Interestingly, the energy barrier observed for 1' is completely in accord with that for the mono-dysprosium-containing reduced form of the bis(phthalocyaninato) double-decker complex [NA C H T U N G T R E N N U N G (C 4 H 9 ) 4 ] + ·[Dy{PcA C H T U N G T R E N N U N G (OC 2 H 5 ) 8 } 2 ] À , U eff = 28.0 cm À1 (40 K), [6d] clearly revealing the origin of the magnetic behavior of 1' from the single dysprosium ion. This, in combination with the strong QTM observed for the mono-radical double-decker species Dy[PcA C H T U N G T R E N N U N G (OC 4 H 9 ) 8 ] 2 with the Dy III ion also employing a nearly D 4d local symmetry, [19] seems to suggest close association of the significant suppression of QTM in the biradical sandwich compound 1 involving the biradical in intramolecular antiferromagnetic interaction. Further support for this point comes from the significantly larger energy barrier found for t 1, 47 cm À1 , in comparison with those of tris(phthalocyainato) and tetrakis- Typical SMM nature of 1 and 1' was further evidenced by the butterfly-shaped hysteresis loops observed for both species at 2 K, Figure 3 and S10 in the Supporting Information.…”

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

“…It is clear that electron-withdrawing substituents at the periphery of phthalocyanine ligands are helpful for suppressing the QTM effect, thereby enhancing the energy barrier for multikis(phthalocyaninato) lanthanide SMMs [45,46]. By contrast, the effects of electron-donating substituents on homoleptic bis(phthalocyaninato) lanthanide double-decker compounds remain unclear [45,[48][49][50]56]. Compared with the Ln-Y or Y-Ln multiple-decker species, short-or long-range intramolecular f-f interactions in the bis-lanthanide multiple-decker compounds are usually beneficial for enhancing the energy barrier height of spin reversal and the blocking temperature (Scheme 3E) [60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76].…”

Molecular Design for Single-molecule Magnetism of Lanthanide Complexes

“…35 The effects of intramolecular ff interaction on the rate of QTM are complicated. 36 In heteroleptic triple-decker [(Pc)Tb(Pc)-Tb(Pc (29) with an octabutoxyphthalocyanate and two unsubstituted phthalocyanates, the lanthanide ions exist along the fourfold symmetry axis with a separation of ca. 3.6 ¡ (Figure 10a).…”