A synthetic protocol was developed that involves the transmetalation of a mono-dysprosium–[1]ferrocenophane complex with DyX3 (X = Cl– or I–) to afford [Dy3Fc6Li2(THF)2]−, featuring a rare linear arrangement of magnetically anisotropic Dy3+ ions. The close spatial inter-lanthanide proximity, in combination with μ2-bridging sp2-hybridized CCp groups, enforces significant magnetic coupling and results in hard single-molecule magnet (SMM) behavior, with an effective barrier to magnetization reversal of up to 268 cm–1. Our results highlight the versatility of lanthanide metallocenophane architectures toward the development of novel multinuclear SMM frameworks.

We present the first examples of CO2 electro-reduction catalysts that feature charged imidazolium groups in the secondary coordination sphere. The functionalized Lehn-type catalysts display significant differences in their redox properties and improved catalytic activities as compared to the conventional reference catalyst. Our results suggest that the incorporated imidazolium moieties do not solely function as a charged tag but also alter mechanistic aspects of catalysis.

The first example of a lanthanide metallocenophane complex has been isolated as [Li(THF)4][DyFc3Li2(THF)2] (1). The molecular structure of complex 1 differs dramatically from those of main group and transition metal ferrocenophane complexes and features a distorted trigonal prismatic geometry around the Dy(III) ion and close intramolecular Dy···Fe distances. Furthermore, complex 1 exhibits all characteristics of a soft single-molecule magnet.

Single-molecule magnets (SMMs) are considered viable candidates for next-generation data storage and quantum computing. Systems featuring switchability of their magnetization dynamics are particularly interesting with respect to accessing more complex logic gates and device architectures. Here we show that transition metal based redox events can be exploited to enable reversible switchability of slow magnetic relaxation of magnetically anisotropic lanthanide ions. Specifically, we report anionic homoleptic bis-diamidoferrocene complexes of Dy3+ (oblate) and Er3+ (prolate) which can be reversibly oxidized by one electron to yield their respective charge neutral redox partners (Dy: [1]−, 1; Er: [2]−, 2). Importantly, compounds 1 and 2 are thermally stable which allowed for detailed studies of their magnetization dynamics. We show that the Dy3+[1]−/1 system can function as an “on”/“off” or a “slow”/“fast” redox switchable SMM system in the absence or presence of applied dc fields, respectively. The Er3+ based [2]−/2 system features “on”/“off” switchability of SMM properties in the presence of applied fields. Results from electrochemical investigations, UV-vis-NIR spectroscopy, and 57Fe Mössbauer spectroscopy indicate the presence of significant electronic communication between the mixed-valent Fe ions in 1 and 2 in both solution and solid state. This comparative evaluation of redox-switchable magnetization dynamics in low coordinate lanthanide complexes may be used as a potential blueprint toward the development of future switchable magnetic materials.

We utilized a rigid ligand platform PyCp22− (PyCp22− = [2,6-(CH2C5H3)2C5H3N]2−) to isolate dinuclear Dy3+ complexes [(PyCp2)Dy-(μ-O2SOCF3)]2 (1) and [(PyCp2)Dy-(μ-Cl)]2 (3) as well as the mononuclear complex (PyCp2)Dy(OSO2CF3)(thf) (2). Compounds 1 and 2 are the first examples of organometallic Dy3+ complexes featuring triflate binding. The isolation of compounds 1 and 3 allows us to comparatively evaluate the effects of the bridging anions on the magnetization dynamics of the dinuclear systems. Our investigations show that although the exchange coupling interactions differ for 1 and 3, the dynamic magnetic properties are dominated by relaxation via the first excited state Kramers doublet of the individual Dy sites. Compounds 1 and 3 exhibit barriers to magnetization reversal (Ueff = 49 cm−1) that can be favorably compared to those of the previously reported examples of [Cp2Dy(μ-Cl)]2 (Ueff = 26 cm−1) and [Cp2Dy(thf)(μ-Cl)]2 (Ueff = 34 cm−1).

The reaction of Dy(N(Si(CH3)3)2)3 with three equivalents of HW(CO)3Cp (Cp = cyclopentadienyl) furnished the first structurally characterized isocarbonyl complex of Dy3+, [{CpW(CO)2(μ-CO)}3Dy(thf)5] (1). Solid dilution via cocrystallization with the isostrucutral Y3+ analogue of 1 allowed for the observation of temperature dependent signals in the out-of-phase component of the ac magnetic susceptibility in the presence of an applied dc field. An effective barrier to magnetization reversal of 12.6 cm−1 could be extracted for compound 1 under these conditions.

We utilized a rigid ligand platform PyCp22− (PyCp22− = [2,6-(CH2C5H3)2C5H3N]2−) to isolate dinuclear Dy3+ complexes [(PyCp2)Dy-(μ-O2SOCF3)]2 (1) and [(PyCp2)Dy-(μ-Cl)]2 (3) as well as the mononuclear complex (PyCp2)Dy(OSO2CF3)(thf) (2). Compounds 1 and 2 are the first examples of organometallic Dy3+ complexes featuring triflate binding. The isolation of compounds 1 and 3 allows us to comparatively evaluate the effects of the bridging anions on the magnetization dynamics of the dinuclear systems. Our investigations show that although the exchange coupling interactions differ for 1 and 3, the dynamic magnetic properties are dominated by relaxation via the first excited state Kramers doublet of the individual Dy sites. Compounds 1 and 3 exhibit barriers to magnetization reversal (Ueff = 49 cm−1) that can be favorably compared to those of the previously reported examples of [Cp2Dy(μ-Cl)]2 (Ueff = 26 cm−1) and [Cp2Dy(thf)(μ-Cl)]2 (Ueff = 34 cm−1).