Enhanced Single‐Chain Magnet Behavior via Anisotropic Exchange in a Cyano‐Bridged Mo^III–Mn^II Chain

Abstract

Anisotropic magnetic exchange is of great value for the design of high performance molecular nanomagnets. In the present work, enhanced single‐chain magnet (SCM) behavior is observed for a MoIII–MnII chain that exhibits anisotropic magnetic exchange. Self‐assembly of the pentagonal bipyramidal [Mo(CN)7]4− anion and the MnII unit with a tridentate ligand results in a neutral double zigzag 2,4‐ribbon structure which exhibits SCM behavior with a high relaxation barrier of 178(4) K. Open magnetic hysteresis loops are observed below 5.2 K, with a coercive field of 1.5 T at 2 K. Interestingly, this SCM can be considered to be a result of a step‐wise process based on our previously reported Mn2Mo single‐molecule magnets (SMMs).

Magnetic anisotropy of transition metal and lanthanide ions in pentagonal bipyramidal geometry

“…38 Similarly, discrete or 1-D derivatives involving PBP [Mo(CN) 7 ] 4À and Mn II were found to behave as SMM or SCM but this is the case only when Mn is connected to the CN-ligands in the apical positions of Mo III . [39][40][41][42] The actual origin of magnetic anisotropy exhibited by these polynuclear species results from anisotropic Mo-Mn exchange interactions. 31 The same applies for the 5d derivative [Re(CN) 7 ] 3À in PBP geometry.…”

Magnetodielectric Response in a Layered Mixed-Valence Ferrimagnetic Molecular Compound

“…This frequency dependence sheds light on the existence of slow magnetic relaxation behavior. 33,34 For the low temperature region (25−35 K), the best fit is achieved by considering relaxation in accordance with the Arrhenius law, τ = τ 0 exp(−U eff /kT). The fitting results for this low temperature region are U eff = 462 (±1) K and τ 0 = 1.86 × 10 −10 s for 1 (Figure S7, Table S5).…”

Asymmetric Coordination Toward a Photoinduced Single‐Chain Magnet Showing High Coercivity Values

“…However, after the 808‐nm light irradiation, the in‐phase ( χ ′) and out‐of‐phase ( χ ′′) components exhibited strong frequency dependence for temperatures ranging from 4.5 to 7.0 K (Figure 3). The Mydosh parameter defined as Φ= (Δ T P / T P )/Δ(lg(2π f )) ( T P : peak temperature of χ ′′ vs. T plot) was 0.14, which fell in the expected range for SCMs and precluded the possibility of spin‐glassy behavior [4b, 12] . Furthermore, the extracted relaxation time τ vs. T −1 plot obeyed the Arrhenius law, yielding an energy barrier Δ E / k B of 101 K (Figure S13).…”