A C,S bonded quasi-two-coordinate chromium(ii) complex showing field-induced slow magnetic relaxation behaviour

Abstract

A C,S bonded quasi-two-coordinate Cr(II) complex, Cr(SAr*)2 (HSAr* = HSC6H3-2,6(C6H2-2,4,6-Pri3)2), has been successfully synthesized. Magnetic, high-frequency / field electron paramagnetic resonance (HF-EPR) experiments and ab initio calculation studies show that...

Synergy of Magnetic Anisotropy and Ferromagnetic Interaction Triggering a Dimeric Cr(II) Zero-Field Single-Molecule Magnet

“…The negative sign of the D values for 1 is consistent with that of those previously reported Cr II complexes (Table ). − …”

“…In this respect, among them, chromium, whose dominant isotopes have no nuclear spin, may be an ideal candidate. However, to this day, only a handful number of them are related to Cr II ions, like few multinuclear clusters and low-coordinate mononuclear complexes, and none of them show dynamic relaxation at zero dc field. − This is directly connected to the presence of the quantum tunneling of magnetization (QTM) effect which tends to degrade the performance of SMM and easily exists in cases exhibiting transverse magnetic anisotropy . In this respect, magnetic exchange coupling can both fairly weaken QTM between the ground states and dominate relaxation to produce through the thermal pathway .…”

Influence of lattice water molecules on the magnetization dynamics of binuclear dysprosium(iii) compounds: insights from magnetic andab initiocalculations

“…13 Therefore, researchers adopted fine-tuning methods including the change of the coordinated solvents, ligands, electrostatic environments and pH values to explore the magneto-structural relationships. [14][15][16][17] The existence of lattice solvents can exhibit influences on Dy 2 -SMM behaviors, due to the fact that weak intermolecular interactions may fine tune the local coordination geometries of Dy III centers. 18 Moreover, the lattice solvents can adjust the intermolecular distances between the Dy III centers and further alter the dipole-dipole interactions, thus affecting the relaxation processes of Dy 2 -SMMs.…”

How to enhance the effective spin-reversal barriers of two-coordinate Co(ii) imido complexes with [CoN]+ core? a theoretical investigation

“…In 2022, the highest record of T B,100s , the temperature at which the relaxation time τ = 100 s, was 72 K in mixed-valence di-lanthanide complexes (Cp iPr5 ) 2 Dy 2 I 3 with a thermal barrier to magnetic relaxation of 1631(25) cm −1 reported by Long et al 17 In general, rare-earth SMMs characterized with shielded 4f orbitals by the external ones and unquenched orbital angular momentum, L possess stronger magnetic anisotropies than transition–metal (TM) SMMs, which usually have quenched L . However, a series of two-coordinate TM compounds, such as Cr(SAr*) 2 , 18 Fe( ii )[C(SiMe 3 ) 3 ] 2 ( U eff = 181 cm −1 ), 19 FeL 2 (L = N(SiMe 3 )(Dipp), N(H)Ar′, N(H)Ar*), 19 [Fe( i )(C(SiMe 3 ) 3 ) 2 ] − ( U eff = 226 cm −1 ), 20 V{N-(SiMePh 2 ) 2 } 2 , 21 Cr{N(SiMe 2 Ph) 2 } 2 , 21 [Ni(MDABCO) 2 Cl 3 ]ClO 4 , 22 [(NHC)CoNDmp] ( U eff = 413 cm −1 ), 23 Co(C(SiMe 2 ONaphthyl) 3 ) 2 ( U eff = 450 cm −1 ), 24 [K(18-crown-6)][Fe{N(SiMe 3 ) 2 } 2 ], 25 [Co{κ 6 - N , N , N , N ′, N ′, N ′-PhB[ONC(Me)C 3 N 2 H] 3- }Cl] ( U eff = 152 cm −1 ), 26 and [Ni(NHC) 2 ]Br, 27 have remarkable magnetic performance and are excellent candidates of SMMs. Among them, Co II -based systems exhibit superior magnetic relaxation properties compared to the others.…”