Cobalt(II) Complexes as Single-Ion Magnets

The Structural and Magnetic Properties of FeII and CoII Complexes with 2-(furan-2-yl)-5-pyridin-2-yl-1,3,4-oxadiazole

“…With the aim to resolve the ambiguity in fitted parameters from DC magnetic data, the multi-reference ab initio calculations based on the state-averaged complete active space self-consistent field method (SA-CASSCF) were performed for both complexes 1 and 2. Herein, the ORCA software package [40,41] was used for these CASSCF calculations with the active space defined as six electrons in five d-orbitals, CAS (6,5) for Fe II complex 1 and seven electrons in five d-orbitals, CAS (7,5), for Co II complex 2. In addition, the dynamic electronic correlation was handled by using the N-electron valence state perturbation theory (NEVPT2) [42][43][44].…”

“…Therefore, the magnetic properties of 3d elements are of much interest to the scientific community. Among all of the 3d metals, Co(II) possesses great predispositions for the formation of compounds exhibiting SMM behavior due to relatively large spin-orbit coupling and the possibility to vary the coordination numbers from 2 to 8 [6]. Likewise, Fe(II) ranks among elements whose compounds are commonly known for SCO behavior [7].…”

“…This procedure induces formation of elongated transparent colourless crystals and yield 78%. EA (calc.%) for C6 H 7 N 3 O (FW = 137.14): C, 52.55, H, 5.14, N, 30.64, Found: C, 52.34, H, 5.36, N, 30.49. FT-IR (mid ATR,v/cm −1 ): 3288 v(N-H), 3210 v(NH), 3017 v(C-H arom ), 1671 v(C=O), 1622 v(NH 2 ), 1593 v(C=C, C=N), 1568 v(C=C, C=N), 1518 v(C=C, C=N, NH 2 ), 1433 v(C=C, C=N), 1123 v(C-N), 999 v(ring, pyridine), 819 v(C-H arom ), 750 v(C-H arom ), 620 v(ring, pyridine), 410 v(ring, pyridine).…”

Novel tetrahedral cobalt(ii) silanethiolates: structures and magnetism

“…In this area, mononuclear coordination complexes based on transition metals are promising due to properties they exhibit as single-molecule magnets (SMMs), also referred to as single-ion magnets (SIMs). [1][2][3][4][5] It is an intriguing group of compounds that is able to retain spin direction aer the removal of an external magnetic eld, and this particular feature is important to improving data storage and quantum computing devices. 6 The essential attribute of SIM complexes is a single-ion magnetic anisotropy, which generates an energy barrier for spin reversal and many works are aimed at nding the principles of its controlled modication.…”

Field-induced slow relaxation of magnetization in the S = 3/2 octahedral complexes trans-[Co{(OPPh2)(EPPh2)N}2(dmf)2], E = S, Se: effects of Co–Se vs. Co–S coordination

“…30 Complexes of Co(II) constitute the largest family of 3dmetal-based complexes showing slow relaxation of their magnetization. 22,31 It should be stressed that the tetrahedral S = 3/2 (PPh 4 ) 2 [Co(SPh) 4 ] complex 32,33 bearing a Co(II)S 4 core, was the first mononuclear 3d metal complex to exhibit slow relaxation of its magnetization in the absence of a Direct Current (DC) magnetic field. [34][35][36][37] Along these lines, tetrahedral [Co{(EP i Pr 2 ) 2 N} 2 ], E = S, 38 Se, 38 Te, 39 complexes, bearing dichalcogenidoimidodiphosphinato ligands 40 and Co(II)E 4 cores, exhibit slow relaxation of their magnetization, which was also observed in the absence of DC magnetic field for the E = Se, Te, complexes.…”