Slow magnetic relaxation in the tetrahedral cobalt(II) complexes [Co(EPh)4]2− (EO, S, Se)

Magnetic anisotropy in two- to eight-coordinated transition–metal complexes: Recent developments in molecular magnetism

“…34 was the first mononuclear 3d transition-metal complex reported to exhibit SMM properties in a zero dc field [57]. M a n u s c r i p t Edited June 25 This compound is characterized by ZFS parameters of D = -74 cm -1 and |E| ≤ 0.01 cm -1 , which were estimated from the dc magnetic properties with an isotropic g-tensor, whereas the analysis considering an anisotropic g factor yielded D = -62(1) cm -1 [58]. The order of magnitude of D was confirmed by EPR spectroscopy.…”

“…34 illustrates the importance of combining Ising-type magnetic anisotropy (D < 0) and half-integer spin carriers (S = 3/2) to observe SMM properties in the absence of a dc field. The related complexes [Co II (EPh) 4 ] 2-(E = O, 35 and E = Se 36) were used to investigate the effects of the ligand field (by modulating the softness of E) on ZFS splitting [58]. Indeed, weak ligand fields were expected to enhance D with tetragonally-elongated coordination geometry (D 2d symmetry).…”

“…In the former case, the degenerate d xy and d x2-y2 pair of orbitals incorporates three electrons, which are the source of magnetic anisotropy. Detailed experimental and theoretical investigations have been performed using two mononuclear penta-coordinated complexes, i.e., [Ni(Me 6 tren)Cl]OTf (57) and [Ni(Me 6 tren)Br]Br (58), which incorporate Ni II in almost ideal TBP geometries (Fig. 20) [92].…”

Evidence of Slow Magnetic Relaxation in Co(AcO)2(py)2(H2O)2

“…The double well model holds up in the case of monometallic cobalt(II) SMMs with negative D values [9,[11][12][13][14][15][16][17][18][19], but the observation of similar behaviour in monometallic cobalt(II) complexes with positive D values [20][21][22] suggests that the picture is more complex. Indeed, slow relaxation in positive-D compounds is a phenomenon that is not yet fully understood-although attempts have been made to explain it [23,24].…”

Spectral, morphological, linear and nonlinear optical properties of nanostructured benzimidazole metal complex thin films

“…This can be assigned to 4 A 2 ! 4 T 1 (P) electronic transition [33]. The band observed in this region is the characteristic of tetrahedral structure and arises due to spin-orbit coupling of the T state.…”