Bhowmick, Indrani; Newell, Brian S.; Shores, Matthew P. published their research in Dalton Transactions in 2021. The article was titled 《A systematic study of the influence of ligand field on the slow magnetic dynamics of Co(II)-diimine compounds》.Synthetic Route of C12H12N2 The article contains the following contents:
Herein the authors report heteroleptic Co(II) diimine complexes [Co(H2bip)2Cl2] (1), [Co(H2bip)2Br2] (2), [Co(H2bip)3]Br2·MeOH (3) and [Co(H2bip)2(Me2bpy)]Br2·(MeCN)0.5·(H2O)0.25 (4) (H2bip = 2,2′-bi-1,4,5,6-tetrahydropyrimidine, bpy = 2,2′-dipyridyl, Me2bpy = 4,4′-Me-2,2′-dipyridyl), purposefully prepared to enable a systematic study of magnetic property changes arising from the increase of overall ligand field from σ/π-donor chlorido in 1 to π-acceptor 4,4’Me-2,2’bpy in 4. The axial and rhombic anisotropy (D and E) of these compounds is sufficient to allow 1-4 to show field-induced slow relaxation of magnetization. The authors found as the effective ligand field is increased in the series, rhombicity (E/D) decreases, and the magnetic relaxation profile changes significantly, where relaxation of magnetization at a specific temperature becomes gradually faster. The authors performed mechanistic analyses of the temperature dependence of magnetic relaxation times considering Orbach relaxation processes, Raman-like relaxation and quantum tunnelling of magnetization (QTM). The effective energy barrier of the Orbach relaxation process (Ueff) is largest in 1 (19.2 cm-1) and gradually decreases in the order 1 > 2 > 3 > 4 giving a min. value in 4 (8.3 cm-1), where the Raman-like mechanism showed the possibility of different types of phonon activity below and above ~2.5 K. As a precursor of 1, the tetrahedral complex [Co(H2bip)Cl2] (1a) was also synthesized and structurally and magnetically characterized. 1A exhibits slow relaxation of magnetization under an applied d.c. field (1800 Oe) with a record slow relaxation time of 3.39 s at 1.8 K. In the experiment, the researchers used many compounds, for example, 4,4′-Dimethyl-2,2′-bipyridine(cas: 1134-35-6Synthetic Route of C12H12N2)
4,4′-Dimethyl-2,2′-bipyridine(cas: 1134-35-6) is used as a chemical Intermediate. It can be used for the determination of ferrous and cyanide compounds.Synthetic Route of C12H12N2 Furthermore, 4,4′-Dimethyl-2,2′-bipyridine is used in the synthesis of a series of o-phenanthroline-substituted ruthenium(II) complexes.