1609084-07-2Relevant academic research and scientific papers
Magnetic properties of 1:2 mixed cobalt(II) salicylaldehyde schiff-base complexes with pyridine ligands carrying high-spin carbenes (S car = 2/2, 4/2, 6/2, and 8/2) in dilute frozen solutions: Role of organic spin in heterospin single-molecule magnets
Karasawa, Satoru,Nakano, Kimihiro,Yoshihara, Daisuke,Yamamoto, Noriko,Tanokashira, Jun-Ichi,Yoshizaki, Takahito,Inagaki, Yuji,Koga, Noboru
, p. 5447 - 5457 (2014/06/23)
The 1:2 mixtures of Co(p-tolsal)2, p-tolsal = N-p-tolylsalicylideniminato, and diazo-pyridine ligands, DXpy; X = 1, 2, 3l, 3b, and 4, in MTHF solutions were irradiated at cryogenic temperature to form the corresponding 1:2 cobalt-carbene complexes Co(p-tolsal)2(CXpy) 2, with Stotal = 5/2, 9/2, 13/2, 13/2, and 17/2, respectively. The resulting Co(p-tolsal)2(CXpy)2, X = 1, 2, 3l, 3b, and 4, showed magnetic behaviors characteristic of heterospin single-molecule magnets with effective activation barriers, U eff/kB, of 40, 65, 73, 72, and 74 K, for reorientation of the magnetic moment and temperature-dependent hysteresis loops with a coercive force, Hc, of ～0, 6.2, 10, 6.5, and 9.0 kOe at 1.9 K, respectively. The relaxation times, τQ, due to a quantum tunneling of magnetization (QTM) were estimated to be 1.6 s for Co(p-tolsal)2(C1py)2, ～2.0 × 103 s for Co(p-tolsal)2(C2py)2, and >105 s for Co(p-tolsal)2(CXpy)2; X = 3b, 3l, and 4. In heterospin complexes, organic spins, carbenes interacted with the cobalt ion to suppress the QTM pathway, and the τQ value increased with increasing the Stotal values.
