Westrup Kátia Cristina M, Boulon Marie-Emmanuelle, Totaro Pasquale, Nunes Giovana G, Back Davi F, Barison Andersson, Jackson Martin, Paulsen Carley, Gatteschi Dante, Sorace Lorenzo, Cornia Andrea, Soares Jaísa F, Sessoli Roberta
Departamento de Química, Universidade Federal do Paraná, Centro Politécnico, 81530-900, Curitiba-PR (Brazil).
Chemistry. 2014 Oct 13;20(42):13681-91. doi: 10.1002/chem.201403361. Epub 2014 Sep 8.
The selective replacement of the central iron(III) ion with vanadium(III) in a tetrairon(III) propeller-shaped single-molecule magnet has allowed us to increase the ground spin state from S=5 to S=13/2. As a consequence of the pronounced anisotropy of vanadium(III), the blocking temperature for the magnetization has doubled. Moreover, a significant remnant magnetization, practically absent in the parent homometallic molecule, has been achieved owing to the suppression of zero-field tunneling of the magnetization for the half-integer molecular spin. Interestingly, the contribution of vanadium(III) to the magnetic anisotropy barrier occurs through the anisotropic exchange interaction with iron(III) spins and not through single ion anisotropy as in most single-molecule magnets.
在一个四铁（III）螺旋桨状单分子磁体中用钒（III）选择性取代中心铁（III）离子，使我们能够将基态自旋态从S = 5提高到S = 13/2。由于钒（III）具有明显的各向异性，磁化的阻塞温度增加了一倍。此外，由于半整数分子自旋的磁化零场隧穿受到抑制，在母体同金属分子中几乎不存在的显著剩余磁化得以实现。有趣的是，钒（III）对磁各向异性势垒的贡献是通过与铁（III）自旋的各向异性交换相互作用产生的，而不像大多数单分子磁体那样通过单离子各向异性产生。
