Comparison of the Magnetic Anisotropy and Spin Relaxation Phenomenon of Dinuclear Terbium(III) Phthalocyaninato Single- Molecule Magnets Using the Geometric Spin Arrangement.
Herein we report the synthesis and characterization of a dinuclear Tb single-molecule magnet (SMM) with two [TbPc] units connected via a fused-phthalocyani-nato ligand. The stable and robust complex [(obPc)Tb(Fused-Pc)Tb(obPc)] (l) was characterized by using synchrotron radiation measurements and ot...
| Publicado en: | Journal of the American Chemical Society Vol. 140; no. 8; pp. 2995 - 3008 |
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| Autores principales: | , , , , , , , , , |
| Formato: | Artículo |
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American Chemical Society
2/28/2018
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=128315300&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 128315300 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 2/28/2018 vid: 140 iid: 8 pid: 997 pub: American Chemical Society artinfo: ui: 128315300 10.1021/jacs.7b12667 ppf: 2995 ppct: 13 formats: tig: atl: Comparison of the Magnetic Anisotropy and Spin Relaxation Phenomenon of Dinuclear Terbium(III) Phthalocyaninato Single- Molecule Magnets Using the Geometric Spin Arrangement. aug: au: Morita, Takaumi Katoh, Keiichi Breedlove, Brian K. Yamashita*, Masahiro Enders, Markus Damjanovic, Marko Lan, Yanhua Wernsdorfer, Wolfgang Kitagawa, Yasutaka Yasuda, Nobuhiro affil: Department of Chemistry, Graduate School of Science, Tohoku University, 6-3, Aramaki-Aza-Aoba, Aoba-ku, Sendai, Miyagi 980-8578, Japan WPI Research Center, Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan School of Materials Science and Engineering, Nankai University, Tianjin 300350, China Department of Cell Biology, New York University Medical Center, New York, New York, U.S.A su: Magnetic anisotropy Chemical synthesis Coupling reactions (Chemistry) Density functional theory Quantum tunneling composites sug: subj: Magnetic anisotropy Chemical synthesis Coupling reactions (Chemistry) Density functional theory Quantum tunneling composites ab: Herein we report the synthesis and characterization of a dinuclear Tb single-molecule magnet (SMM) with two [TbPc] units connected via a fused-phthalocyani-nato ligand. The stable and robust complex [(obPc)Tb(Fused-Pc)Tb(obPc)] (l) was characterized by using synchrotron radiation measurements and other spectroscopic techniques (ESI-MS, FT-IR, UV). The magnetic couplings between the Tb ions and the two π radicals present in 1 were explored by means of density functional theory (DFT). Direct and alternating current magnetic susceptibility measurements were conducted on magnetically diluted and nondiluted samples of 1, indicating this compound to be an SMM with improved properties compared to those of the well-known [TbPc]+ and the axially symmetric dinuclear Tb phthalocyaninato triple-decker complex (Tb(obPc)). Assuming that the probability of quantum tunneling of the magnetization (QTM) occurring in one TbPc unit is Pqt, the probability of QTM simultaneously occurring in 1 is Pqt, meaning that QTM is effectively suppressed. Furthermore, nondiluted samples of 1 underwent slow magnetic relaxation times (τ " 1000 s at 0.1 K), and the blocking temperature (T) was determined to be ca. 16 K with an energy barrier for spin reversal (Uf of 588 cm (847 K) due to D geometry and weak inter-and intramolecular magnetic interactions as an exchange bias (Hb), reducing QTM. Four hyperfine steps were observed by micro-SQUID measurement. Furthermore, solution NMR measurements (one-dimensional, two-dimensional, and dynamic) were done on 1, which led to the determination of the high rotation barrier (83 ± 10 kJ/mol) of the obPc ligand. A comparison with previously reported Tb triple-decker compounds shows that ambient temperature NMR measurements can indicate improvements in the design of coordination environments for SMMs. A large Ucauses strong uniaxial magnetic anisotropy in 1, leading to a χvalue (1.39×10 m[sup 3]) that is larger than that for Tb2(obPc)3 (0.86×10 m[sup 3]). Controlling the coordination environment and spin arrangement is an effective technique for suppressing QTM in TbPc-based SMMs. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2018 holdings: @attributes: islocal: N |
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