Abstract
Single-molecule magnets that contain one spin centre may represent the smallest possible unit for spin-based computational devices. Such applications, however, require the realization of molecules with a substantial energy barrier for spin inversion, achieved through a large axial magnetic anisotropy. Recently, significant progress has been made in this regard by using lanthanide centres such as terbium(III) and dysprosium(III), whose anisotropy can lead to extremely high relaxation barriers. We contend that similar effects should be achievable with transition metals by maintaining a low coordination number to restrict the magnitude of the d-orbital ligand-field splitting energy (which tends to hinder the development of large anisotropies). Herein we report the first two-coordinate complex of iron(I), [Fe(C(SiMe3)3)2]−, for which alternating current magnetic susceptibility measurements reveal slow magnetic relaxation below 29 K in a zero applied direct-current field. This S = complex exhibits an effective spin-reversal barrier of Ueff = 226(4) cm−1, the largest yet observed for a single-molecule magnet based on a transition metal, and displays magnetic blocking below 4.5 K.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 12 print issues and online access
$259.00 per year
only $21.58 per issue
Rent or buy this article
Prices vary by article type
from$1.95
to$39.95
Prices may be subject to local taxes which are calculated during checkout





References
Ishikawa, N., Sugita, M., Ishikawa, T., Koshihara, S-Y. & Kaizu, Y. Lanthanide double-decker complexes functioning as magnets at the single-molecular level. J. Am. Chem. Soc. 125, 8694–8695 (2003).
Rinehart, J. D. & Long, J. R. Exploiting single-ion anisotropy in the design of f-element single-molecule magnets. Chem. Sci. 2, 2078–2085 (2011).
Gatteschi, D., Sessoli, R. & Villain, J. Molecular Nanomagnets (Oxford Univ. Press, 2006).
Branzoli, F. et al. Spin dynamics in the negatively charge terbium(III) bis-phthalocyaninato complex. J. Am. Chem. Soc. 131, 4387–4396 (2009).
Jiang, S-D., Wang, B-W., Sun, H-L., Wang, Z-M. & Gao, S. An organometallic single-ion magnet. J. Am. Chem. Soc. 133, 4730–4733 (2011).
Gonidec, M. et al. Surface supramolecular organization of a terbium(III) double-decker complex on graphite and its single molecule magnet behavior. J. Am. Chem. Soc. 133, 6603–6612 (2011).
Sessoli, R. et al. High-spin molecules: [Mn12O12(O2CR)16(H2O)4]. J. Am. Chem. Soc. 115, 1804–1816 (1993).
Sessoli, R., Gatteschi, D., Caneschi, A. & Novak, M. A. Magnetic bistability in a metal–ion cluster. Nature 365, 141–143 (1993).
Milios, C. J. et al. A record anisotropy barrier for a single-molecule magnet. J. Am. Chem. Soc. 129, 2754–2755 (2007).
Yoshihara, D., Karasawa, S. & Koga, N. Cyclic single-molecule magnet in heterospin system. J. Am. Chem. Soc. 130, 10460–10461 (2008).
Mannini, M. et al. Magnetic memory of a single-molecule quantum magnet wired to a gold surface. Nature Mater. 8, 194–197 (2009).
Leuenberger, M. N. & Loss, D. Quantum computing in molecular magnets. Nature 410, 789–793 (2001).
Ardavan, A. et al. Will spin-relaxation times in molecular magnets permit quantum information processing? Phys. Rev. Lett. 98, 057201-1–057201-4 (2007).
Stamp, P. C. E. & Gaita-Ariño, A. Spin-based quantum computers made by chemistry: hows and whys. J. Mater. Chem. 19, 1718–1730 (2009).
Bogani, L. & Wernsdorfer, W. Molecular spintronics using single-molecule magnets. Nature Mater. 7, 179–186 (2008).
Atanasov, M. et al. Detailed ab initio first-principles study of the magnetic anisotropy in a family of trigonal pyramidal iron(II) pyrrolide complexes. Inorg. Chem. 50, 7460–7477 (2011).
Freedman, D. E. et al. Slow magnetic relaxation in a high-spin iron(II) complex. J. Am. Chem. Soc. 132, 1224–1225 (2010).
Harman, W. H. et al. Slow magnetic relaxation in a family of trigonal pyramidal iron(II) pyrrolide complexes. J. Am. Chem. Soc. 132, 18115–18126 (2010).
Weismann, D. et al. High-spin cyclopentadienyl complexes: a single-molecule magnet based on the aryl–iron(II) cyclopentadienyl type. Chem. Eur. J. 17, 4700–4704 (2011).
Lin, P-H. et al. Importance of out-of-state spin–orbit coupling for slow magnetic relaxation in mononuclear FeII complexes. J. Am. Chem. Soc. 133, 15806–15809 (2011).
Jurca, T. et al. Single-molecule magnet behavior with a single metal center enhanced through peripheral ligand modifications. J. Am. Chem. Soc. 133, 15814–15817 (2011).
Vallejo, J. et al. Field-induced slow magnetic relaxation in a six-coordinate mononuclear cobalt(II) complex with a positive anisotropy. J. Am. Chem. Soc. 134, 15704–15707 (2012).
Kramers, H. A. A general theory of paramagnetic rotation in crystals. Proc. R. Acad. Sci. Amsterdam 33, 959–972 (1930).
Zadrozny, J. M. & Long, J. R. Slow magnetic relaxation at zero field in the tetrahedral complex [Co(SPh)4]2−. J. Am. Chem. Soc. 133, 20732–20734 (2011).
Mossin, S. et al. A mononuclear Fe(III) single molecule magnet with a 3/2↔5/2 spin crossover. J. Am. Chem. Soc. 134, 13651–13661 (2012).
Power, P. P. Stable two-coordinate, open-shell (d1–d9) transition metal complexes. Chem. Rev. 112, 3482–3507 (2012).
Reiff, W. M., LaPointe, A. M. & Witten, E. H. Virtual free ion magnetism and the absence of Jahn–Teller distortion in a linear two-coordinate complex of high-spin iron(II). J. Am. Chem. Soc. 126, 10206–10207 (2004).
Reiff, W. M. et al. Consequences of a linear two-coordinate geometry for the orbital magnetism and Jahn–Teller distortion behavior of the high spin iron(II) complex Fe[N(t-Bu)2]2 . J. Am. Chem. Soc. 131, 404–405 (2009).
Merrill, W. A. et al. Direct spectroscopic observation of large quenching of first-order orbital angular momentum with bending in monomeric, two-coordinate Fe(II) primary amido complexes and the profound magnetic effects of the absence of Jahn– and Renner–Teller distortions in rigorously linear coordination. J. Am. Chem. Soc. 131, 12695–12702 (2009).
Zadrozny, J. M. et al. Slow magnetization dynamics in a series of two-coordinate iron(II) complexes. Chem. Sci. 4, 125–138 (2013).
Atanasov, M. A., Zadrozny, J. M., Long, J. R. & Neese, F. A theoretical analysis of chemical bonding, vibronic coupling, and magnetic anisotropy in linear iron(II) complexes with single-molecule magnet behavior. Chem. Sci. 4, 139–156 (2013).
Eaborn, C., Hitchcock, P. B., Smith, J. D. & Sullivan, A. C. Crystal structure of the tetrahydrofuran adduct of tris(trimethylsilyl)-methyl-lithium, [Li(thf)4[Li{C(SiMe3)3}2]. J. Chem. Soc. Chem. Commun. 827–828 (1983).
Eaborn, C., Hitchcock, P. B., Smith, J. D. & Sullivan, A. C. Preparation and crystal structure of the tetrahydrofuran adduct of lithium bis[tris(trimethylsilyl)methyl]cuprate, [Li(THF)4][Cu{C(SiMe3)3}2]. The first structural characterization of a Gilman reagent. J. Organomet. Chem. 263, C23–C25 (1984).
Eaborn, C., Hitchcock, P. B., Smith, J. D. & Sullivan, A. C. Preparation and crystal structure of the argentate complex [Li(tetrahydrofuran)4][Ag{C{SiMe3)3}2]. J. Chem. Soc. Chem. Commun. 870–871 (1984).
Al-Juaid, S. S. et al. Metalation of tris(trimethylsilyl)- and tris(dimethylphenylsilyl)methane with methylsodium: the first dialkylsodate. Angew. Chem. Int. Ed. Engl. 33, 1268–1270 (1994).
LaPointe, A. M. Fe[C(SiMe3)3]2: synthesis and reactivity of a monomeric homoleptic iron(II) alkyl complex. Inorg. Chim. Acta 345, 359–362 (2003).
Stoian, S. A. et al. Mössbauer, electron paramagnetic resonance, and crystallographic characterization of a high-spin Fe(I) diketiminate complex with orbital degeneracy. Inorg. Chem. 44, 4915–4922 (2005).
Yu, Y. et al. The reactivity patterns of low-coordinate iron–hydride complexes. J. Am. Chem. Soc. 130, 6624–6638 (2008).
Nakajima, Y. et al. Electronic structure of four-coordinate iron(I) complex supported by a bis(phosphaethenyl)pyridine ligand. J. Am. Chem. Soc. 132, 9934–9936 (2010).
Carlin, R. Magnetochemistry (Springer, 1986).
Gatteschi, D. & Sessoli, R. Quantum tunneling of magnetization and related phenomena in molecular materials. Angew. Chem. Int. Ed. 42, 268–297 (2003).
Luis, F. et al. Spin–lattice relaxation via quantum tunneling in an Er3+-polyoxometalate molecular magnet. Phys. Rev. B. 82, 060403(R) (2010).
Meihaus, K. R., Rinehart, J. D. & Long, J. R. Dilution-induced slow magnetic relaxation and anomalous hysteresis in trigonal prismatic dysprosium(III) and uranium(III) complexes. Inorg. Chem. 50, 8484–8489 (2011).
Rinehart, J. D. & Long, J. R. Slow magnetic relaxation in homoleptic trispyrazolylborate complexes of neodymium(III) and uranium(III). Dalton Trans. 41, 13572–13574 (2012).
Rinehart, J. D., Fang, M., Evans, W. & Long, J. R. Strong exchange and magnetic blocking in N23− radical-bridged lanthanide complexes. Nature Chem. 3, 538–542 (2011).
Demir, S., Zadrozny, J. M., Nippe, M. & Long, J. R. Exchange coupling and magnetic blocking in bipyrimidyl radical-bridged dilanthanide complexes. J. Am. Chem. Soc. 134, 18546–18549 (2012).
Cole, K. S. & Cole, R. H. Dispersion and absorption in dielectrics. I. Alternating current characteristics. J. Chem. Phys. 9, 341–351 (1941).
Acknowledgements
This research was funded by the National Science Foundation through grant CHE-1010002. We thank R. Nichiporuk for assistance with ESI/MS acquisition, T. Chantarojsiri, M. Nippe and S. Demir for experimental assistance and M. Fasulo for valuable discussions.
Author information
Authors and Affiliations
Contributions
J.M.Z., D.J.X. and J.R.L. planned and executed the synthesis, characterization and magnetic measurements, and analysed the resulting data. M.A. and F.N. performed calculations and analysed the resulting data. G.J.L. and F.G. analysed the Mössbauer spectra. All authors were involved in writing the manuscript.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Supplementary information
Supplementary information
Supplementary information (PDF 4503 kb)
Supplementary information
Crystallographic data for compound 1 (CIF 46 kb)
Rights and permissions
About this article
Cite this article
Zadrozny, J., Xiao, D., Atanasov, M. et al. Magnetic blocking in a linear iron(I) complex. Nature Chem 5, 577–581 (2013). https://doi.org/10.1038/nchem.1630
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nchem.1630
This article is cited by
-
On the interpretation of Mössbauer isomer shifts of iron-organic compounds
Journal of Radioanalytical and Nuclear Chemistry (2023)
-
Computational design of magnetic molecules and their environment using quantum chemistry, machine learning and multiscale simulations
Nature Reviews Chemistry (2022)
-
On the correlation of the 57Fe Mӧssbauer isomer shift and some structural parameters of a substance
Hyperfine Interactions (2022)
-
Advanced Magnetic Resonance Studies of Tetraphenylporphyrinatoiron(III) Halides
Applied Magnetic Resonance (2020)