Static and dynamic magnetic properties of the tetracoordinate CoII complex [Co(CH3-im)2Cl2], (1, CH3-im = N-methyl-imidazole), studied using thorough analyses of magnetometry, and High-Frequency and -Field EPR (HFEPR) measurements, are reported. The study was supported by ab initio complete active space self-consistent field (CASSCF) calculations. It has been revealed that 1 possesses a large magnetic anisotropy with a large rhombicity (magnetometry: D = -13.5 cm-1, E/D = 0.33; HFEPR: D = -14.5(1) cm-1, E/D = 0.16(1)). These experimental results agree well with the theoretical calculations (D = -11.2 cm-1, E/D = 0.18). Furthermore, it has been revealed that 1 behaves as a field-induced single-ion magnet with a relatively large spin-reversal barrier (Ueff = 33.5 K). The influence of the Cl-Co-Cl angle on magnetic anisotropy parameters was evaluated using the CASSCF calculations.

Institute of Physical Chemistry University of Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany

Regional Centre of Advanced Technologies and Materials Department of Inorganic Chemistry Faculty of Science Palacký University 17 listopadu 12 CZ 771 46 Olomouc Czech Republic

Zobrazit více v PubMed

Ganzhorn M., Wernsdorfer W. In: Molecular Magnets. Bartolome J., Luis F., Fernandez J.F., editors. Springer; Berlin Heidelberg, Germany: 2014. pp. 319–364.

Gómez-Coca S., Aravena D., Morales R., Ruiz E. Large magnetic anisotropy in mononuclear metal complexes. Coord. Chem Rev. 2015;289–290:379–392. doi: 10.1016/j.ccr.2015.01.021. DOI

Boča R. Zero-field splitting in metal complexes. Coord. Chem Rev. 2004;248:757–815. doi: 10.1016/j.ccr.2004.03.001. DOI

Atanasov M., Aravena D., Suturina E., Bill E., Maganas D., Neese F. First principles approach to the electronic structure, magnetic anisotropy and spin relaxation in mononuclear 3d-transition metal single molecule magnets. Coord. Chem Rev. 2015;289–290:177–214. doi: 10.1016/j.ccr.2014.10.015. DOI

Waldmann O. A criterion for the anisotropy barrier in single-molecule magnets. Inorg. Chem. 2007;46:10035–10037. doi: 10.1021/ic701365t. PubMed DOI

Neese F., Pantazis D.A. What is not required to make a single molecule magnet. Farad. Discuss. 2011;148:229–238; discussion 299–314. doi: 10.1039/C005256F. PubMed DOI

Herchel R., Nemec I., Machata M., Trávníček Z. Solvent-induced structural diversity in tetranuclear Ni(II) schiff-base complexes: The first Ni4 single-molecule magnet with a defective dicubane-like topology. Dalton Trans. 2016;45:18622–18634. doi: 10.1039/C6DT03520E. PubMed DOI

Jiang S.-D., Maganas D., Levesanos N., Ferentinos E., Haas S., Thirunavukkuarasu K., Krzystek J., Dressel M., Bogani L., Neese F., et al. Direct observation of very large zero-field splitting in a tetrahedral niiise4 coordination complex. J. Am. Chem. Soc. 2015;137:12923–12928. doi: 10.1021/jacs.5b06716. PubMed DOI

Titiš J., Miklovič J., Boča R. Magnetostructural study of tetracoordinate cobalt(II) complexes. Inorg. Chem. Comm. 2013;35:72–75. doi: 10.1016/j.inoche.2013.05.031. DOI

Nemec I., Herchel R., Svoboda I., Boca R., Trávníček Z. Large and negative magnetic anisotropy in pentacoordinate mononuclear Ni(II) Schiff base complexes. Dalton Trans. 2015;44:9551–9560. doi: 10.1039/C5DT00600G. PubMed DOI

Nemec I., Liu H., Herchel R., Zhang X., Trávníček Z. Magnetic anisotropy in pentacoordinate 2,6-bis(arylazanylidene-1-chloromethyl)pyridine cobalt(II) complexes with chlorido co-ligands. Synth. Met. 2016;215:158–163. doi: 10.1016/j.synthmet.2016.02.014. DOI

Titiš J., Boča R. Magnetostructural d correlation in nickel(II) complexes: Reinvestigation of the zero-field splitting. Inorg. Chem. 2010;49:3971–3973. doi: 10.1021/ic902569z. PubMed DOI

Titiš J., Boča R. Magnetostructural d correlations in hexacoordinated cobalt(II) complexes. Inorg. Chem. 2011;50:11838–11845. doi: 10.1021/ic202108j. PubMed DOI

Werncke C.G., Bouammali M.-A., Baumard J., Suaud N., Martins C., Guihéry N., Vendier L., Zheng J., Sortais J.-B., Darcel C., et al. Ising-type magnetic anisotropy and slow relaxation of the magnetization in four-coordinate amido-pyridine Fe(II) complexes. Inorg. Chem. 2016;55:10968–10977. doi: 10.1021/acs.inorgchem.6b01512. PubMed DOI

Nemec I., Herchel R., Trávníček Z. Pentacoordinate and hexacoordinate Mn(III) complexes of tetradentate schiff-base ligands containing tetracyanidoplatinate(II) bridges and revealing uniaxial magnetic anisotropy. Molecules. 2016;21:1681. doi: 10.3390/molecules21121681. PubMed DOI PMC

Maurice R., de Graaf C., Guihéry N. Magnetostructural relations from a combined ab initio and ligand field analysis for the nonintuitive zero-field splitting in Mn(III) complexes. J. Chem. Phys. 2010;133:084307. doi: 10.1063/1.3480014. PubMed DOI

Nemec I., Herchel R., Trávníček Z. Suppressing of slow magnetic relaxation in tetracoordinate Co(II) field-induced single-molecule magnet in hybrid material with ferromagnetic barium ferrite. Sci. Rep. 2015;5:10761. doi: 10.1038/srep10761. PubMed DOI PMC

Zadrozny J.M., Telser J., Long J.R. Slow magnetic relaxation in the tetrahedral cobalt(II) complexes [Co(EPh)4]2− (E=O, S, Se) Polyhedron. 2013;64:209–217. doi: 10.1016/j.poly.2013.04.008. DOI

Rechkemmer Y., Breitgoff F.D., van der Meer M., Atanasov M., Hakl M., Orlita M., Neugebauer P., Neese F., Sarkar B., van Slageren J. A four-coordinate cobalt(II) single-ion magnet with coercivity and a very high energy barrier. Nat. Commun. 2016;7:10467. doi: 10.1038/ncomms10467. PubMed DOI PMC

Fataftah M.S., Zadrozny J.M., Rogers D.M., Freedman D.E. A mononuclear transition metal single-molecule magnet in a nuclear spin-free ligand environment. Inorg. Chem. 2014;53:10716–10721. doi: 10.1021/ic501906z. PubMed DOI

Sottini S., Poneti G., Ciattini S., Levesanos N., Ferentinos E., Krzystek J., Sorace L., Kyritsis P. Magnetic anisotropy of tetrahedral coii single-ion magnets: Solid-state effects. Inorg. Chem. 2016;55:9537–9548. doi: 10.1021/acs.inorgchem.6b00508. PubMed DOI

Allen F.H. The Cambridge Structural Database: A quarter of a million crystal structures and rising. Acta Cryst. 2002;B58:380–388. doi: 10.1107/S0108768102003890. PubMed DOI

Smolko L., Černák J., Dušek M., Miklovič J., Titiš J., Boča R. Three tetracoordinate co(ii) complexes [Co(biq)X2] (X = Cl, Br, I) with easy-plane magnetic anisotropy as field-induced single-molecule magnets. Dalton Trans. 2015;44:17565–17571. doi: 10.1039/C5DT02827B. PubMed DOI

Mondal A.K., Parmar V.S., Biswas S., Konar S. Tetrahedral mii based binuclear double-stranded helicates: Single-ion-magnet and fluorescence behaviour. Dalton Trans. 2016;45:4548–4557. doi: 10.1039/C5DT04173B. PubMed DOI

Ziegenbalg S., Hornig D., Görls H., Plass W. Cobalt(ii)-based single-ion magnets with distorted pseudotetrahedral [n2o2] coordination: Experimental and theoretical investigations. Inorg. Chem. 2016;55:4047–4058. doi: 10.1021/acs.inorgchem.6b00373. PubMed DOI

Mukerjee S., Skogerson K., DeGala S., Caradonna J.P. Skirting the oxo-wall: Characterization and catalytic reactivity of binuclear Co2+/3+ 1,2-bis(2-hydroxybenzamido)benzene complexes with comparison to their isostructural Fe2+/3+ analogs. Implications of d-electron count on oxygen atom transfer catalysis. Inorg. Chim. Acta. 2000;297:313–329. doi: 10.1016/S0020-1693(99)00431-4. DOI

Boča R. Theoretical Foundations of Molecular Magnetism. Elsevier; Amsterdam, The Netherlands: 1999.

Neese F. The ORCA program system. Wiley Interdiscip. Rev.-Comput. Mol. Sci. 2012;2:73–78. doi: 10.1002/wcms.81. DOI

Antal P., Drahoš B., Herchel R., Trávníček Z. Late first-row transition-metal complexes containing a 2-pyridylmethyl pendant-armed 15-membered macrocyclic ligand. Field-induced slow magnetic relaxation in a seven-coordinate cobalt(II) compound. Inorg. Chem. 2016;55:5957–5972. doi: 10.1021/acs.inorgchem.6b00415. PubMed DOI

Yang F., Zhou Q., Zhang Y., Zeng G., Li G., Shi Z., Wang B., Feng S. Inspiration from old molecules: Field-induced slow magnetic relaxation in three air-stable tetrahedral cobalt(II) compounds. Chem. Commun. 2013;49:5289–5291. doi: 10.1039/c3cc00277b. PubMed DOI

Boča R., Miklovič J., Titiš J. Simple mononuclear cobalt(II) complex: A single-molecule magnet showing two slow relaxation processes. Inorg. Chem. 2014;53:2367–2369. doi: 10.1021/ic5000638. PubMed DOI

Saber M.R., Dunbar K.R. Ligands effects on the magnetic anisotropy of tetrahedral cobalt complexes. Chem. Commun. 2014;50:12266–12269. doi: 10.1039/C4CC05724D. PubMed DOI

Idešicová M., Titiš J., Krzystek J., Boča R. Zero-field splitting in pseudotetrahedral Co(II) complexes: A magnetic, high-frequency and -field epr, and computational study. Inorg. Chem. 2013;52:9409–9417. doi: 10.1021/ic400980b. PubMed DOI

Rajnák C., Packová A., Titiš J., Miklovič J., Moncol’ J., Boča R. A tetracoordinate Co(II) single molecule magnet based on triphenylphosphine and isothiocyanato group. Polyhedron. 2016;110:85–92. doi: 10.1016/j.poly.2016.02.026. DOI

Huang W., Liu T., Wu D., Cheng J., Ouyang Z.W., Duan C. Field-induced slow relaxation of magnetization in a tetrahedral Co(II) complex with easy plane anisotropy. Dalton Trans. 2013;42:15326–15331. doi: 10.1039/c3dt51801a. PubMed DOI

Smolko L., Cernak J., Dusek M., Titiš J., Boča R. Tetracoordinate Co(II) complexes containing bathocuproine and single molecule magnetism. New J. Chem. 2016;40:6593–6598. doi: 10.1039/C6NJ00372A. DOI

Maganas D., Milikisyants S., Rijnbeek J.M.A., Sottini S., Levesanos N., Kyritsis P., Groenen E.J.J. A multifrequency high-field electron paramagnetic resonance study of coiis4 coordination. Inorg. Chem. 2010;49:595–605. doi: 10.1021/ic901911h. PubMed DOI

Stoll S., Schweiger A. EasySpin, a comprehensive software package for spectral simulations and analysis in EPR. J. Magn. Reson. 2006;178:42–55. doi: 10.1016/j.jmr.2005.08.013. PubMed DOI

Pantazis D.A., Chen X.-Y., Landis C.R., Neese F. All-Electron Scalar Relativistic Basis Sets for Third-Row Transition Metal Atoms. J. Chem. Theory Comput. 2008;4:908–919. doi: 10.1021/ct800047t. PubMed DOI

van Lenthe E., Baerends E.J., Snijders J.G. Relativistic regular two-component Hamiltonians. J. Chem. Phys. 1993;99:4597–4610. doi: 10.1063/1.466059. DOI

Van Wüllen C. Molecular density functional calculations in the regular relativistic approximation: Method, application to coinage metal diatomics, hydrides, fluorides and chlorides, and comparison with first-order relativistic calculations. J. Chem. Phys. 1998;109:392–399. doi: 10.1063/1.476576. DOI

Malmqvist P.-Å., Roos B.O. The CASSCF state interaction method. Chem. Phys. Lett. 1989;155:189–194. doi: 10.1016/0009-2614(89)85347-3. DOI

Angeli C., Cimiraglia R., Evangelisti S., Leininger T., Malrieu J.P. Introduction of n-electron valence states for multireference perturbation theory. J. Chem. Phys. 2001;114:10252–10264. doi: 10.1063/1.1361246. DOI

Ganyushin D., Neese F. First-principles calculations of zero-field splitting parameters. J. Chem. Phys. 2006;125:024103. doi: 10.1063/1.2213976. PubMed DOI

Neese F. Efficient and accurate approximations to the molecular spin-orbit coupling operator and their use in molecular g-tensor calculations. J. Chem. Phys. 2005;122:034107. doi: 10.1063/1.1829047. PubMed DOI

Maurice R., Bastardis R., de Graaf C., Suaud N., Mallah T., Guihéry N. Universal Theoretical Approach to Extract Anisotropic Spin Hamiltonians. J. Chem. Theory Comput. 2009;5:2977–2984. doi: 10.1021/ct900326e. PubMed DOI

Perdew J.P., Burke K., Ernzerhof M. Generalized gradient approximation made simple. Phys. Rev. Lett. 1996;77:3865–3868. doi: 10.1103/PhysRevLett.77.3865. PubMed DOI

Grimme S., Antony J., Ehrlich S., Krieg H. A consistent and accurate ab initio parametrization of density functional dispersion correction (dft-d) for the 94 elements h-pu. J. Chem. Phys. 2010;132:154104. doi: 10.1063/1.3382344. PubMed DOI

Synthesis, structural and magnetic properties of cobalt(ii) complexes with pyridine-based macrocyclic ligand containing two pyridine pendant arms