Cyanide single-molecule magnets exhibiting solvent dependent reversible "on" and "off" exchange bias behavior

Dawid Pinkowicz; Heather I. Southerland; Carolina Avendaño; Andrey Prosvirin; Codi Sanders; Wolfgang Wernsdorfer; Kasper Steen Pedersen; Jan Dreiser; Rodolphe Clérac; Joscha Nehrkorn; Giovanna G. Simeoni; Alexander Schnegg; Karsten Holldack; Kim R. Dunbar

doi:10.1021/jacs.5b09378

Cyanide single-molecule magnets exhibiting solvent dependent reversible "on" and "off" exchange bias behavior

Dawid Pinkowicz, Heather I. Southerland, Carolina Avendaño, Andrey Prosvirin, Codi Sanders, Wolfgang Wernsdorfer, Kasper Steen Pedersen, Jan Dreiser, Rodolphe Clérac, Joscha Nehrkorn, Giovanna G. Simeoni, Alexander Schnegg, Karsten Holldack, Kim R. Dunbar

Department of Chemistry

97 Citations (Scopus)

Abstract

The syntheses, structures, and magnetic properties of four new complex salts, (PPN){[Mn(III)(salphen)(MeOH)]2[M(III)(CN)6]}·7MeOH (Mn2M·7MeOH) (M = Fe, Ru, Os and Co; PPN(+) = bis(triphenylphosphoranylidene)ammonium cation; H2salphen = N,N'-bis(salicylidene)-1,2-diaminobenzene), and a mixed metal Co/Os analogue (PPN){[Mn(III)(salphen)(MeOH)]2[Co(III)0.92Os(III)0.08(CN)6]}·7MeOH were undertaken. It was found that all compounds exhibit switchable single-molecule magnet (SMM) and exchange-bias behavior depending on the interstitial methanol content. The pristine (PPN){[Mn(salphen)(MeOH)]2[Os(CN)6]}·7MeOH (Mn2Os·7MeOH) behaves as an SMM with an effective barrier for the magnetization reversal, (Ueff/kB), of 17.1 K. Upon desolvation, Mn2Os exhibits an increase of Ueff/kB to 42.0 K and an opening of the hysteresis loop observable at 1.8 K. Mn2Os·7MeOH shows also exchange-bias behavior with magnetic hysteresis loops exhibiting a shift in the quantum tunneling to 0.25 T from zero-field. The Fe(III) and Ru(III) analogues were prepared as reference compounds for assessing the effect of the 5d versus 4d and 3d metal ions on the SMM properties. These compounds are also SMMs and exhibit similar effects but with lower energy barriers. These findings underscore the importance of introducing heavy transition elements into SMMs to improve their slow relaxation of the magnetization properties. The (PPN){[Mn(III)(salphen)(MeOH)]2[Co(III)(CN)6]}·7MeOH (Mn2Co·7MeOH) analogue with a diamagnetic Co(III) central atom and the mixed Co/Os (PPN){[Mn(III)(salphen)(MeOH)]2[Co(III)0.92Os(III)0.08(CN)6]}·7MeOH (Mn2Co/Os·7MeOH) "magnetically diluted" system with a 9:1 Co/Os metal ratio were prepared in order to further probe the nature of the energy barrier increase upon desolvation of Mn2Os. In addition, inelastic neutron scattering and frequency-domain Fourier-transform THz electron paramagnetic resonance spectra obtained on Mn2Os·7MeOH and Mn2Os in combination with the magnetic data revealed the presence of anisotropic exchange interactions between Mn(III) and Os(III) ions.

Original language	English
Journal	Journal of the American Chemical Society
Volume	137
Issue number	45
Pages (from-to)	14406-14422
Number of pages	17
ISSN	0002-7863
DOIs	https://doi.org/10.1021/jacs.5b09378
Publication status	Published - 6 Nov 2015

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Pinkowicz, D., Southerland, H. I., Avendaño, C., Prosvirin, A., Sanders, C., Wernsdorfer, W., Pedersen, K. S., Dreiser, J., Clérac, R., Nehrkorn, J., Simeoni, G. G., Schnegg, A., Holldack, K., & Dunbar, K. R. (2015). Cyanide single-molecule magnets exhibiting solvent dependent reversible "on" and "off" exchange bias behavior. Journal of the American Chemical Society, 137(45), 14406-14422. https://doi.org/10.1021/jacs.5b09378

Pinkowicz, D, Southerland, HI, Avendaño, C, Prosvirin, A, Sanders, C, Wernsdorfer, W, Pedersen, KS, Dreiser, J, Clérac, R, Nehrkorn, J, Simeoni, GG, Schnegg, A, Holldack, K & Dunbar, KR 2015, 'Cyanide single-molecule magnets exhibiting solvent dependent reversible "on" and "off" exchange bias behavior', Journal of the American Chemical Society, vol. 137, no. 45, pp. 14406-14422. https://doi.org/10.1021/jacs.5b09378

@article{00f78802c1a44ca3a9ff1f8f3afc068e,

title = "Cyanide single-molecule magnets exhibiting solvent dependent reversible {"}on{"} and {"}off{"} exchange bias behavior",

abstract = "The syntheses, structures, and magnetic properties of four new complex salts, (PPN){[Mn(III)(salphen)(MeOH)]2[M(III)(CN)6]}·7MeOH (Mn2M·7MeOH) (M = Fe, Ru, Os and Co; PPN(+) = bis(triphenylphosphoranylidene)ammonium cation; H2salphen = N,N'-bis(salicylidene)-1,2-diaminobenzene), and a mixed metal Co/Os analogue (PPN){[Mn(III)(salphen)(MeOH)]2[Co(III)0.92Os(III)0.08(CN)6]}·7MeOH were undertaken. It was found that all compounds exhibit switchable single-molecule magnet (SMM) and exchange-bias behavior depending on the interstitial methanol content. The pristine (PPN){[Mn(salphen)(MeOH)]2[Os(CN)6]}·7MeOH (Mn2Os·7MeOH) behaves as an SMM with an effective barrier for the magnetization reversal, (Ueff/kB), of 17.1 K. Upon desolvation, Mn2Os exhibits an increase of Ueff/kB to 42.0 K and an opening of the hysteresis loop observable at 1.8 K. Mn2Os·7MeOH shows also exchange-bias behavior with magnetic hysteresis loops exhibiting a shift in the quantum tunneling to 0.25 T from zero-field. The Fe(III) and Ru(III) analogues were prepared as reference compounds for assessing the effect of the 5d versus 4d and 3d metal ions on the SMM properties. These compounds are also SMMs and exhibit similar effects but with lower energy barriers. These findings underscore the importance of introducing heavy transition elements into SMMs to improve their slow relaxation of the magnetization properties. The (PPN){[Mn(III)(salphen)(MeOH)]2[Co(III)(CN)6]}·7MeOH (Mn2Co·7MeOH) analogue with a diamagnetic Co(III) central atom and the mixed Co/Os (PPN){[Mn(III)(salphen)(MeOH)]2[Co(III)0.92Os(III)0.08(CN)6]}·7MeOH (Mn2Co/Os·7MeOH) {"}magnetically diluted{"} system with a 9:1 Co/Os metal ratio were prepared in order to further probe the nature of the energy barrier increase upon desolvation of Mn2Os. In addition, inelastic neutron scattering and frequency-domain Fourier-transform THz electron paramagnetic resonance spectra obtained on Mn2Os·7MeOH and Mn2Os in combination with the magnetic data revealed the presence of anisotropic exchange interactions between Mn(III) and Os(III) ions.",

author = "Dawid Pinkowicz and Southerland, {Heather I.} and Carolina Avenda{\~n}o and Andrey Prosvirin and Codi Sanders and Wolfgang Wernsdorfer and Pedersen, {Kasper Steen} and Jan Dreiser and Rodolphe Cl{\'e}rac and Joscha Nehrkorn and Simeoni, {Giovanna G.} and Alexander Schnegg and Karsten Holldack and Dunbar, {Kim R.}",

year = "2015",

month = nov,

day = "6",

doi = "10.1021/jacs.5b09378",

language = "English",

volume = "137",

pages = "14406--14422",

journal = "Journal of the American Chemical Society",

issn = "0002-7863",

publisher = "ACS Publications",

number = "45",

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TY - JOUR

T1 - Cyanide single-molecule magnets exhibiting solvent dependent reversible "on" and "off" exchange bias behavior

AU - Pinkowicz, Dawid

AU - Southerland, Heather I.

AU - Avendaño, Carolina

AU - Prosvirin, Andrey

AU - Sanders, Codi

AU - Wernsdorfer, Wolfgang

AU - Pedersen, Kasper Steen

AU - Dreiser, Jan

AU - Clérac, Rodolphe

AU - Nehrkorn, Joscha

AU - Simeoni, Giovanna G.

AU - Schnegg, Alexander

AU - Holldack, Karsten

AU - Dunbar, Kim R.

PY - 2015/11/6

Y1 - 2015/11/6

N2 - The syntheses, structures, and magnetic properties of four new complex salts, (PPN){[Mn(III)(salphen)(MeOH)]2[M(III)(CN)6]}·7MeOH (Mn2M·7MeOH) (M = Fe, Ru, Os and Co; PPN(+) = bis(triphenylphosphoranylidene)ammonium cation; H2salphen = N,N'-bis(salicylidene)-1,2-diaminobenzene), and a mixed metal Co/Os analogue (PPN){[Mn(III)(salphen)(MeOH)]2[Co(III)0.92Os(III)0.08(CN)6]}·7MeOH were undertaken. It was found that all compounds exhibit switchable single-molecule magnet (SMM) and exchange-bias behavior depending on the interstitial methanol content. The pristine (PPN){[Mn(salphen)(MeOH)]2[Os(CN)6]}·7MeOH (Mn2Os·7MeOH) behaves as an SMM with an effective barrier for the magnetization reversal, (Ueff/kB), of 17.1 K. Upon desolvation, Mn2Os exhibits an increase of Ueff/kB to 42.0 K and an opening of the hysteresis loop observable at 1.8 K. Mn2Os·7MeOH shows also exchange-bias behavior with magnetic hysteresis loops exhibiting a shift in the quantum tunneling to 0.25 T from zero-field. The Fe(III) and Ru(III) analogues were prepared as reference compounds for assessing the effect of the 5d versus 4d and 3d metal ions on the SMM properties. These compounds are also SMMs and exhibit similar effects but with lower energy barriers. These findings underscore the importance of introducing heavy transition elements into SMMs to improve their slow relaxation of the magnetization properties. The (PPN){[Mn(III)(salphen)(MeOH)]2[Co(III)(CN)6]}·7MeOH (Mn2Co·7MeOH) analogue with a diamagnetic Co(III) central atom and the mixed Co/Os (PPN){[Mn(III)(salphen)(MeOH)]2[Co(III)0.92Os(III)0.08(CN)6]}·7MeOH (Mn2Co/Os·7MeOH) "magnetically diluted" system with a 9:1 Co/Os metal ratio were prepared in order to further probe the nature of the energy barrier increase upon desolvation of Mn2Os. In addition, inelastic neutron scattering and frequency-domain Fourier-transform THz electron paramagnetic resonance spectra obtained on Mn2Os·7MeOH and Mn2Os in combination with the magnetic data revealed the presence of anisotropic exchange interactions between Mn(III) and Os(III) ions.

AB - The syntheses, structures, and magnetic properties of four new complex salts, (PPN){[Mn(III)(salphen)(MeOH)]2[M(III)(CN)6]}·7MeOH (Mn2M·7MeOH) (M = Fe, Ru, Os and Co; PPN(+) = bis(triphenylphosphoranylidene)ammonium cation; H2salphen = N,N'-bis(salicylidene)-1,2-diaminobenzene), and a mixed metal Co/Os analogue (PPN){[Mn(III)(salphen)(MeOH)]2[Co(III)0.92Os(III)0.08(CN)6]}·7MeOH were undertaken. It was found that all compounds exhibit switchable single-molecule magnet (SMM) and exchange-bias behavior depending on the interstitial methanol content. The pristine (PPN){[Mn(salphen)(MeOH)]2[Os(CN)6]}·7MeOH (Mn2Os·7MeOH) behaves as an SMM with an effective barrier for the magnetization reversal, (Ueff/kB), of 17.1 K. Upon desolvation, Mn2Os exhibits an increase of Ueff/kB to 42.0 K and an opening of the hysteresis loop observable at 1.8 K. Mn2Os·7MeOH shows also exchange-bias behavior with magnetic hysteresis loops exhibiting a shift in the quantum tunneling to 0.25 T from zero-field. The Fe(III) and Ru(III) analogues were prepared as reference compounds for assessing the effect of the 5d versus 4d and 3d metal ions on the SMM properties. These compounds are also SMMs and exhibit similar effects but with lower energy barriers. These findings underscore the importance of introducing heavy transition elements into SMMs to improve their slow relaxation of the magnetization properties. The (PPN){[Mn(III)(salphen)(MeOH)]2[Co(III)(CN)6]}·7MeOH (Mn2Co·7MeOH) analogue with a diamagnetic Co(III) central atom and the mixed Co/Os (PPN){[Mn(III)(salphen)(MeOH)]2[Co(III)0.92Os(III)0.08(CN)6]}·7MeOH (Mn2Co/Os·7MeOH) "magnetically diluted" system with a 9:1 Co/Os metal ratio were prepared in order to further probe the nature of the energy barrier increase upon desolvation of Mn2Os. In addition, inelastic neutron scattering and frequency-domain Fourier-transform THz electron paramagnetic resonance spectra obtained on Mn2Os·7MeOH and Mn2Os in combination with the magnetic data revealed the presence of anisotropic exchange interactions between Mn(III) and Os(III) ions.

U2 - 10.1021/jacs.5b09378

DO - 10.1021/jacs.5b09378

M3 - Journal article

C2 - 26542645

SN - 0002-7863

VL - 137

SP - 14406

EP - 14422

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

IS - 45

ER -

Cyanide single-molecule magnets exhibiting solvent dependent reversible "on" and "off" exchange bias behavior

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