Fluoride-bridged {Ln2Cr2} polynuclear complexes from semi-labile mer-[CrF3(py)3] and [Ln(hfac)3(H2O)2]

Christian Aa Thuesen; Kasper Steen Pedersen; Magnus Schau-Magnussen; Marco Evangelisti; Johan Vibenholt; Stergios Piligkos; Høgni Weihe; Jesper Bendix

doi:10.1039/c2dt31302b

Fluoride-bridged {Ln₂Cr₂} polynuclear complexes from semi-labile mer-[CrF₃(py)₃] and [Ln(hfac)₃(H₂O)₂]

Christian Aa Thuesen, Kasper Steen Pedersen, Magnus Schau-Magnussen, Marco Evangelisti, Johan Vibenholt, Stergios Piligkos, Høgni Weihe, Jesper Bendix

Research output: Contribution to journal › Journal article › Research › peer-review

Abstract

The trifluorido complex mer-[CrF₃(py)₃] (py = pyridine) reacts with 1 equiv. of [Ln(hfac)₃(H₂O)₂] and depending on the solvent forms the tetranuclear clusters [Cr₂Ln₂(μ-F)₄(μ-OH)₂(py)₄(hfac)₆], 1Ln, and [Cr₂Ln₂(μ-F)₄F₂(py)₆(hfac)₆], 2Ln, in acetonitrile and 1,2-dichloroethane, respectively (Ln = Y, Gd, Tb, Dy, Ho, and Er; hfacH = 1,1,1,5,5,5-hexafluoroacetylacetone). Reaction with [Dy(hfac)₃(H₂O)₂] in dichloromethane produces the dinuclear cluster [CrDy(μ-F)F(OH₂)(py)₃(hfac)₄], 3Dy. All the clusters feature fluoride bridges between the chromium(III) and lanthanide(III) centres. Fits of susceptibility data for 1Gd and 2Gd reveal the fluoride-mediated chromium(III)-lanthanide(III) exchange interactions to be 0.43(5) cm^-1 and 0.57(7) cm^-1, respectively (in the (H) over cap = J (S) over cap (1)•(S) over cap (2) convention). Heat capacity measurements on 2Gd reveal a moderate magneto-caloric effect (MCE) reaching -ΔS_m(T) = 11.4 J kg^-1K^-1 for ΔB₀ = 9 T -> 0 T at T = 4.1 K. Out-of-phase alternating-current susceptibility (chi '') signals are observed for 1Dy, 2Dy and 2Tb, demonstrating slow relaxation of the magnetization.

Original language	English
Journal	Dalton Transactions
Volume	41
Issue number	37
Pages (from-to)	11284-11292
ISSN	1477-9226
DOIs	https://doi.org/10.1039/c2dt31302b
Publication status	Published - 2012
Externally published	Yes

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@article{c81443ff060249c68be26f858c2f6ed8,

title = "Fluoride-bridged {Ln2Cr2} polynuclear complexes from semi-labile mer-[CrF3(py)3] and [Ln(hfac)3(H2O)2]",

abstract = "The trifluorido complex mer-[CrF3(py)3] (py = pyridine) reacts with 1 equiv. of [Ln(hfac)3(H2O)2] and depending on the solvent forms the tetranuclear clusters [Cr2Ln2(μ-F)4(μ-OH)2(py)4(hfac)6], 1Ln, and [Cr2Ln2(μ-F)4F2(py)6(hfac)6], 2Ln, in acetonitrile and 1,2-dichloroethane, respectively (Ln = Y, Gd, Tb, Dy, Ho, and Er; hfacH = 1,1,1,5,5,5-hexafluoroacetylacetone). Reaction with [Dy(hfac)3(H2O)2] in dichloromethane produces the dinuclear cluster [CrDy(μ-F)F(OH2)(py)3(hfac)4], 3Dy. All the clusters feature fluoride bridges between the chromium(III) and lanthanide(III) centres. Fits of susceptibility data for 1Gd and 2Gd reveal the fluoride-mediated chromium(III)-lanthanide(III) exchange interactions to be 0.43(5) cm-1 and 0.57(7) cm-1, respectively (in the (H) over cap = J (S) over cap (1)•(S) over cap (2) convention). Heat capacity measurements on 2Gd reveal a moderate magneto-caloric effect (MCE) reaching -ΔSm(T) = 11.4 J kg-1K-1 for ΔB0 = 9 T -> 0 T at T = 4.1 K. Out-of-phase alternating-current susceptibility (chi '') signals are observed for 1Dy, 2Dy and 2Tb, demonstrating slow relaxation of the magnetization.",

author = "Thuesen, {Christian Aa} and Pedersen, {Kasper Steen} and Magnus Schau-Magnussen and Marco Evangelisti and Johan Vibenholt and Stergios Piligkos and H{\o}gni Weihe and Jesper Bendix",

year = "2012",

doi = "10.1039/c2dt31302b",

language = "English",

volume = "41",

pages = "11284--11292",

journal = "Dalton Transactions",

issn = "1477-9226",

publisher = "Royal Society of Chemistry",

number = "37",

}

TY - JOUR

T1 - Fluoride-bridged {Ln2Cr2} polynuclear complexes from semi-labile mer-[CrF3(py)3] and [Ln(hfac)3(H2O)2]

AU - Thuesen, Christian Aa

AU - Pedersen, Kasper Steen

AU - Schau-Magnussen, Magnus

AU - Evangelisti, Marco

AU - Vibenholt, Johan

AU - Piligkos, Stergios

AU - Weihe, Høgni

AU - Bendix, Jesper

PY - 2012

Y1 - 2012

N2 - The trifluorido complex mer-[CrF3(py)3] (py = pyridine) reacts with 1 equiv. of [Ln(hfac)3(H2O)2] and depending on the solvent forms the tetranuclear clusters [Cr2Ln2(μ-F)4(μ-OH)2(py)4(hfac)6], 1Ln, and [Cr2Ln2(μ-F)4F2(py)6(hfac)6], 2Ln, in acetonitrile and 1,2-dichloroethane, respectively (Ln = Y, Gd, Tb, Dy, Ho, and Er; hfacH = 1,1,1,5,5,5-hexafluoroacetylacetone). Reaction with [Dy(hfac)3(H2O)2] in dichloromethane produces the dinuclear cluster [CrDy(μ-F)F(OH2)(py)3(hfac)4], 3Dy. All the clusters feature fluoride bridges between the chromium(III) and lanthanide(III) centres. Fits of susceptibility data for 1Gd and 2Gd reveal the fluoride-mediated chromium(III)-lanthanide(III) exchange interactions to be 0.43(5) cm-1 and 0.57(7) cm-1, respectively (in the (H) over cap = J (S) over cap (1)•(S) over cap (2) convention). Heat capacity measurements on 2Gd reveal a moderate magneto-caloric effect (MCE) reaching -ΔSm(T) = 11.4 J kg-1K-1 for ΔB0 = 9 T -> 0 T at T = 4.1 K. Out-of-phase alternating-current susceptibility (chi '') signals are observed for 1Dy, 2Dy and 2Tb, demonstrating slow relaxation of the magnetization.

AB - The trifluorido complex mer-[CrF3(py)3] (py = pyridine) reacts with 1 equiv. of [Ln(hfac)3(H2O)2] and depending on the solvent forms the tetranuclear clusters [Cr2Ln2(μ-F)4(μ-OH)2(py)4(hfac)6], 1Ln, and [Cr2Ln2(μ-F)4F2(py)6(hfac)6], 2Ln, in acetonitrile and 1,2-dichloroethane, respectively (Ln = Y, Gd, Tb, Dy, Ho, and Er; hfacH = 1,1,1,5,5,5-hexafluoroacetylacetone). Reaction with [Dy(hfac)3(H2O)2] in dichloromethane produces the dinuclear cluster [CrDy(μ-F)F(OH2)(py)3(hfac)4], 3Dy. All the clusters feature fluoride bridges between the chromium(III) and lanthanide(III) centres. Fits of susceptibility data for 1Gd and 2Gd reveal the fluoride-mediated chromium(III)-lanthanide(III) exchange interactions to be 0.43(5) cm-1 and 0.57(7) cm-1, respectively (in the (H) over cap = J (S) over cap (1)•(S) over cap (2) convention). Heat capacity measurements on 2Gd reveal a moderate magneto-caloric effect (MCE) reaching -ΔSm(T) = 11.4 J kg-1K-1 for ΔB0 = 9 T -> 0 T at T = 4.1 K. Out-of-phase alternating-current susceptibility (chi '') signals are observed for 1Dy, 2Dy and 2Tb, demonstrating slow relaxation of the magnetization.

U2 - 10.1039/c2dt31302b

DO - 10.1039/c2dt31302b

M3 - Journal article

SN - 1477-9226

VL - 41

SP - 11284

EP - 11292

JO - Dalton Transactions

JF - Dalton Transactions

IS - 37