Simple Method and Materials to Target Co(II)-Dy(III) Multi-Nuclear Magnetic Compounds and Single Molecule Magnets (SMMs): Synthesis, Structure, and Magnetic Studies

2013 ◽  
Vol 66 (1) ◽  
pp. 75 ◽  
Author(s):  
Yan Zhu ◽  
Feng Luo ◽  
Xue-Feng Feng ◽  
Zhen-Wei Liao ◽  
Yu-Mei Song ◽  
...  
Keyword(s):  
Single Molecule ◽  
Donor Ligands ◽  
X Ray Diffraction ◽  
Magnetic Studies ◽  
Single Molecule Magnets ◽  
Simple Method ◽  
Single Molecule Magnet ◽  
X Ray ◽  
Nitrobenzoic Acid ◽  
Slow Magnetic Relaxation

In this work, based on mixed N-, O-donor ligands, a series of Co(ii)-Dy(iii) compounds are synthesised and characterised by single crystal X-ray diffraction and magnetic studies. These compounds include Co2(phen)2Dy(PhCOO)7 (1), Co2(phen)2Dy2(PhCOO)10 (2), Co(bpy)Dy(H2O)(CH3-PhCOO)5 (3), Co(phen)Dy(H2O)(CH3-PhCOO)5 (4), Co2(phen)2Dy(NO2-PhCOO)7 (5), Co2(phen)2Dy2(NO2-PhCOO)10 (6), and Co2(bpy)2Dy2(NO2-PhCOO)10 (7), where phen, bpy, CH3-PhCOOH, and NO2-PhCOOH are 1,10-phenanthroline, 2,2′-bipyridine, 3-methylbenzoic acid, and 3-nitrobenzoic acid, respectively. In these cases, di-, tri-, and tetranuclear Co-Dy clusters are observed. Direct current (DC) magnetic susceptibility reveals ferromagnetic or antiferromagnetic behaviour, whilst dynamic magnetic studies disclose single molecule magnet (SMM)-like slow magnetic relaxation for most of these compounds.

Polyoxometalate-Supported Lanthanoid Single-Molecule Magnets

2014 ◽  
Vol 67 (11) ◽  
pp. 1542 ◽  
Author(s):  
Michele Vonci ◽  
Colette Boskovic
Keyword(s):  
Single Molecule ◽  
Energy Barrier ◽  
Magnetic Relaxation ◽  
Donor Ligands ◽  
Single Molecule Magnets ◽  
Single Molecule Magnet ◽  
Coordination Numbers ◽  
Oxygen Donor ◽  
Slow Magnetic Relaxation

Polyoxometalates are robust and versatile multidentate oxygen-donor ligands, eminently suitable for coordination to trivalent lanthanoid ions. To date, 10 very different structural families of such complexes have been found to exhibit slow magnetic relaxation due to single-molecule magnet (SMM) behaviour associated with the lanthanoid ions. These families encompass complexes with between one and four of the later lanthanoid ions: Tb, Dy, Ho, Er, and Yb. The lanthanoid coordination numbers vary between six and eleven and a range of coordination geometries are evident. The highest energy barrier to magnetisation reversal measured to date for a lanthanoid–polyoxometalate SMM is Ueff/kB = 73 K for the heterodinuclear Dy–Eu compound (Bu4N)8H4[DyEu(OH)2(γ-SiW10O36)2].

scholarly journals Dysprosium Single-Molecule Magnets Involving 1,10-Phenantroline-5,6-dione Ligand

2020 ◽  
Vol 6 (2) ◽  
pp. 19 ◽  
Author(s):  
Olivier Galangau ◽  
Jessica Flores Gonzalez ◽  
Vincent Montigaud ◽  
Vincent Dorcet ◽  
Boris le Guennic ◽  
...  
Keyword(s):  
Single Molecule ◽  
Quantum Tunneling ◽  
Magnetic Relaxation ◽  
Supramolecular Assembly ◽  
X Ray Diffraction ◽  
Single Molecule Magnets ◽  
Single Molecule Magnet ◽  
X Ray ◽  
Mononuclear Complexes ◽  
Coordination Reaction

The two mononuclear complexes of the formula [Dy(tta)3(L)] (1) and [Dy(hfac)3(L)] (2) (where tta- = 2-thenoytrifluoroacetylacetonate and hfac- = 1,1,1,5,5,5-hexafluoroacetylacetonate) were obtained from the coordination reaction of the Dy(tta)3·2H2O or Dy(hfac)3·2H2O units with the 1,10-phenantroline-5,6-dione ligand (L). Their structures have been determined by X-ray diffraction studies on single crystals, and they revealed a supramolecular assembly of tetramers through σ-π interactions. Both complexes displayed a Single-Molecule Magnet (SMM) behavior without an external applied magnetic field. Magnetic relaxation happened through Orbach, Raman and Quantum Tunneling of the Magnetization (QTM). Wavefunction theory calculations were realized to rationalize the magnetic properties.

Cobalt(II) chloride adducts with acetonitrile, propan-2-ol and tetrahydrofuran: considerations on nuclearity, reactivity and synthetic applications

2017 ◽  
Vol 73 (2) ◽  
pp. 104-114 ◽  
Author(s):  
Danilo Stinghen ◽  
André Luis Rüdiger ◽  
Siddhartha O. K. Giese ◽  
Giovana G. Nunes ◽  
Jaísa F. Soares ◽  
...  
Keyword(s):  
Single Molecule ◽  
Building Blocks ◽  
Direct Reaction ◽  
X Ray Diffraction ◽  
Single Molecule Magnets ◽  
X Ray ◽  
Ft Ir ◽  
Bond Network ◽  
Solvent Molecules ◽  
Intramolecular Hydrogen

High-spin cobalt(II) complexes are considered useful building blocks for the synthesis of single-molecule magnets (SMM) because of their intrinsic magnetic anisotropy. In this work, three new cobalt(II) chloride adducts with labile ligands have been synthesized from anhydrous CoCl2, to be subsequently employed as starting materials for heterobimetallic compounds. The products were characterized by elemental, spectroscopic (EPR and FT–IR) and single-crystal X-ray diffraction analyses.trans-Tetrakis(acetonitrile-κN)bis(tetrahydrofuran-κO)cobalt(II) bis[(acetonitrile-κN)trichloridocobaltate(II)], [Co(C2H3N)4(C4H8O)2][CoCl3(C2H3N)]2, (1), comprises mononuclear ions and contains both acetonitrile and tetrahydrofuran (thf) ligands, The coordination polymercatena-poly[[tetrakis(propan-2-ol-κO)cobalt(II)]-μ-chlorido-[dichloridocobalt(II)]-μ-chlorido], [Co2Cl4(C3H8O)4], (2′), was prepared by direct reaction between anhydrous CoCl2and propan-2-ol in an attempt to rationalize the formation of the CoCl2–alcohol adduct (2), probably CoCl2(HOiPr)m. The binuclear complex di-μ-chlorido-1:2κ4Cl:Cl-dichlorido-2κ2Cl-tetrakis(tetrahydrofuran-1κO)dicobalt(II), [Co2Cl4(C4H8O)4], (3), was obtained from (2) after recrystallization from tetrahydrofuran. All three products present cobalt(II) centres in both octahedral and tetrahedral environments, the former usually less distorted than the latter, regardless of the nature of the neutral ligand. Product (2′) is stabilized by an intramolecular hydrogen-bond network that appears to favour atransarrangement of the chloride ligands in the octahedral moiety; this differs from thecisdisposition found in (3). The expected easy displacement of the bound solvent molecules from the metal coordination sphere makes the three compounds good candidates for suitable starting materials in a number of synthetic applications.

Structures, fluorescence properties and magnetic properties of a series of rhombus-shaped LnIII4 clusters: magnetocaloric effect and single-molecule-magnet behavior

2019 ◽  
Vol 43 (33) ◽  
pp. 12941-12949 ◽  
Author(s):  
Wen-Min Wang ◽  
Li Zhang ◽  
Xian-Zhen Li ◽  
Li-Yuan He ◽  
Xin-Xin Wang ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetocaloric Effect ◽  
Single Molecule ◽  
Magnetic Relaxation ◽  
Magnetic Refrigeration ◽  
Fluorescence Properties ◽  
Relaxation Processes ◽  
Magnetic Studies ◽  
Single Molecule Magnet ◽  
Slow Magnetic Relaxation

A family LnIII4 clusters were successfully synthesized and structurally characterized. Magnetic studies show that Gd4 cluster displays magnetic refrigeration, while Dy4 cluster demonstrates two distinct slow magnetic relaxation processes.

Two CoII coordination polymers of biphenyl-2,2′,5,5′-tetracarboxylic acid with flexible N-donor ligands: syntheses, structures and magnetic properties

2019 ◽  
Vol 75 (8) ◽  
pp. 1073-1083 ◽  
Author(s):  
Feng Su ◽  
Cheng-Yong Zhou ◽  
Lin-Tao Wu ◽  
Xi Wu ◽  
Jing Su ◽  
...  
Keyword(s):  
Coordination Polymers ◽  
Three Dimensional ◽  
Donor Ligands ◽  
Tetracarboxylic Acid ◽  
X Ray Diffraction ◽  
Magnetic Studies ◽  
Orbital Contribution ◽  
X Ray ◽  
3D Network ◽  
Methyl Benzene

Two CoII-based coordination polymers, namely poly[(μ4-biphenyl-2,2′,5,5′-tetracarboxylato){μ2-1,3-bis[(1H-imidazol-1-yl)methyl]benzene}dicobalt(II)], [Co2(C16H6O8)(C14H14N4)2] n or [Co2(o,m-bpta)(1,3-bimb)2] n (I), and poly[[aqua(μ4-biphenyl-2,2′,5,5′-tetracarboxylato){1,4-bis[(1H-imidazol-1-yl)methyl]benzene}dicobalt(II)] dihydrate], {[Co2(C16H6O8)(C14H14N4)2(H2O)2]·4H2O} n or {[Co2(o,m-bpta)(1,4-bimb)2(H2O)2]·4H2O} n (II), were synthesized from a mixture of biphenyl-2,2′,5,5′-tetracarboxylic acid, i.e. [H4(o,m-bpta)], CoCl2·6H2O and N-donor ligands under solvothermal conditions. The complexes were characterized by IR spectroscopy, elemental analysis, single-crystal X-ray diffraction and powder X-ray diffraction analysis. The bridging (o,m-bpta)4− ligands combine with CoII ions in different μ4-coordination modes, leading to the formation of one-dimensional chains. The central CoII atoms display tetrahedral [CoN2O2] and octahedral [CoN2O4] geometries in I and II, respectively. The bis[(1H-imidazol-1-yl)methyl]benzene (bimb) ligands adopt trans or cis conformations to connect CoII ions, thus forming two three-dimensional (3D) networks. Complex I shows a (2,4)-connected 3D network with left- and right-handed helical chains constructed by (o,m-bpta)4− ligands. Complex II is a (4,4)-connected 3D novel network with ribbon-like chains formed by (o,m-bpta)4− linkers. Magnetic studies indicate an orbital contribution to the magnetic moment of I and II due to the longer Co...Co distances. An attempt has been made to fit the χM T results to the magnetic formulae for mononuclear CoII complexes, the fitting indicating the presence of weak antiferromagnetic interactions between the CoII ions.

scholarly journals Bis-cyclooctatetraenyl Thulium(II): Highly Reducing Lanthanide Sandwich Single Molecule Magnets

2020 ◽  
Author(s):  
Jules Moutet ◽  
jules Schleinitz ◽  
Leo La Droitte ◽  
Maxime Tricoire ◽  
Frédéric Gendron ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Single Molecule ◽  
Single Electron Transfer ◽  
Small Molecule Activation ◽  
Sandwich Complex ◽  
Magnetic Studies ◽  
Single Molecule Magnets ◽  
Single Molecule Magnet ◽  
Divalent Lanthanide ◽  
Reliable Basis

Divalent lanthanide organometallics are well known highly reducing compounds usually used for single electron transfer reactivity and small molecule activation. Thus, their very reactive nature prevented for many years the study of their physical properties, such as magnetic studies on a reliable basis. In this article, the access to rare organometallic sandwich compounds of Tm<sup>II</sup> with the cyclooctatetraenyl (Cot) ligand impacts on the use of divalent organolanthanide compounds as an additional strategy for the design of performing Single Molecule Magnets (SMM). Herein, the first divalent thulium sandwich complex with f<sup>13</sup> configuration behaving as a Single Molecule Magnet in absence of DC field is highlighted.

Determination of d-Orbital Populations in a Cobalt(II) Single-Molecule Magnet Using Single-Crystal X-ray Diffraction

2018 ◽  
Vol 57 (12) ◽  
pp. 6913-6920 ◽  
Author(s):  
Matthew Craven ◽  
Mathilde H. Nygaard ◽  
Joseph M. Zadrozny ◽  
Jeffrey R. Long ◽  
Jacob Overgaard
Keyword(s):  
Single Crystal ◽  
Single Molecule ◽  
X Ray Diffraction ◽  
Single Molecule Magnet ◽  
X Ray

Field-induced slow magnetic relaxation in mixed valence di- and tri-nuclear CoII–CoIII complexes

2020 ◽  
Vol 49 (27) ◽  
pp. 9516-9528 ◽  
Author(s):  
Aparup Paul ◽  
Marta Viciano-Chumillas ◽  
Horst Puschmann ◽  
Joan Cano ◽  
Subal Chandra Manna
Keyword(s):  
Low Temperature ◽  
Single Crystal ◽  
Magnetic Relaxation ◽  
Mixed Valence ◽  
X Ray Diffraction ◽  
Magnetic Studies ◽  
X Ray ◽  
Slow Magnetic Relaxation

Two novel mixed valence di/tri nuclear CoII–CoIII complexes were synthesized and characterized by single crystal X-ray diffraction. Magnetic studies at low temperature revealed that both complexes show slow magnetic relaxation.

scholarly journals Bis-cyclooctatetraenyl Thulium(II): Highly Reducing Lanthanide Sandwich Single Molecule Magnets

2020 ◽  
Author(s):  
Jules Moutet ◽  
jules Schleinitz ◽  
Leo La Droitte ◽  
Maxime Tricoire ◽  
Frédéric Gendron ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Single Molecule ◽  
Single Electron Transfer ◽  
Small Molecule Activation ◽  
Sandwich Complex ◽  
Magnetic Studies ◽  
Single Molecule Magnets ◽  
Single Molecule Magnet ◽  
Divalent Lanthanide ◽  
Reliable Basis

Divalent lanthanide organometallics are well known highly reducing compounds usually used for single electron transfer reactivity and small molecule activation. Thus, their very reactive nature prevented for many years the study of their physical properties, such as magnetic studies on a reliable basis. In this article, the access to rare organometallic sandwich compounds of Tm<sup>II</sup> with the cyclooctatetraenyl (Cot) ligand impacts on the use of divalent organolanthanide compounds as an additional strategy for the design of performing Single Molecule Magnets (SMM). Herein, the first divalent thulium sandwich complex with f<sup>13</sup> configuration behaving as a Single Molecule Magnet in absence of DC field is highlighted.

scholarly journals Series of Chloranilate-Bridged Dinuclear Lanthanide Complexes: Kramers Systems Showing Field-Induced Slow Magnetic Relaxation

2019 ◽  
Vol 5 (2) ◽  
pp. 30 ◽  
Author(s):  
Ryuta Ishikawa ◽  
Shoichi Michiwaki ◽  
Takeshi Noda ◽  
Keiichi Katoh ◽  
Masahiro Yamashita ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Single Molecule ◽  
Magnetic Relaxation ◽  
Lanthanide Complexes ◽  
Relaxation Processes ◽  
X Ray Diffraction ◽  
Single Molecule Magnets ◽  
Magnetic Susceptibility Data ◽  
Susceptibility Data ◽  
Slow Magnetic Relaxation

A series of chloralilate-bridged dinuclear lanthanide complexes of formula [{LnIII(Tp)2}2(μ-Cl2An)]·2CH2Cl2, where Cl2An2− and Tp− represent the chloranilate and hydrotris (pyrazolyl)borate ligands, respectively, and Ln = Gd (1), Tb (2), Ho (3), Er (4), and Yb (5) was synthesized. All five complexes were characterized by an elemental analysis, infrared spectroscopy, single crystal X-ray diffraction, and SQUID measurements. The complexes 1–5 in the series were all isostructural. A comparison of the temperature dependence of the dc magnetic susceptibility data of these complexes revealed clear differences depending on the lanthanide center. Ac magnetic susceptibility measurements revealed that none of the five complexes exhibited a slow magnetic relaxation under a zero applied dc field. On the other hand, the Kramers systems (complexes 4 and 5) clearly displayed a slow magnetic relaxation under applied dc fields, suggesting field-induced single-molecule magnets that occur through Orbach and Raman relaxation processes.

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