A Cu–Zn–Cu–Zn heterometallomacrocycle shows significant antiferromagnetic coupling between paramagnetic centres mediated by diamagnetic metal

Buvaylo, Elena A.; Kokozay, Vladimir N.; Vassilyeva, Olga Yu.; Skelton, Brian W.; Jezierska, Julia; Brunel, Louis Claude; Ozarowski, Andrew

doi:10.1039/b509810f

Cited by 60 publications

(51 citation statements)

References 14 publications

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“…The obtained values ⊥ > g g || point out that the unpaired electron is located in the 2 2 y x d − orbital, in accord with the squarepyramidal environment around the copper(II) centres [42]. With a rise of temperature, the number of binuclear copper(II) units of compound 1, that were excited from the ground spinsinglet state (S = 0) to the higher spin-triplet state (S = 1) grew up [39]. The spins S = 1 became magnetically diluted centres in the mainly diamagnetic lattice (S = 0).…”

Section: Epr Studymentioning

confidence: 51%

“…Fitting the Curie dependence to the experimental data reveals that 5.9% of the copper(II) ions in the sample of 1 are not coupled into dimers. The presence of the non-coupled copper(II) impurities(evidenced at the lowest temperatures through a slight increase in χ ) is a phenomenon common for this type of antiferromagnetic species[39].The coupling of two copper(II) ions through the oxalate-bridge makes a strong exchange interaction, with J = -295(2) and-294(2) cm -1 for 1 and 2, respectively. It is known that in the complexes with two square-pyramidal copper(II) centres and an entirely planar [LCu(magnetic orbital of copper(II) should be ideally directed towards the oxalate σ orbitals, and the antiferromagnetic interaction would be maximized (J from -280 to -400 cm -1 )[32a].…”

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confidence: 99%

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Synthesis, crystal structures and magnetic properties of the oxalate-bridged single CuIICuII and cocrystallized CuIIZnII systems. Three species (CuCu, CuZn, ZnZn) in the crystalline lattice

et al. 2015

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Two novel oxalate-bridged species: homometallic Cu II Cu II , [{Cu(bpy)Cl} 2 (µ-C 2 O 4 )] (1) and heterometallic Cu II Zn II , [CuZn{(bpy)Cl} 2 (µ-C 2 O 4 )] (2) (bpy = 2,2'-bipyridine), were synthesized and characterized by elemental analyses, IR and EPR spectroscopy, magnetic susceptibility measurements and single-crystal X-ray diffraction studies. The compounds crystallise in the same, triclinic 1 P space group. Their crystal structures consist of the binuclear entities [M(bpy)Cl(µ-C 2 O 4 )M(bpy)Cl] [M = Cu 2+ (1); M = Cu 2+ and/or Zn 2+ (2)] linked by the intermolecular π···π stacking interactions. Highly unusual, compound 2 is a cocrystallized system containing three types of mutually analogous entities: [Cu(bpy)Cl(µ-C 2 O 4 )Cu(bpy)Cl] (CuCu; the same unit as in 1), [Cu(bpy)Cl(µ-C 2 O 4 )Zn(bpy)Cl] (CuZn) and [Zn(bpy)Cl(µ-C 2 O 4 )Zn(bpy)Cl] (ZnZn), randomly distributed throughout the crystalline lattice in the molar ratio near to 1 : 2 : 1, respectively. Each metal atom in both 1 and 2 displays a square-pyramidal coordination involving two N atoms from the coordinated 2,2'-bipyridine ligand and two O atoms from the bridging oxalate group in the basal plane, and one chlorine atom in the apical position. Magnetization measurements, supported also by the EPR study, reveal a strong antiferromagnetic exchange interaction (J = -295(2) and -294(2) cm -1 , for 1 and 2, respectively; H = -JS 1 ·S 2 ) between two copper(II) ions through the oxalate bridge.

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Section: Epr Studymentioning

confidence: 51%

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confidence: 99%

Synthesis, crystal structures and magnetic properties of the oxalate-bridged single CuIICuII and cocrystallized CuIIZnII systems. Three species (CuCu, CuZn, ZnZn) in the crystalline lattice

et al. 2015

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“…0.027 cm 3 K mol −1 at 2 K. On the other hand, the χ m vs T curve provides more information about the magnetic behavior of complex 1: the χ m value of 0.034 cm −3 mol at room temperature increases as the temperature decreases, arriving at a maximum value of 0.082 cm −3 mol at 45 K; χ m then decreases practically to 0.012 cm −3 mol at 3 K before increasing a value of 0.013 cm −3 mol at 2 K. This behavior clearly indicates a typical antiferromagnetic coupling and the presence of a small amount of paramagnetic impurities. 17 The reciprocal molar magnetic susceptibility data obey the Curie−Weiss law in the high temperature region of 50−300 K with a Curie constant of C = 14.46 cm 3 K mol −1 and a Weiss constant of θ = −113.92 K. The negative value of the Weiss temperature, together with the curve of χ m T (T), indicates the presence of strong antiferromagnetic coupling between nickel(II) ions.…”

Section: ■ Results and Discussionmentioning

confidence: 98%

Self-Assembly of Thiacalix[4]arene-Supported Nickel(II)/Cobalt(II) Complexes Sustained by in Situ Generated 5-Methyltetrazolate Ligand

Xiong

Jiang

Gai

et al. 2012

Crystal Growth & Design

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Solvothermal reactions of thiacalix[4]arene, NaN 3 , and acetonitrile in the presence of nickel(II)/cobalt(II) salts yielded four discrete complexes sustained by the in situ generated 5-methyltetrazolate ligand, [Ni II 12 (PTC4A) 3 (μ 6 -CO 3 ) 2 (μ-Mtta) 2 (μ-Mtta) 4 (μ 4 -Mtta) 2 (Py) 4 ]·7DMF·2Py·dma (1), [Co II 12 (PTC4A) arene; H 4 BTC4A = p-tert-butylthiacalix[4]arene; HMtta = 5-methyl tetrazolate). Crystal structural analyses revealed that complexes 1−3 are stacked by pseudotrigonal planar entities, which consist of three metal II 4 -thiacalix[4]arene subunits including two shuttlecock-like and one cylinder-like ones. These subunits are connected in an up-to-down-to-up fashion through six different 5-methyl tetrazolate anions. Both the in situ generated 5-methyl tetrazolate anion and carbonato anion play an important role in constructing these high-nuclearity clusters. When the corresponding chloride salt was used as precursors in the synthesis, complex 4 was obtained, which is stacked by wheel-like entities possessing four shuttlecock-like building blocks linked by eight in situ generated 5-methyl tetrazolate ligands in an up-to-up fashion. The differences in the structures of complexes 3 and 4 indicate that the geometry and size of the corresponding anions together with their coordinating properties are essential in determining the final structures. The magnetic properties of complexes 1−4 were examined, indicating strong antiferromagnetic interactions between the nickel(II)/cobalt(II) ions in the temperature range of 50−300 K. ■ INTRODUCTIONIn the past few decades, the design and synthesis of novel coordination architectures with in situ generated ligands under hydro(solvo)thermal conditions is a field of great interest in coordination and organic chemistry for the discovery of fascinating organic reactions and novel coordination complexes. 1 A large number of coordination complexes with an intriguing variety of architectures, topologies, and novel properties have been well prepared by in situ metal−ligand reactions under hydro(solvo)thermal conditions. Among the in situ reactions, tetrazoles are prepared through [2 + 3] cycloaddition reaction of nitriles and azide with the aid of a Lewis acid such as a zinc salt reported in 2001. 2 Since then, tetrazole-based ligands have been demonstrated to be excellent and versatile building blocks, with charge and multiconnectivity ability, to produce multidimensional coordination polymers with interesting optical, ferroelectric, magnetic, and hydrogen storage properties and potential energetic applications. 3 Up to now, the synthetic approach has been extended by varying transition metal ions and especially d 8 /d 10 metal ions (such as Zn II , 3a,c,g,k Cd II , 3g,a,e3b,d,k,m Hg II , 3m Cu I , 3h,i and Ag I3g ) have been investigated extensively. However, other paramagnetic transition metal ions (such as Cu II , 3m,g Mn II , 3f,j,l Co II , 3l,m and Ni II3k,m ) have rarely been explored. In addition, a few examples based on presynthesized tetrazoles and paramagne...

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“…The cyclic motif 2M4‐1 is an evolution (Table 1) of the consecutive motif 1,2M4‐1 described above and exemplified by complexes 6 – 9 . The heterometallic Cu/Zn coordination compound 10 ,20 the structure of which belongs to the cyclic motif 2M4‐1 , was obtained by reaction (17).…”

Section: Complexes Of Tetranuclear Structuresmentioning

confidence: 99%

Polynuclear Heterometallic Complexes from Metal Powders: The “Direct Synthesis” Approach

et al. 2014

Self Cite

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The synthesis of polynuclear coordination compounds, particularly heterometallic coordination compounds, remains a challenge for modern chemistry. Spontaneous self‐assembly (SSA) is a primary approach that proceeds by broad screening, typically with simple, flexible ligands and available metal salts. The “direct synthesis” is a class of SSA, but prescribes the use of zero‐valent metal(s) as a starting material, typically oxidized by air oxygen, which results in a deficiency of anions in the reaction mixture and forces deprotonation of the protic ligand(s) with the formation of unexpected products. The “direct synthesis” approach has been successfully applied to the preparation of heterometallic complexes, which has allowed the isolation of numerous complexes, many with uncommon structures. In this review we summarize our experience in the field of the “direct synthesis” of polynuclear heterometallic complexes, covering preparative and structural aspects as well as applications of the compounds obtained.

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A Cu–Zn–Cu–Zn heterometallomacrocycle shows significant antiferromagnetic coupling between paramagnetic centres mediated by diamagnetic metal

Abstract: An unprecedented antiferromagnetic exchange mediated by two -O-Zn-O- bridges, with singlet-triplet splitting J= 35.0 cm-1, was observed between two copper centers separated by 5.7062(9)A in the heterometallomacrocyclic diethanolamine (H2L) complex [Cu2Zn2(NH3)2Br2(HL)4]Br2.CH3OH.

Cited by 60 publications

References 14 publications

Synthesis, crystal structures and magnetic properties of the oxalate-bridged single CuIICuII and cocrystallized CuIIZnII systems. Three species (CuCu, CuZn, ZnZn) in the crystalline lattice

Synthesis, crystal structures and magnetic properties of the oxalate-bridged single CuIICuII and cocrystallized CuIIZnII systems. Three species (CuCu, CuZn, ZnZn) in the crystalline lattice

Self-Assembly of Thiacalix[4]arene-Supported Nickel(II)/Cobalt(II) Complexes Sustained by in Situ Generated 5-Methyltetrazolate Ligand

Polynuclear Heterometallic Complexes from Metal Powders: The “Direct Synthesis” Approach

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