New alkoxo-bridged mixed-valence cobalt clusters: Synthesis, crystal structures and magnetic properties

Tudor, Violeta; Marin, Geanina; Lloret, Francesc; Kravtsov, Victor Ch.; Simonov, Yurii A.; Julve, Miguel; Andruh, Marius

doi:10.1016/j.ica.2008.03.007

Cited by 53 publications

(33 citation statements)

References 72 publications

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“…Indeed, the values above correspond very well to those of related systems reported [31]. Of particular note, however, is the positive value of J, which is rare in binuclear Co(II) systems [32], although some cases of ferromagnetic coupling between Co(II) ions have been reported in multinuclear systems involving Co(II) and Co(III) centres [33,34]. In our binuclear complex, fitting of this parameter (J) was directly correlated with the rise in vT below 10 K. We were only able to reproduce this feature with positive values of J and not by any combination of the other parameters.…”

supporting

confidence: 83%

Structural and magnetic properties of the binuclear [Co2{(OPPh2)2N}4] complex: Ferromagnetic coupling between the two S=3/2 Co(II) ions

Ferentinos

Chatziefthimiou

Robertson

et al. 2009

Inorganic Chemistry Communications

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supporting

confidence: 83%

Structural and magnetic properties of the binuclear [Co2{(OPPh2)2N}4] complex: Ferromagnetic coupling between the two S=3/2 Co(II) ions

Ferentinos

Chatziefthimiou

Robertson

et al. 2009

Inorganic Chemistry Communications

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“…The two compounds, [Co II Co III ]), previously described by us [5]. Indeed, the structure of 1 (see Figure 1) can be seen as the result of replacing the three peripheral cobalt(II) ions from the related heptanuclear [Co II 4 Co III 3 ] motif by copper(II) ions.…”

Section: Resultsmentioning

confidence: 89%

“…When cobalt (II) or manganese(II) salts and aminoalcohols are employed as starting materials, mixed-valence Co II -Co III [3] and Mn II -Mn III [4] assemblies often result (the basicity of the aminoalcohols favors the oxidation of the divalent metal ions). In previous papers, we have reported on mixed-valence cobalt clusters of formula [Co II 4 Co III 3 (dea) 6 (CH 3 COO) 3 ](ClO 4 ) 0.75 (CH 3 COO) 1.25 [5] and [Co 4 II Co 2 III (dea) 2 (Hdea) 4 )(piv) 4 ](ClO 4 ) 2 [6] (H 2 dea = diethanolamine and Hpiv = pivalic acid) fwhich are obtained by using H 2 dea in the self-assembly processes. Within the first compound, characterized by a crystallographic three-fold inversion axis, the central cobalt(II) ion is surrounded by six peripheral cobalt atoms, three of them being divalent and the other three trivalent.…”

Section: Introductionmentioning

confidence: 99%

Heterometallic CoII-CoIII-MII alkoxido-bridged heptanuclear motifs (M = Cu, Zn). Syntheses, crystal structures and magnetic properties

Martin

Tudor

Mădălan

et al. 2018

Inorganica Chimica Acta

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Two new alkoxido-bridged heterometallic complexes of formula [Co II Co III 3 Cu II 3 (dea) 6 (CH 3 COO) 3 ](ClO 4) 0.75 (CH 3 COO) 1.25 (1) and [Co II 2 Co III 2 Zn II 3 (tea) 2 (piv) 6 (CH 3 O) 2 (OH) 2 (CH 3 OH) 2 ]•H 2 O 2 (H 2 dea = diethanolamine, H 3 tea = triethanolamine and Hpiv = pivalic acid) have been assembled using aminoalcohol ligands. The cationic core in 1 possesses a threefold crystallographic axis, and it exhibits a set of three copper(II), one cobalt(II) and three cobalt(III) ions arranged as a hexagon of alternating copper(II) and cobalt(III) ions around the central cobalt(II) ion. Each edge of the hexagon is defined by a double alkoxido bridge, the outer one being bis-monodentate with copper(II)cobalt(III) pair whereas the inner one adopts a tris-monodentate coordination mode linking the Cu(II)-Co(III) pair with the central cobalt(II) ion. The acetate groups act as bidentate ligands towards the copper(II) ions. The intramolecular cobalt(II)-copper(II) separation is 3.157 Å. A hexagon of two cobalt(II), two cobalt(II) and two zinc(II) ions distributed along three types of edges with a central zinc(II) ion occurs in 2. A tris-modentate alkoxido bridge is involved in all edges together with another bis-monodentate alkoxido bridge (Co III-Co II and Co II-Zn II pairs) and a carboxylate-pivalate bridge in the syn-syn conformation. The five coordination at each peripheral zinc(II) ion is completed by a monodentate carboxylate-pivalate ligand whereas a methoxo group allows to achieve the six-coordination at each cobalt(III) ion. The intramolecular cobalt(II)-cobalt(II) separation through the inner zinc(II) ion is 6.309 Å. The magnetic properties of 1 and 2 have been investigated in the temperature range 1.9-300 K. The exchange interaction between the six-coordinate cobalt(II) and copper(II) ions through the double alkoxido bridges in 1 and that between the six-coordinate cobalt(II) ions across the diamagnetic zinc(II) ion in 2 are found to be ferromagnetic [J = +5.39(5) (1) and +1.05(2) cm-1 (2)], the accidental orthogonality between the interacting magnetic orbitals accounting for this behaviour in the two cases.

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“…It was also shown that HBs can play an important role in magnetic exchange interactions [1][2][3]. At the same time results of density functional calculations on some dimeric Cu(II) complexes have shown that HBs in mediating magnetic exchange interactions exhibit essentially structural function as they enable to hold the paramagnetic central atoms relatively close to each other [4].…”

Section: Introductionmentioning

confidence: 99%

[Cu(men)2(BF4)2] (men=N-methyl-1,2-diaminoethane): Preparation, crystal structure, spectroscopic and magnetic properties

Černák

Haníková

Kuchár

et al. 2010

Journal of Molecular Structure

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New alkoxo-bridged mixed-valence cobalt clusters: Synthesis, crystal structures and magnetic properties

Cited by 53 publications

References 72 publications

Structural and magnetic properties of the binuclear [Co2{(OPPh2)2N}4] complex: Ferromagnetic coupling between the two S=3/2 Co(II) ions

Structural and magnetic properties of the binuclear [Co2{(OPPh2)2N}4] complex: Ferromagnetic coupling between the two S=3/2 Co(II) ions

Heterometallic CoII-CoIII-MII alkoxido-bridged heptanuclear motifs (M = Cu, Zn). Syntheses, crystal structures and magnetic properties

[Cu(men)2(BF4)2] (men=N-methyl-1,2-diaminoethane): Preparation, crystal structure, spectroscopic and magnetic properties

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