Three novel heterobimetallic Re(IV) compounds of formulae [ReBr4(µ-ox)M(4,7-Cl2phen)2]•CH3CN•CH3NO2 [M = Co(II) 1 and Ni(II) 2] and [ReBr4(ox)]3[CoIII(5,6-dmphen)3]2•CH3CN•2CH3NO2•4H2O 3 (ox = oxalate, 4,7-Cl2phen = 4,7-dichloro-1,10-phenanthroline and 5,6-dmphen = 5,6-dimethyl-1,10-phenanthroline) have been synthesised and the structures of 1 and 3 determined by single crystal X-ray diffraction. Compound 1 is an oxalato-bridged ReIVCoII heterodinuclear complex where [ReBr4(ox)]2- unit act as bidentate ligand towards the [Co(4,7-Cl2phen)2]2+ entity, the separation between Re(IV) and Co(II) across the oxalate being 5.482(1) Å. Compound 3 is an ionic salt whose structure is made up by [ReIVBr4(ox)]2- anions and [CoIII(5,6-dmphen)3]3+ cations plus acetonitrile, nitromethane and water as solvent molecules. The magnetic properties of 1-3 were investigated in the temperature range 1.9-300 K. Relatively large ferromagnetic interactions between Re(IV) and M(II) through the bis(bidentate) oxalato occurs in 1 and 2 [JReM = +11.0 (1) and +12.2 cm-1 (2), the Hamiltonian being defined as Ĥ = -JReM ŜRe . ŜM] which are explained on the basis of orbital symmetry considerations. A behaviour typical of a magnetically diluted Re(IV) complex with a large and positive value of zero-field splitting for the ground level (DRe = +43 cm-1) is observed for 3 in the high temperature range, whereas it exhibits spin canting in the low temperature domain as well as magnetic ordering below ca. 4.8 K.

Three novel heterobimetallic Re(IV) compounds of formulae [ReBr4(μ-ox)M(4,7-Cl2phen)2]·CH3CN·CH3NO2 [M = Co(II) (1) and Ni(II) (2)] and [ReBr4(ox)]3[CoIII(5,6-dmphen)3]2·CH3CN·2CH3NO2·4H2O (3) [ox = oxalate, 4,7-Cl2phen = 4,7-dichloro-1,10-phenanthroline and 5,6-dmphen = 5,6-dimethyl-1,10-phenanthroline] have been synthesised and the structures of 1 and 3 determined by single crystal X-ray diffraction. Compound 1 is an oxalato-bridged ReIVCoII heterodinuclear complex where the [ReBr4(ox)2 unit acts as a bidentate ligand towards the [Co(4,7-Cl2phen)2]2+ entity, the separation between Re(IV) and Co(II) across the oxalate being 5.482(1) Å. Compound 3 is an ionic salt whose structure is made up of [ReIV-Br4(ox)]2− anions and [CoIII(5,6-dmphen)3]3+ cations plus acetonitrile, nitromethane and water as solvent molecules. The magnetic properties of 1–3 were investigated in the temperature range 1.9–300 K. Relatively large ferromagnetic interactions between Re(IV) and M(II) through the bis(bidentate) oxalato occur in 1 and 2 [JReM = +11.0 (1) and +12.2 cm−1 (2), the Hamiltonian being defined as Ĥ = −JReM ŜRe·ŜM] which are explained on the basis of orbital symmetry considerations. A behaviour typical of a magnetically diluted Re(IV) complex with a large and positive value of zero-field splitting for the ground level (DRe = +43 cm−1) is observed for 3 in the high temperature range, whereas it exhibits spin canting in the low temperature domain as well as magnetic ordering below ca. 4.8 K.

Ferromagnetic coupling and spin canting behaviour in heterobimetallic ReIVMII/III (M = CoII/III, NiII) species

ARMENTANO, Donatella;DE MUNNO, Giovanni;
2013-01-01

Abstract

Three novel heterobimetallic Re(IV) compounds of formulae [ReBr4(µ-ox)M(4,7-Cl2phen)2]•CH3CN•CH3NO2 [M = Co(II) 1 and Ni(II) 2] and [ReBr4(ox)]3[CoIII(5,6-dmphen)3]2•CH3CN•2CH3NO2•4H2O 3 (ox = oxalate, 4,7-Cl2phen = 4,7-dichloro-1,10-phenanthroline and 5,6-dmphen = 5,6-dimethyl-1,10-phenanthroline) have been synthesised and the structures of 1 and 3 determined by single crystal X-ray diffraction. Compound 1 is an oxalato-bridged ReIVCoII heterodinuclear complex where [ReBr4(ox)]2- unit act as bidentate ligand towards the [Co(4,7-Cl2phen)2]2+ entity, the separation between Re(IV) and Co(II) across the oxalate being 5.482(1) Å. Compound 3 is an ionic salt whose structure is made up by [ReIVBr4(ox)]2- anions and [CoIII(5,6-dmphen)3]3+ cations plus acetonitrile, nitromethane and water as solvent molecules. The magnetic properties of 1-3 were investigated in the temperature range 1.9-300 K. Relatively large ferromagnetic interactions between Re(IV) and M(II) through the bis(bidentate) oxalato occurs in 1 and 2 [JReM = +11.0 (1) and +12.2 cm-1 (2), the Hamiltonian being defined as Ĥ = -JReM ŜRe . ŜM] which are explained on the basis of orbital symmetry considerations. A behaviour typical of a magnetically diluted Re(IV) complex with a large and positive value of zero-field splitting for the ground level (DRe = +43 cm-1) is observed for 3 in the high temperature range, whereas it exhibits spin canting in the low temperature domain as well as magnetic ordering below ca. 4.8 K.
2013
Three novel heterobimetallic Re(IV) compounds of formulae [ReBr4(μ-ox)M(4,7-Cl2phen)2]·CH3CN·CH3NO2 [M = Co(II) (1) and Ni(II) (2)] and [ReBr4(ox)]3[CoIII(5,6-dmphen)3]2·CH3CN·2CH3NO2·4H2O (3) [ox = oxalate, 4,7-Cl2phen = 4,7-dichloro-1,10-phenanthroline and 5,6-dmphen = 5,6-dimethyl-1,10-phenanthroline] have been synthesised and the structures of 1 and 3 determined by single crystal X-ray diffraction. Compound 1 is an oxalato-bridged ReIVCoII heterodinuclear complex where the [ReBr4(ox)2 unit acts as a bidentate ligand towards the [Co(4,7-Cl2phen)2]2+ entity, the separation between Re(IV) and Co(II) across the oxalate being 5.482(1) Å. Compound 3 is an ionic salt whose structure is made up of [ReIV-Br4(ox)]2− anions and [CoIII(5,6-dmphen)3]3+ cations plus acetonitrile, nitromethane and water as solvent molecules. The magnetic properties of 1–3 were investigated in the temperature range 1.9–300 K. Relatively large ferromagnetic interactions between Re(IV) and M(II) through the bis(bidentate) oxalato occur in 1 and 2 [JReM = +11.0 (1) and +12.2 cm−1 (2), the Hamiltonian being defined as Ĥ = −JReM ŜRe·ŜM] which are explained on the basis of orbital symmetry considerations. A behaviour typical of a magnetically diluted Re(IV) complex with a large and positive value of zero-field splitting for the ground level (DRe = +43 cm−1) is observed for 3 in the high temperature range, whereas it exhibits spin canting in the low temperature domain as well as magnetic ordering below ca. 4.8 K.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11770/131886
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 24
  • ???jsp.display-item.citation.isi??? 22
social impact