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Titolo:
Syntheses, structures, magnetic, and spectroscopic properties of cobalt(II), nickel(II) and zinc(II) complexes containing 2-(6-methyl)pyridyl-substituted nitronyl and imino nitroxide
Autore:
Yamamoto, Y; Suzuki, T; Kaizaki, S;
Indirizzi:
Osaka Univ, Grad Sch Sci, Dept Chem, Osaka 5600043, Japan Osaka Univ Osaka Japan 5600043 Sch Sci, Dept Chem, Osaka 5600043, Japan
Titolo Testata:
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS
fascicolo: 19, , anno: 2001,
pagine: 2943 - 2950
SICI:
1472-7773(20011007):19<2943:SSMASP>2.0.ZU;2-3
Fonte:
ISI
Lingua:
ENG
Soggetto:
CRYSTAL-STRUCTURES; FERROMAGNETIC INTERACTIONS; METAL-IONS; SPECTRA; RADICALS; LIGAND;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
32
Recensione:
Indirizzi per estratti:
Indirizzo: Kaizaki, S Osaka Univ, Grad Sch Sci, Dept Chem, Osaka 5600043, Japan OsakaUniv Osaka Japan 5600043 ept Chem, Osaka 5600043, Japan
Citazione:
Y. Yamamoto et al., "Syntheses, structures, magnetic, and spectroscopic properties of cobalt(II), nickel(II) and zinc(II) complexes containing 2-(6-methyl)pyridyl-substituted nitronyl and imino nitroxide", J CHEM S DA, (19), 2001, pp. 2943-2950

Abstract

Chelate complexation of 4,4,5,5-tetramethyl-2-(6-methyl-2-pyridyl)imidazolin-1-oxyl 3-oxide (NITmepy) and 4,4,5,5-tetramethyl-2-(6-methyl-2-pyridyl)imidazolin-1-oxyl (IMmepy) to cobalt(II) chloride (bromide) or zinc(II) chloride afforded tetrahedral four-co-ordinate (T-4) complexes, [MX2(NITmepy)] and [MX2(IMmepy)] (MX = CoCl (1 and 2), CoBr (1Br and 2Br) or ZnCl (3 and 4), respectively) containing either a six- or a five-membered chelate ring as determined by single-crystal X-ray analysis. The formation of such T-4 complexes arises from the steric requirements of the methyl group at the o-position of the pyridyl-N donor. The UV-vis-NIR spectra suggest that both complexes 1 and 2 in dichloromethane retain their solid state structure. In acetonitrile, however, 1 exists as an equilibrium mixture due to dissociationof the co-ordinated NITmepy, while 2 is stable. The ligand-field spin-allowed and spin-forbidden d-d transitions of 1 and 2 are not influenced by thecoordinated radical ligands. The reaction of nickel(II) chloride and thiocyanate with IMmepy gave a dichloro-bridged dinuclear complex with a square pyramidal five-co-ordinate (SPR-5) geometry and an OC-6 complex, respectively, [{NiCl(IMmepy)}(2)(mu -Cl)(2)] (5) and [Ni(NCS)(2)(IMmepy)(2)] (6). Theintramolecular magnetic interactions in I and 2 are estimated to be antiferromagnetic, whereas 5 and 6 give ferromagnetic interactions. Complex 3, with one-dimensional columns, forms a dimer so that a moderate intermolecularantiferromagnetic coupling is demonstrated, while complex 4 exists as a discrete molecule in the crystal and shows paramagnetic behaviour.

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Documento generato il 20/01/20 alle ore 10:27:47