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1.
Dalton Trans ; 42(26): 9505-12, 2013 Jul 14.
Artigo em Inglês | MEDLINE | ID: mdl-23673773

RESUMO

Reaction of (NBu3H)3[W(CN)8]·H2O and linear trinuclear complexes [Cu(II)2L2Ln(III)(NO3)3] (L = 2,6-di(acetoacetyl)pyridine, Ln = Eu (1), Gd (2), Tb (3) and Dy (4)) leads to the formation of four one-dimensional (1D) complexes. Single crystal X-ray analysis reveals that [W(CN)8](3-) bridges between the [Cu(II)2L2Ln(III)] sub-building units to construct the alternative chains. Magnetic investigation indicates that ferromagnetic interaction occurred between all paramagnetic ions and the slow magnetic relaxation properties were observed in complexes 3 and 4.


Assuntos
Cobre/química , Elementos da Série dos Lantanídeos/química , Compostos Organometálicos/química , Piridinas/química , Compostos de Tungstênio/química , Fenômenos Magnéticos , Modelos Moleculares , Compostos Organometálicos/síntese química
2.
Inorg Chem ; 50(15): 6868-77, 2011 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-21718032

RESUMO

On the basis of high-spin metal-cyanide clusters of Mn(III)(6)M(III) (M = Cr, Fe, Co), three one-dimensional (1D) chain complexes, [Mn(salen)](6)[Cr(CN)(6)](2)·6CH(3)OH·H(2)O (1), [Mn(5-CH(3))salen)](6)[Fe(CN)(6)](2)·2CH(3)CN·10H(2)O (2), and [Mn(5-CH(3))salen)](6)[Co(CN)(6)](2)·2CH(3)CN·10H(2)O (3) [salen = N,N'-ethylenebis(salicylideneiminato) dianion], have been synthesized and characterized structurally as well as magnetically. Complexes 2 and 3 are isomorphic but slightly different from complex 1. All three complexes contain a 1D chain structure which is comprised of alternating high-spin metal-cyanide clusters of [Mn(6)M](3+) and a bridging group [M(CN)(6)](3-) in the trans mode. Furthermore, the three complexes all exhibit extended 3D supramolecular networks originating from short intermolecular contacts. Magnetic investigation indicates that the coupling mechanisms are intrachain antiferromagnetic interactions for 1 and ferromagnetic interactions for 2, respectively. Complex 3 is a magnetic dilute system due to the diamagnetic nature of Co(III). Further magnetic investigations show that complexes 1 and 2 are dominated by the 3D antiferromagnetic ordering with T(N) = 7.2 K for 1 and 9.5 K for 2. It is worth noting that the weak frequency-dependent phenomenon of AC susceptibilities was observed in the low-temperature region in both 1 and 2, suggesting the presence of slow magnetic relaxations.

3.
Dalton Trans ; 40(22): 5999-6006, 2011 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-21541410

RESUMO

Two hydroxo-bridged complexes, {[Mn(III)(3-CH(3)O)salen](2)[Cr(III)(salen)(OH)(2)]}ClO(4)·6H(2)O (1) and {[Mn(III)(5-CH(3))salen](2)(OH)}ClO(4)·3H(2)O (2) [salen = N,N'-ethylenebis(salicylideneiminato) dianion], have been synthesized by the hydrolysis of the corresponding Mn(III)(Schiff-Bases) derivatives and [Cr(salen)(H(2)O)(2)]Cl precursors. X-Ray structure characterization reveals the discrete linear arched trinuclear structure of 1 and the 1D chain arrangement of 2. Magnetic experimental data and density functional theory (DFT) calculations both indicate the dominant antiferromagnetic interaction mediated by the hydroxo-bridges in both 1 and 2. Frequency-dependent AC susceptibilities reveal slow relaxation of 1 in low temperature. It is worth noting that the structure and magnetic properties of 1 is comparable to a reported cyano-bridged SMM, K[(5-Brsalen)(2)(H(2)O)(2)Mn(2)Cr(CN)(6)]·2H(2)O.

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