Azido­(methanol)[N,N′-(o-phenyl­ene)bis­(pyridine-2-carboxamidato)]manganese(III)

In the title complex, [Mn(C18H12N4O2)(N3)(CH4O)], the MnIII ion is in a distorted octa­hedral coordination environment. In the crystal structure, inter­molecular O—H⋯O hydrogen bonds connect mol­ecules into centrosymmetric dimers

A New Quinoxalinyl-Substituted Nitronyl Nitroxide Radical and its Five-Spin Cu-II and Four-Spin Mn-II Complexes: Syntheses, Crystal Structures, and Magnetic Properties

National Natural Science Foundation of China [21101096, 90922032, 21071085, 20971072]; NSF of Tianjin [09JCYBJC05500]; Research Fund for the Doctoral Program of Higher Education [20100031120013]; Fundamental Research Funds for the Central UniversitiesA new radical of QNXL-2NIT (1) (QNXL-2NIT = 2-(2-quinoxalinyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide) and its complexes [Cu(hfac)(2)](3)(QNXL-2NIT)(2)center dot 2CHCl(3) (2) and [Mn(hfac)(2)](2)(QNXL-2NIT)(2) (3) (hfac = 1,1,1,5,5,5-hexfluoroacetylacetone) were first reasonably designed and synthesised in this paper. The X-ray structure determination revealed that by introducing the quinoxalinyl ring group to the nitronyl nitroxide radical, QNXL-2NIT affords more coordination sites for metal ions. We successfully obtained its copper complex with linear tri-nuclear five-spin structure. However, when we substituted Mn-II as the central metal, complex 3 exhibits a rectangle-like four-spin framework containing two Mn-II ions and two radicals in one molecule. The magnetic study of the two complexes shows that there are strong antiferromagnetic interactions between the radical and the terminal Cu-II ions with g = 2.25, J = -291.67 cm(-1) and zJ(1) = -0.25 cm(-1) and the dominating interactions between the Mn-II ion and the radical in complex 3 are also antiferromagnetic with the parameters of g 1.99, J(1) = -77.00 cm(-1) and J(2) = 0.34 cm(-1)

Single-molecule magnets based on rare earth complexes with chelating benzimidazole-substituted nitronyl nitroxide radicals

National Natural Science Foundation of China [20971072, 91122013, 90922032]Three rare earth-nitronyl nitroxide radical complexes [Ln(tfa)(3)(NIT-BzImH)] (Ln(III) = Gd 1, Tb 2, Dy 3; tfa = trifluoroacetylacetonate; NIT-BzImH = 2-(2'-benzimidazolyl)-4,4,5,5-tetramethylimidazolyl-1-oxyl-3-oxide) have been successfully prepared and structurally characterized. X-Ray crystallographic analysis reveals that all three complexes are isomorphous. Their crystal structures consist of mononuclear molecule units in which lanthanide(III) is 8-coordinated to one NIT-BzImH and three trifluoroacetylacetonate ligands. The NIT-BzImH acts as a bidentate ligand via its nitrogen atom of the imidazole ring and the oxygen atom of the N-O group. The magnetic properties of complexes 1-3 were studied. All the three complexes exhibit ferromagnetic Ln(III)-radical coupling. AC magnetic susceptibility studies of 2 and 3 show slow magnetic relaxation suggesting that they behave as SMMs

K10[Co4(H2O)2(B-α-SiW9O34H)2]·21H2O : a sandwich polyoxometalate based on the magnetically interesting element cobalt

The magnetism of a sandwich tetracobalt(II) substituted tungstosilicate K10[Co4(H2O)2(B-α-SiW9O34H)2] · 21H2O has been studied based on an isotropic Heisenberg model supplemented by a zero-field splitting term.Accepted versio

Hetero-tri-spin 2p-3d-4f] Chain Compounds Based on Nitronyl Nitroxide Lanthanide Metallo-Ligands: Synthesis, Structure, and Magnetic Properties

Employing nitronyl nitroxide lanthanide(III) complexes as metallo-ligands allowed the efficient and highly selective preparation of three series of unprecedented heterotri-spin (Cu Ln-radical) one-dimensional compounds. These 2p-3d-4f spin systems, namely Ln(3)Cu(hfac)II(NitPhOAII)41 (Ln(III)=Gd 1(Gd), Tb 1(Tb), Dy 1(Dy); NitPhOAII=2-(4'-allyloxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3- oxide), Ln(3)Cu(hfac)II(NitPhOPO4] (1-nrn=Gd 2Gd, Tb 2Tb, Dy 2(Dy), Ho 2HOf Yb 2yb; NitPhOPr= 2-(4'-propoxyphenyI)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide) and Ln3Cu(hfac)II(NitPhOB441 (LnIm=Gd 3Gd, Tb 3Tb, Dy 3(Dy); NitPhOBz=2-(4'-benzyloxy- phenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide) involve O-bound nitronyl nitroxide radicals as bridging ligands in chain structures with a Cu-Nit-Ln-Nit-Ln-Nit-Ln-Nit] repeating unit. The dc magnetic studies show that ferromagnetic metal radical interactions take place in these heterotri-spin chain complexes, these and the next-neighbor interactions have been quantified for the Gd derivatives. Complexes 1Tb and 2Tb exhibit frequency dependence of ac magnetic susceptibilities, indicating single-chain magnet behavior