A useful preparation of ultrasmall iron oxide particles by using arc plasma deposition.

Ultrasmall particles, different from the larger size nanoparticles, have recently attracted significant attention in the scientific community in nanotechnology for catalytic, electronic and optical applications; however, their magnetic properties remain unexplored due to the difficult structural analysis. A challenging issue is to develop a preparation method for iron oxide particles (IOPs) with fine size control, and to determine the dependence of magnetic properties on the morphology and crystallinity of the magnetic particles. However, synthetic approaches to obtain IOPs, regarded as one of the new fields of magnetic nanoparticles, have been significantly limited.

Strong ferromagnetic exchange interactions in hinge-like Dy(O2Cu)2 complexes involving double oxygen bridges.

Two trinuclear isomeric compounds, [{(Cu(II)(salpn))(Me(CO)Me)}2Dy(III)(NO3)3] (1) and [{Cu(II)(salpn)}2Dy(III)(H2O)(NO3)3]·MeOH (2), along with one polymeric compound, {[{Cu(II)(salpn)}2Dy(III)(NO3)3bpy]·MeOH·H2O}n (3), were synthesized using a metalloligand, [Cu(II)(salpn)], where H2salpn and bpy stand for N,N'-bis(salicylidene)-1,3-propanediamine and 4,4'-bipyridine, respectively. Compounds 1 and 2 were selectively prepared with two solvents: the less polar acetone led to the exclusive crystallization of 1 with a transoid trinuclear architecture, while more polar solvent methanol provided sole construction of 2 with a cisoid trinuclear architecture. Compound 3 was prepared from 1 or 2 after bpy was introduced as a bridge.

Synthesis of mixed-valence hexanuclear Mn(II/III) clusters from its Mn(II) precursor: variations of catecholase-like activity and magnetic coupling.

One Mn(II) coordination polymer, [Mn(o-(NO2)C6H4COO)2(pyz)(H2O)]n (1), has been synthesized and oxidized with n-Bu4NMnO4 in non-aqueous media to two mixed-valence hexanuclear Mn(II/III) complexes [MnIII2MnII4O2(pyz)0.61/(MeOH)0.39(o-(NO2)C6H4COO)10·(H2O)·{(CH3)2CO}2]·(CH3)2CO (2) and [MnIII2MnII4O2(pyz)0.

A new family of trinuclear nickel(II) complexes as single-molecule magnets.

Three new trinuclear nickel (II) complexes with the general composition [Ni3 L3 (OH)(X)](ClO4 ) have been prepared in which X=Cl(-) (1), OCN(-) (2), or N3(-) (3) and HL is the tridentate N,N,O donor Schiff base ligand 2-[(3-dimethylaminopropylimino)methyl]phenol. Single-crystal structural analyses revealed that all three complexes have a similar Ni3 core motif with three different types of bridging, namely phenoxido (μ2 and μ3 ), hydroxido (μ3 ), and μ2 -Cl (1), μ1,1 -NCO (2), or μ1,1 -N3 (3). The nickel(II) ions adopt a compressed octahedron geometry.

Structure and magnetic properties of an unprecedented syn-anti μ-nitrito-1κO:2κO' bridged Mn(III)-salen complex and its isoelectronic and isostructural formate analogue.

The preparation, crystal structures and magnetic properties of two new isoelectronic and isomorphous formate- and nitrite-bridged 1D chains of Mn(III)-salen complexes, [Mn(salen)(HCOO)](n) (1) and [Mn(salen)(NO(2))](n) (2), where salen is the dianion of N,N'-bis(salicylidene)-1,2-diaminoethane, are presented. The structures show that the salen ligand coordinates to the four equatorial sites of the metal ion and the formate or nitrite ions coordinate to the axial positions to bridge the Mn(III)-salen units through a syn-antiμ-1κO:2κO' coordination mode. Such a bridging mode is unprecedented in Mn(III) for formate and in any transition metal ion for nitrite.