Mn7 and Mn12 Clusters From Use of 2-(Pyridine-2-yl)propan-2-ol: A New Half-Integer Single-Molecule Magnet

A new member of a class of rod-like Mn12 single molecule magnets using 2-(pyridine-2-ly)propan-2-ol

This paper reports on the synthesis, structure and magnetic properties of a new type of rod like Mn₁₂ metal cluster, [Mn₁₂O₇(OH)₂(OMe)₂(dmhmp)₄(O₂CPh)₁₁(H₂O)] (6) where the ligand (dmhmpH) is 2-(pyridine-2-yl)propan-2-ol. Compound (6) was obtained by reacting MnCl₂·4H₂O with dmhmpH in the presence of benzoic salt and Et₃N. The resulting crystalline material is assigned to the triclinic space group P1̄. Although compound (6) displays ferromagnetic and antiferromagnetic competition behavior, this does not prevent the molecule from functioning as a single-molecule magnet (SMM). The SMM behavior is evidenced by observing frequency dependent out-of-phase ac signals as well as magnetization hysteresis loops at low temperatures in a micro-SQUID study. A brief comparison between all rod-like Mn₁₂ materials is also given in the manuscript.

Solvent-induced structural diversity in tetranuclear Ni(ii) Schiff-base complexes: the first Ni4single-molecule magnet with a defective dicubane-like topology

The tetranuclear Ni^IIcomplexes with the Ni₄O₄cubane-like core (1) and the Ni₄O₆defective dicubane core (2) were studied, and the latter identified as a first single-molecule magnet with such topology.

DNA/protein interaction, cytotoxic activity and magnetic properties of amino-alcohol Schiff base derived Cu(ii)/Ni(ii) metal complexes: influence of the nuclearity and metal ions

The reactions of amino-alcohol derived Schiff-base ligands with Cu(ii) and Ni(ii) salts have afforded four novel polynuclear complexes, which exhibited interesting magnetic and cytotoxic properties.

Synthesis, crystal structures and magnetic properties of a family of manganese phosphonate clusters with diverse structures

Four manganese clusters containing tert-butylphosphonate ligands with diverse structures have been synthesized and characterized.

A comparative synthetic, magnetic and theoretical study of functional M₄Cl₄ cubane-type Co(II) and Ni(II) complexes

We describe the synthesis, structures, and magnetochemistry of new M4Cl4 cubane-type cobalt(II) and nickel(II) complexes with the formula [M(μ3-Cl)Cl(HL·S)]4 (1: M = Co; 2: M = Ni), where HL·S represents a pyridyl-alcohol-type ligand with a thioether functional group, introduced to allow subsequent binding to Au surfaces. Dc and ac magnetic susceptibility data of 1 and 2 were modeled with a full spin Hamiltonian implemented in the computational framework CONDON 2.0. Although both coordination clusters 1 and 2 are isostructural, with each of their transition metal ions in a pseudo-octahedral coordination environment of four Cl atoms and N,O-donor atoms of one chelating HL·S ligand, the substantially different ligand field effects of Co(II) and Ni(II) results in stark differences in their magnetism. In contrast to compound 1 which exhibits a dominant antiferromagnetic intramolecular coupling (J = -0.14 cm(-1)), 2 is characterised by a ferromagnetic coupling (J = +10.6 cm(-1)) and is considered to be a single-molecule magnet (SMM), a feature of special interest for future surface deposition studies. An analysis based on density functional theory (DFT) was performed to explore possible magnetostructural correlations in these compounds. Using a two-J model Hamiltonian, it revealed that compound 1 has four positive and two (small) negative J(Co···Co) isotropic interactions leading to a S(HS) = 6 ground state. Taking into account the magnetic anisotropy, one would recover a M(S) = 0 ground state since D > 0 from computations. In 2, all the J constants are positive and, in this framework, the zero-field splitting energy characterising the axial anisotropy was estimated to be negative (D = -0.44 cm(-1)). The computational results are consistent with compound 2 being an SMM.

Synthesis of an S(T) = 7 [Mn3] mixed-valence complex based on 1,3-propanediol ligand derivatives and its one-dimensional assemblies

Controlled organization of high-spin complexes and single-molecule magnets is a great challenge in molecular magnetism in order to study the effect of the intercomplex magnetic interactions on the intrinsic properties of a given magnetic object. In this work, a new S(T) = 7 trinuclear mixed-valence Mn complex, [Mn(III)Mn(II)2(LA)2(Br)4(CH3OH)6] ·Br·(CH3OH)(1.5)·(H2O)(0.5) (1), is reported using a pyridinium-functionalized 1,3-propanediol ligand (H2L(A)Br = 1-(3-bromo-2,2-bis(hydroxymethyl)propyl)pyridinium bromide). Using azido anions as bridging ligands and different pyridinium-functionalized 1,3-propanediol ligands (H2L(B)Br = 1-(3-bromo-2,2-bis(hydroxymethyl)propyl)-4-picolinium bromide; H2L(C)Br = 1-(3-bromo-2,2-bis(hydroxymethyl)propyl)-3,5-lutidinium bromide), the linear [Mn(III)Mn(II)2L2X4](+) building block has been assembled into one-dimensional coordination networks: [Mn(III)Mn(II)2(LA)2(Br)4(CH3OH)4(N3)]·((C2H5)2O)1.25 (2∞), [Mn(III)Mn(II)2(L(B))2(Br)4(C2H5OH)(CH3OH)(H2O)2(N3)]·(H2O)0.25 (3∞), and [Mn(III)Mn(II)2(L(C))2(Cl)(3.8)(Br)(0.2)(C2H5OH)3(CH3OH)(N3)] (4∞). The syntheses, characterization, crystal structures, and magnetic properties of these new [Mn3]-based materials are reported.