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In addition to previously studied {CuGd

The synthesis of a new {Ni

Homometallic {NiII4} cubane-like clusters with a rare chiral core have been prepared via the employment of enantiomerically pure 2-(1-hydroxyethyl)pyridine (Hmpm). Comparison with the achiral cubanes derived from the related 2-pyridinemethanol (Hpym) ligand reveals drastic structural changes as a consequence of the transfer of chirality from the ligands to the whole structure. Their magnetic properties have been related to the structural features of their cubane-type cores.

A new family of {Cu4Ln2} (Ln = Gd, Tb and Dy) complexes bearing the gem-diol form of di-2-pyridyl ketone [(py)2CO] ligand is reported. Magnetic studies reveal the presence of predominant ferromagnetic exchange interactions between the metal ions. As a result, the hexanuclear compounds exhibit single-molecule magnetism behavior and large magnetic entropy changes, depending on the 4f-metal ion present.

The employment of the fluorescent bridging and chelating ligand N-naphthalidene-2-amino-5-chlorobenzoic acid (nacbH2) in Ni(II) cluster chemistry has led to a series of pentanuclear and hexanuclear compounds with different structural motifs, magnetic and optical properties, as well as an interesting 1-D coordination polymer. Synthetic parameters such as the inorganic anion present in the NiX2 starting materials (X = ClO4(-) or Cl(-)), the reaction solvent and the nature of the organic base employed for the deprotonation of nacbH2 were proved to be structure-directing components. Undoubtedly, the reported results demonstrate the rich coordination chemistry of nacbH2 in the presence of Ni(II) metal ions and the ability of this chelate to adopt a variety of different modes, thus fostering the formation of high-nuclearity molecules with many physical properties.

The initial 'accidental', metal ion-assisted hydrolysis of PF6(-) to PO3F(2-) has been evolved in a systematic investigation of the bridging affinity of the latter group in Ni(II)/oximate chemistry; mono-, di- and trinuclear complexes have been prepared and confirmed both the rich reactivity of PO3F(2-) and its potential for further use as bridging ligand in high-nuclearity 3d-metal cluster chemistry.

The first use of the flexible Schiff base ligand N-salicylidene-2-aminocyclohexanol in metal cluster chemistry has afforded a new family of Ln7 clusters with ideal D(3h) point group symmetry and metal-centered trigonal prismatic topology; solid-state and solution studies revealed SMM and photoluminescence behaviors.

The targeted replacement of acetate groups in the optically inactive [Mn(III)3O(O2CMe)3(mpko)3](ClO4) single-molecule magnet with their naphthalene, anthracene, and pyrene fluorescent analogues has led to three new emissive SMMs with enhanced photoluminescence properties and potential applications in the field of molecular electronics.

Compound [Cu(3)(N(3))(6)(DMF)(2)](n) () was initially obtained in a serendipitous way during efforts to prepare a Cu(II)/N(3)(-)/Mebta coordination polymer (Mebta = 1-methylbenzotriazole). With the identity of established by single-crystal crystallography, a rational preparative route to this complex was designed and carried out by reacting Cu(ClO(4)).6H(2)O with two equivalents of NaN(3) in DMF. Complex is a 2D coordination polymer possessing mu(1,1,1) and mu(1,1,3) azido ligands. Its structure consists of {Cu(3)(N(3))(6)(DMF(2))} repeating units, which form chains that run parallel to the a axis; their bridging is achieved through end-on azides. The chains form sheets parallel to the ab plane through end-to-end azides. The magnetic properties of have been studied in detail. The complex contains 1D ferromagnetic chains, based on a Cu(II)(3) repeating unit, which can be viewed as having an S = 3/2 ground state. The ferromagnetic chains undergo antiferromagnetic coupling, which is weak enough to be overcome by moderate magnetic fields at 2 K leading to a metamagnetic spin-flop transition at 2.7 T. The transition is first-order, leading to hysteresis of the order of 0.2 T.

The initial employment of alpha-benzoin oxime (bzoxH2) in metal cluster chemistry has provided access to a new family of decanuclear CuII complexes with a loop or single-strand wheel topology; the CuII10 clusters are antiferromagnetically-coupled with an S=0 spin ground state, as expected for even-membered loop arrays of CuII atoms.

The use of the anion of 2,2-bis(hydroxymethyl)-2,2′,2″-nitrilotriethanol (‘bis-tris’ or LH5) as a chelate in Mn cluster chemistry is reported, and two products [Mn(N3)(LH3)] (1) and [Mn5(LH2)3(LH5)(MeOH)2.5]Cl4 (2) are described. The reaction of Mn(ClO4)2·6H2O and NaN3 with LH5 and NEt3 in a 1 : 1 : 1 : 2 molar ratio in DMF gave complex 1. The reaction of 1, NEt3 and MnCl2·4H2O in a 2 : 2 : 1 ratio in MeOH gave the pentanulear complex 2. Complex 1 contains a distorted-octahedral MnIII atom exhibiting a Jahn–Teller axial elongation. Complex 2 has a mixed-valence MnII2MnIII3 trigonal bipyramidal Mn5 topology, with the apical positions of the [Mn5(μ-OR)7]6+ core occupied by the MnII atoms. Variable-temperature, solid-state dc and ac magnetization studies are reported for 1 and 2 in the 1.8–300 K range. The data for 1 are as expected for a high-spin d4 MnIII complex with S = 2; at low temperature, the effects of zero-field splitting (ZFS) and intermolecular antiferromagnetic interactions viaOH⋯O hydrogen bonds become evident. Fitting of magnetization vs. field (H) and temperature (T) data by matrix diagonalization gave S = 2, D = −3.25 cm−1 and |E| = 0.32 cm−1, with g fixed at 2.00, where D and E are the axial and rhombic ZFS parameters, respectively. The analogous fit for 2 gave S = 3 and D = −0.68 cm−1. The combined results demonstrate the usefulness of ‘bis-tris’ as a new poly-alkoxide chelate for the synthesis of new Mn complexes.

The reactions of 2-pyridinealdoxime [(py)CHNOH] with Ni(ClO4)(2).6H2O in the presence of NaOH and NaN3 have led to Ni(II)14 and Ni(II)12Na2 clusters; the Ni14 compound is the biggest metal oxime cluster discovered to date, as well as the largest Ni azide cluster.