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The synthesis of potassium- and lithium-containing cyclic clusters has been carried out to study the influence of the alkali metal ion on the properties of the core of the clusters. Synthesizing the potassium clusters turned out to be a failure but lithium clusters were successfully derived. Results show that the metal ion in complexes 1 to 3 tunes the magnetism of the core. Its j value is related to the ionic radius of the guest ion which also determines the exact pattern at the bridging methoxide ligands.

The structure and magnetic properties of a mixed-valence heptanuclear manganese cluster, (Mn7(OMe)12(dbm)6)*CHCl3*14MeOH are examined. The structure and solid-state magnetic behavior of the dimeric complex (Mn(super III)(sub 2)(OMe)2(dbm)4) was also investigated. Proton NMR spectra in solution strongly support valence localization and indicate that the observed solid-state structure may be caused by static disorder effects.

A study was conducted to determine the spectroscopic characterization of a Schiff base diquinone ligand that formed two valence tautomeric species with cobalt ions having a transition temperature within room temperature. The Schiff base biquinone ligands were either denoted as Cat-N-BQ or Cat-N-SQ. The CoIII(Cat-N-BQ)(Cat-N-SQ) was the cobalt complex formulated and characterized. Results indicated that the cobalt complex manifested a valence tautomeric equilibrium in solution. The valence tautomerism distinguished a complex formed by a ligand containing a nitrogen donor atom.

The reaction of (N(CH3)sub4)OH with FeCl3 and thme in a methanolic medium gives (N(CH3)4)2(OFe6(H-3thme)3(OCH3)3Cl6).2Hsub2O, where thme = 1,1,1-tris(hydroxymethyl)ethane. The structure has three methoxo bridges, which link two Fe(III) units to six terminally coordinating Cl- ligands. Variable temperature magnetic susceptibility values show antiferromagnetic coupling for the hexanuclear complex core in a singlet ground state. The Fe-mu6-O-Fe interactions are unusually large, which are explained using molecular orbital calculations at the extended Huckel level.

Polymetallorganosiloxanolates form a class of nanoscale metal ion clusters. Two Cu complexes, Na4((PhSiO2)sub12Cu4).8nBuOH and K4((C2H3SiO2)sub12Cu4).6nBuOH have Cu-atoms present as Cu2O6 units and show a large antiferromagnetic exchange coupling. Whereas ((PhSiO2)sub6Cu6(O2SiPh)6).6EtOH has a sandwiched structure present in S = 3 ground state. Magnetic susceptibility and high frequency electron paramagnetic resonance are employed to study magnetic anisotropy in spin clusters.

Two nickel(II) tetranuclear complexes, Na2((PhSiO2)6Na4Ni4(OH)2(O2SiPh)6).16Bu(super n)OH and Na2((PhSiO2)6Ni6(O2SiPh)6Cl).12CH3OH.H2O, show ferromagnetic exchange-coupling interactions mediated by siloxanolate ligands. Four spin ground state and nil spin ground state values of spin were showed by the ferromagnetic complexes due to the presence of additional antiferromagnetic interactions via the encapsulated mu6-chloride ion. Potential of these complexes for developing new molecule-based materials is discussed.

Studies of two hexairon(III) clusters containing a mu6-oxo bridge reveal that the unusual bridging mode causes weak antiferromagnetic exchange-coupling interactions between the metal centers with J trans and J cis values of 19(2) and 9(1) per cm, respectively. The studies may be useful in the search for magneto-structural correlations in oxo-bridged polyiron aggregates.

The first example of an efficient enantioselective preparation of a chiral calix[4]arene bis-epoxide via a direct asymmetric reaction on the parent 1,3-diformylcalix[4]arene is reported. The results from the [super 1]H and [super 13]C NMR analyses reveal the presence of two biaryl epoxides in obtained compounds.

Single-crystal high-frequency electron paramagnetic resonance spectroscopy is used on an axial single molecule magnet in order to examine the origin of the transverse magnetic anisotropy. The results have shown the vital role played by the noncollinearity of the single-ion easy axes in the determination of high-order terms of the transverse magnetic.

The synthesis, structure and magnetic properties of an octacopper(II) cluster, [Cu6{(PhSio2)6}(sub 2){NCCu(Me6tren)} (sub 2)(MeOH)4](super 2+) are reported by using high-spin metallasiloxanes as templates for the controlled organization of specifically functionalized magnetic units. The value of metallasiloxane cages as building blocks for the synthesis of high-nuclearity clusters is generalized by the results of these studies and provides a simple way to design and isolate specifically

A ferromagnetic ring complex containing six manganese(III) ions was synthesized by simultaneous oxidation and methoxide-promoted aggregation. The result is a high-nuclearity transition-metal cluster containing 24 unpaired electrons. The process proves that magnetic properties of high-nuclearity clusters can be altered through the electronic structure of the metal ions constituting the complex.