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The total synthesis of borrelidin was carried out through regioselective methylation, directed hydrogenation, stereoselective reformatsky-type reaction and MgB[r.sub.2]*E[t.sub.2]-mediated chelation-controlled allylation. The results demonstrate that the initial samarium(II) iodide-mediated intramolecular reformatsky-type reaction using aldehyde was the most efficient route providing the shortest number of steps and the highest overall yield of the key intermediate.

In this study, damage evolution on Sm and O sublattices in gold implanted samarium titanate pyrochlore was studied by Rutherford backscattering spectroscopy and nuclear reaction analysis. The results showed that the atomic disorder on both the Sm and O sublattices increase nonlinearly with ion influence, eventually achieving a fully amorphous state.

Cooling-rate dependent ferromagnetism in samarium octacyanotung state, Sm(H2O)5[W(CN)8] is reported. X-ray single structural analysis showed that this compound consists of a two-dimensional cyanobridged network.

Sm-Co particles are produced in a W matrix by annealing sputtered Sm-Co/W multilayers with different thicknesses of 5-28 nm different temperatures. Formation of Co-W and Co-Si alloys is reflected by the reduction of the average magnetization of the samples.

A procedure by which annulations reactions of various dihalides with keto esters can be carried out to provide entry to eight- and nine- membered carbocycles is developed. This method allows one to employ sp(sub 2)-hybridized bromo derivatives for the incorporation of alkenyl or aryl moieties in the carbocycles.

A centered icosahedral 12-coordinated samarium cluster formed by six bis{L-prolinato)nickle- (II) (Ni(pro)(sub 2)l) ligands, [Sm{Ni(pro)(sub 2)}(sub 6)](super 3+) was prepared. It is reported that the reaction of SM with [Ni(pro)(sub 2) is a self-assembly.

The total synthesis of (-)-steganone using a samarium(II) iodide promoted 8-endo ketyl-olefin coupling.

A study concerning the synthesis and structures of the compounds LaCuSTe and SmCuSTe is presented. The band structures of two compound indicates that they are semiconductors.

Research was conducted to examine the absorption and fluorescence spectra of the (super 6)H(sub J), (super 6)F(sub J), (super 4)G(sub 5/2) and (super 4)F(3)(sub 3/2) multiplet manifolds of Sm3+ (4F)(super 5) as a dopant in crystals of strontium fluorapatite in terms of crystal-field splitting calculations. Calculations of radiative lifetime of (super 4)G(4)(sub 5/3) and the branching ratios were found to be in reasonable agreement with the experimental values derived from the experiment.

Research was conducted to examine an enantiospecific synthesis of (+)-nemorensic acid, a necic acid component of a macropyrrolizidine alkaloid nemorensine, isolated from Senecio nemorensis L. The regioselective fragmentation reaction of an epsilon-halo-alpha,beta-unsaturated ester with samarium iodide yielded a fragmentation product. Results demonstrate that the type of fragmentation with samarium iodide is unprecedented and that the approach developed should also be applicable to the synthesis of other types of necic acid components of macropyrrolizidine alkaloids.

A study was conducted to clarify the mechanism of the instability of the electric and magnetic properties in the rare earth nitrate crystal samarium nitrate hexahydrate. Deuterium nuclear magnetic resonance spectra and spin-lattice relaxation time were measured for this crystal. H nuclear magnetic resonance spectroscopy confirmed the existence of two kinds of waters, one being the crystallization water and the other being the coordinated water. Other results are discussed.

The effect of ratio z on the high temperature magnetic properties of Sm(Co, Fe, Cu, Zr)z magnets was investigated in range of ratio z values from 6.7 to 9.1. It was found that the lower the ratio z, the smaller the temperature coefficient of coercivity. When the ratio z changes from 7.0 to 8.5, the temperature coefficient of coercivity changes from -0.03% per degree C to -0.25% per degree C. Higher ratio z magnets were suitable for normal applications but not for high temperature applications due to their large temperature coefficient of coercivity.

The synthesis of Sm(II) complexes involving cyclooctatetraenide dianions and peralkylcyclopentadienide anions was studied. The [(C5Me5)-Sm(THF)x]+ ligand generated can be used to support new soluble organometallic divalent samarium complexes. The new complexes were analogous to the (C5Me5)2Sm(THF) (sub 2)2 and (C5-Me5)2Sm3 pair. These offered additional opportunities to study Sm(II) reduction mechanisms. Changes in the complexes suggested that ligand substitution can be used to change the bent nature of metallocenes to determine how this angle reflects reactivity.

Chemical evidences were examined to illustrate the chemical reduction activity of the sterically crowded molecule (C5Me5)3Sm. The molecule displayed extensive and multiple reactivity patterns. It can act as a bulky alkyl complex and participates in insertion, ring-opening chemistry, polymerization and hydrogenolysis in some substrates. The findings suggest that the one-electron reduction capacity of the molecule can be extended to other trivalent lanthanides.

The synthesis, structural characterization and reactivity of the unsolvated decamethylsamarocenium cation complex ((C5Me5)2Sm)(BPh4) are described. The complex was used to develop a convenient synthetic approach to unsolvated ((C5Me5)2Ln)(BPh4) cations of other lanthanides. The route involves the reaction of ((C5Me5)2Sm)(BPh4) with KC5Me5 in benzene. ((C5Me5)2Sm)(BPh4) was found to be highly reactive and a good precursor to other trivalent samarium complexes.

Samarium(II) iodide was used to facilitate a tandem intermolecular carbonyl addition/intramolecular nucleophilic acyl substitution sequence, producing seven- through nine-membered monocyclic, bicyclic and tricyclic systems with good yields and high diastereoselectivities. Such a tandem reaction is made up of an intermolecular reaction followed by an intramolecular ring expansion which results in a formal (m + n) cycloaddition, beginning from extremely simple, readily available substrates.

Samarium(II) iodide was used in a one-pot, three-step, nucleophilic acyl substitution/ketyl-olefin coupling/beta-elimination reaction sequence. This unique procedure combines two SmI2-mediated processes to allow the net delivery of an alkenyl moiety to a ketone carbonyl produced as an intermediate along the sequential reaction pathway. An interesting measure of stereocontrol over three to five contiguous stereocenters was found as a result of the superior facial selectivity conveyed in the ketyl-olefin coupling reaction.

Bond fission of the C-O bond of allylic benzyl ethers with Cp*2Sm(thf)n produced samarium complexes in good yields. Ease of cleavage was observed to be comparable to the corresponding propargylic ethers intermolecularly, but lower intramolecularly. Regio- and stereochemistry on the electrophilic trappings of the allylic complexes produced were dependent on the type of electrophiles. They reacted with carbonyl compounds exclusively from the most substituted terminus of the allylic moieties to produce blanched homoallylic alcohols with anti-diastereoselectivity.

Hydroxyalkylations of indole-3-carbonyls were performed through the help of an N-sulfonyl group or a cyano group at the C-2 position by the promotion of samarium diiodide. The indolecarbonyl coupling reactions occurred in high stereoselectivity through chelate transition states. Intramolecular indolecarbonyl couplings of 1-(3-oxopropyl)indole-3-carboxaldehydes were accomplished as the indolecarbonyl group was more reactive to SmI2 than the aliphatic carbonyl group.

The reactivity of CO2 and COS with divalent and trivalent organosamarium complexes was studied. (C5Me5)2Sm(THF)2 reductively coupled CO2 in THF at room temperature to produce the oxalate complex, ((C5Me5)2Sm)2(mu-eta2:eta2-O2CCO2), 1, in more than 90% yield. The metal centers in 1 were formally eight-coordinate. The reaction of COS with (C5Me5)2Sm(THF)2 resulted in a disproportionation product, (C5Me5)2Sm(mu-eta2:eta1-S2CO)Sm(C5Me5)2(THF), 2, which had one (C5Me5)2Sm unit involved in a four-membered SmSCS ring.

The cyanosilylation of a variety of benzaldehydes with samarium(III) chloride as catalyst is reported. Addition of the bis-phosphoramidate reagent was found to accelerate the reaction, but its use alone did not promote the cyanosilylation. Despite the fact that enantioselectivity of products was not very high, the approach still holds promise due to features such as cyanosilylation with acceptable enantioselectivity at room temperature, the use of very small amounts of SmCl3 and easy separation of the ligand from the mixture and its reuse in the cyanosilylation.

Phase transitions in rapidly quenched Sm(sub 10)Fe(sub 90) ribbons during an annealing treatment were investigated. One of these transitions is the transformation of the main phase from the amorphous state to the metastable CaCu(sub 5)-type Sm(Fe,Ti)5 and to the metastable TbCu(sub 7)-type Sm(Fe,Ti)7 was noted with the increasing annealing temperature. The impact of different Ti additions on structure and the magnetic properties of nitrides were also examined.