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The synthesis and characterization of the organotin compounds [(n-C(4)H(9))(2)Sn(cys)] (1), [(C(6)H(5))(2)Sn(cys)] (2), [(C(6)H(5))(3)Sn(Hcys).(H(2)o)] (3), {[(CH(3))(2)Sn(Kcys)(2)].2(H(2)0)} (4), {[(n-C(4)H(9))(2)Sn(Kcys)(2)].2(H(2)0)} (5) and {[(C(6)H(5))(2)Sn(Kcys)(2)].2(H(2)0)} (6) (where H(2)cys = L-cysteine) are reported. The compounds have been characterized by elemental analysis and (1)H-NMR, Uv-Vis, FT-IR and MOssbauer spectroscopic techniques. Attempted recrystallization of (2) in DMSO/methanol 2:1 solution yielded after several days unexpectedly the dimeric compound bis(tri-phenyltin)sulphide {[(C(6)H(5))(3)Sn](2)S} (7) which has been characterized by x-ray analysis. The structure of the parent complex (2) as well as the mechanism of the decomposition of cysteine are being further investigated. The in vitro anticancer activity of complexes (I)- (6), against human leukemia (HL60), human liver (Bel7402), human stomach (BGC823) and human cervix epithelial human carcinoma (Hela), nasopharyngeal carcinoma (KB) and lung cancer (PG) tumor cells, were evaluated.

The magnetization reversal is studied in magnetron sputtered artificial superstructures of the form [Ni/Pt](6)/Pt(x)/[Co/Pt](6) with perpendicular anisotropy, in which the [Co/Pt](6) stacks have higher coercivity than the [Ni/Pt](6). For x >= 2 nm the two stacks reverse separately and exhibit characteristic stepped loops with a "plateau'' in the region between the two switching fields. First-Order Reversal Curves (FORCs) reveal that the maximum coupling is obtained for x=1.5 nm. While each of the Ni/Pt and Co/Pt stacks by itself is thin enough to reverse in large domains when they are coupled, formation of maze like domains is observed. In this case some reversibility of the demagnetization curves associated with interfacial domain wall pinning appears while in the rest of the cases the reversal mechanism is based on lateral domain wall pinning with low reversibility. In the loops monitored by Extraordinary Hall Effect (EHE) measurements this "plateau'' appears as a hump due to the different sign of the EHE coefficient between the [Ni/Pt](6) and [Co/Pt](6). (C) 2011 Elsevier B.V. All rights reserved. Journal of Magnetism and Magnetic Materials

The effect of magnetic field annealing of magnetron sputtered CoPt alloy films and Co/Pt bilayers on the crystallographic texture of the obtained chemically ordered (L1(0)) CoPt films is presented. In CoPt alloy films the main effect of the magnetic field is to suppress (1 1 1) growth in the early stages of L1(0) formation whereas the development of (0 0 1) versus (1 0 0) texture is related to chemical ordering strain. A higher degree of (0 0 1) texture is obtained by magnetically annealing Co/Pt bilayers since the initial (1 1 1) texture in the as-sputtered films is avoided and Co-Pt alloying occurs in the presence of the magnetic field. (C) 2010 Elsevier B.V. All rights reserved. Journal of Magnetism and Magnetic Materials

The synthesis and the structural investigation of triorganostannyl esters of the 3- and 4-[1-pyridin-2-yl-methylidene]- and 3,5-bis-[1-pyridin-2-yl-methylidene]-benzoic acids are reported with methyl, n-butyl, cyclohexyl, phenyl and benzyl substituents on tin. The organic carboxylates may be considered as iminopyridines emerging from the condensation of the corresponding aminobenzoic acid with pyridine-2-carboxaldehyde. In this respect it is interesting to investigate their physicochemical properties since their coordination to metal centers will affect both the photophysical properties of the metal and the conformation and intermolecular interactions of the ligands. Therefore, the structure of the above triorganotin compounds is studied and discussed in relation to those of the unsubstituted benzoates as well as of the free ligands. X-ray crystallography and a coalescence of spectroscopic methods applied both in the solid state and in Solution have been used in this effort. (C) 2009 Elsevier B.V. All rights reserved. Journal of Molecular Structure

Spinel iron oxide nanoparticles capped with organic molecules have been successfully prepared and used to produce iron oxide nanoparticles-single wall carbon nanotubes hybrid materials, which were characterized by a number of experimental techniques. The nanoparticles in both samples have an average particle size of about 10 nm and acquire a chemical composition of the type Fe3-xO4, with 0

In the present work we employed various transition metals (Cr, Mn, Fe, Co, Ni, Cu and Zn) loaded on different smectite clays (laponite and montmorillonite) as catalysts in synthesis of carbon nanostructures (mainly nanotubes) and we report the effect of the nature of the catalytic centers and type of aluminosilicate layers in the morphology, quality and structure on the final products. Owing to their unique swelling, ion-exchange and intercalation properties smectite clays were easily. uniformly and reproducibly loaded with metal cations. Different homoionic forms of montmorillonite and laponite were prepared containing first-row transition metals and the synthesis of carbon nanostructures was carried out at 700 degrees C using an acetylene/nitrogen mixture. A variety of analytical techniques (XRD, Raman. SEM, TEM and thermal analysis) were used to fully characterize the final materials. Iron-, cobalt-, nickel- and manganese-exchanged clays showed to be effective catalysts for the production of carbon nanotubes, while acetylene decomposition over copper-exchanged clays resulted to the creation of carbon spheres. The resulting hybrid systems are particularly attractive for polymer reinforcing applications since the combined action of clay-carbon nanotubes in polymer matrixes can provide outstanding properties to the resulting composite materials. (C) 2008 Elsevier B.V. All rights reserved. Materials Science and Engineering B-Advanced Functional Solid-State Materials

Four organotin(IV) complexes with the heterocyclic thioamides 2-mercapto-4-methyl-pyrimidine hydrochloride (H2MPMT+Cl-, C5H7N2SCl) and 2-mercapto-benzoic acid (H(2)MBA, C7H6O2S), of the formulae [Ph3Sn(MPMT)] (1), [Me2Sn(MPMT)(2)] (2), {[(n-Bu)(2)Sn(MBA)](2)}(n) (3), already reported in the literature, and {[Me2Sn(MBA)](2)}n (4), with a different structure to the one already reported, have been used to study their influence upon the catalytic peroxidation of linoleic acid by the enzyme lipoxygenase (LOX). The IC50 values found lie in the range 20-30 mu M. The crystal structure of 4 was determined by X-ray diffraction at room temperature (293(2) K). The structure of 4 is polymeric and it consists of {[Me2Sn(MBA)](2)} dimeric building blocks in contrast to the complex of the same formula reported earlier which has a hexameric cyclic structure. Intermolecular Sn-O bonding interactions between these units in 4 lead to the formation of infinite chains with helical conformations. In addition the crystal structure of 3, previously reported with R = 9.9%, was now reduced to R = 6.1%. Comparison with the already reported hexanuclear macrocycle complexes {[(n-Bu)(2)Sn(MBA)](6)} (5) and {[Me2Sn(MBA)](6) H2O} (6) to the helical polymeric 3 and 4 was made. DFT calculations performed for the hexameric complex 6 and helical polymeric complex 4 have shown that the energy (Delta E) difference between the two polymeric and hexanuclear conformers is only 1.65 Kcal/mol. Finally, the crystal structure of complex 2, previously solved in the orthorhombic Cmc2(1) space group, was now solved in the monoclinic P2(1)/n space group. (C) 2008 Elsevier Ltd. All rights reserved. Polyhedron

Megalithic potteries collected from Adhichanallur, Tamilnadu, India ( Lat. 8 44'N; Long. 77. 42'E) have been subjected to various spectroscopic and rock magnetic studies. The type of clay, their origin, level of structural deformation due to firing, firing temperature and atmospheric condition followed during making the potteries are analyzed. The potteries were subjected to Mossbauer and X- ray diffraction studies to analyze the iron phases in them. It is found that the samples were made of local clay ( red clay), fired above 600. C under open atmospheric and/ or reduced atmospheric conditions and air has been allowed during cooling. The Mossbauer spectra reveal the presence of Fe(3+), Fe(2+) and iron oxides of hematite and magnetite. The firing temperature and firing conditions established from Mossbauer studies are similar to the observation made from FT- IR studies. The magnetic mineral types, the mass fractions and the domain states of the constituent magnetic grains were elucidated from a range of rock magnetic measurements including variation of susceptibility with low field, frequency and temperature, hysteresis parameters and isothermal remanence acquisition data. The magnetic mineralogy of most pottery samples was dominated by magnetite/( titano) magnetite, while magnetic grain size spectrum varies from very fine ( super paramagnetic) to fine ( stable single domain, pseudo single domain). The reversible thermo magnetic behavior reflects no mineralogical transformations during reheating and all the samples show same Curie temperature 580C due to magnetite. From the above information it is demonstrated that these samples are suitable for determining the reliable ancient geomagnetic field intensity values existed during that period. Hyperfine Interactions

Organotin(IV) complexes with the formulas [(C(6)H(5))(3)Sn(mbzt)] (1), [(C(6)H(5))(3)Sn(cmbzt)] (3), and [(C(6)H(5))(2)Sn(cmbzt)(2)] (4) (Hmbzt = 2-mercaptobenzothiazole and Hcmbzt = 5-chloro-2-mercaptobenzothiazole) have been synthesized and characterized by elemental analysis; FT-IR, Raman, (1)H, (13)C, and (119)Sn NMR, and Mossbauer spectroscopic techniques; and X-ray crystallography at various temperatures. The crystal structures of complexes 1, 3, and 4 were determined by X-ray diffraction at room temperature [295(1) or 293(2) K]. The complexes [(C(6)H(5))(3)Sn(mbzo)] (2) and [(n-C(4)H(9))(2)Sn(cmbzt)(2)] (5) (Hmbzo = 2-mercaptobenzoxazole) were synthesized by new improved methods, and their structures were determined at low temperature [100(1) K] and compared to those solved at room temperature. Comparison with {(CH(3))(2)Sn(cmbzt)(2)]} (6), already reported, was also attempted. The influence of temperature on the geometry of the complexes is discussed. In the cases of complexes 1-3, three carbon atoms from phenyl groups and one sulfur atom and one nitrogen atom from thione ligands form a tetrahedrally distorted trigonal-bipyramidal geometry around the five-coordinate tin(IV) ion. In complexes 4-6, two carbon atoms from aryl groups and two sulfur atoms and two nitrogen atoms from thione ligands form a distorted tetrahedral geometry, tending toward octahedral, around the six-coordinate tin(IV) ions, with trans-C(2), cis-N(2), and cis-S(2) configurations. Although the C-Sn and S-Sn bond distances are found to be constant in compounds 1-6, their N-Sn bond lengths vary significantly (from 2.635 to 3.078 angstrom), with the longer distances found in the cases of five-coordinate complexes 1-3. Inorg Chem

The synthesis and detailed characterization of a few samples of the compound RbxMn[Fe(CN)(6)](y)center dot zH(2)O are described. The composition of the materials significantly depends on the applied preparative conditions. Analysis of spectroscopic results (FTIR, Raman, Fe-57 Mossbauer, XPS) and X-ray powder-diffraction data yielded a further assessment of the difference in structural features in terms of the amount of Fe(CN)6 vacancies and the associated number of water molecules. The characteristic individual magnetic behavior, as well as the metal-to-metal charge-transfer capabilities of the various samples, could be related to significant changes within the structures that appear to be associated with the synthetic method used.

The complex [(C6H5)(2)SnCl(HMNA)] (1) where H(2)MNA is thioamide 2-mercapto-nicotinic acid has been synthesized by reacting a methanolic solution of di-chloro-di-phenyltin(IV) Ph2SnCl2 with an aqueous solution of 2-mercapto-nicotinic acid, containing twofold amount of potassium hydroxide. The Sn/ligand molar ratio is 2:1. The complex was characterized by elemental analysis, FT-IR and Mossbauer spectroscopic techniques. In addition the crystal structure of the molecule was determined by all X-ray diffraction at 293(2) K. C18H14ClNO2SSn is monoclinic, space group P2(1)/n, a = 15.089(3) angstrom, b = 15.846(3) angstrom, c = 16.691(3) angstrom, beta = 105.57(3)degrees, Z = 8. The ligand coordinates to the metal center through the exocyclic sulfur and the heterocyclic nitrogen atoms, forming a four membered ring. The coordination sphere around the tin(IV) ion is completed with two carbon atoms from the two phenyl groups and one chlorine atom. The geometry around the tin atom can be described either as trigonal bipyramidal or tetragonal pyramidal. Finally, the influence of the complex [(C6H5)(2)SnCl(HMNA)] (1) upon the catalytic peroxidation of linoleic acid to hydroperoxylinoleic acid by the enzyme lipoxygenase (LOX) was also kinetically and theoretically studied and the results compared with the ones of the corresponding binuclear complex [(C6H5)(3)Sn(MNA)Sn(C6H5)(3) (acetone)] (2) reported in the literature. (c) 2005 Elsevier B.V. All rights reserved. Journal of Organometallic Chemistry

Formation and magnetic properties of the interstitial Nd-3(Fe,Ti)(29)-type nitrides were investigated for Nd-3(Fe1-xCox)(27.7)Ti-1.3 over the concentration range 0 < x less than or equal to 0.4. The decomposition temperature T-d decreases with increasing Co content x. The relative lattice expansion upon nitrogenation is 4.6-4.9% indicating 3.5-3.7 N-atoms per formula unit. Upon nitrogenation the Curie temperature values increase with Co, but the increase rate is slower compared to that of the parent compounds. For x = 0.1, 0.2 a complex magnetic anisotropy is observed, whereas, for x = 0.3 and 0.4 the compounds present uniaxial anisotropy with an easy magnetisation direction along the [40-2] direction. The increase of the average hyperfine field by substituting Co for Fe in Nd-3(Fe1-xCox)(27.7)Ti1.3Ny is rather small and the position of the maximum (x = 0.1) at room temperature is closer to Fe than for the parent compounds (at least x = 0.4). (C) 2003 Elsevier B.V. All rights reserved. Journal of Magnetism and Magnetic Materials

Novel clay-carbon tube composites were synthesized by catalytic decomposition of acetylene over iron-catalyst centers supported on montmorillonite surfaces by ion-exchange. TEM and SEM micrographs show the growth of carbon tubes rooted to the clay surfaces, while the iron-nanoparticles (which catalyze the formation of carbon-nanotubes) are detected and characterized by Mossbauer spectroscopy, mainly as ferromagnetic cementite (Fe3C). In the hybrid materials the clay retains its exchange properties making possible the preparation of clay-carbon nanotube derivatives that are valuable for various technological applications. (C) 2002 Elsevier Science Ltd. All rights reserved. Carbon