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The synthesis and characterization of three new calix[4]arene ligands bearing two pendant acylhydrazone arms and some of their Cu2+ complexes, namely [Cu(L1‐2H)(MeOH)] (3), [Cu(L1'‐H)(Cl)(2‐hydroxy‐1‐naphthaldehyde)] (4), [Cu2(L2‐2H)2] (5) and [Cu4(L3‐2H)2(OH)2(ClO4)2] (6) are described. The ligands are obtained by simple imine condensation reactions between calix[4]arene‐1,3‐bis‐acyl‐hydrazides and the corresponding carbaldehydes. The Cu2+ ions are always situated in 5‐membered chelate rings, either in a deprotonated −O−CR=N−N=CHR (enolate) or a neutral O=CR−NH−N=CHR (keto) form. In 3 and 4 a 5‐membered chelate ring is formed through interaction of the Cu2+ ion with the naphtholato group. Additional MeOH, chlorido or naphthaldehyde ligands complete the planar (3) or square pyramidal (4) coordination spheres. The thiophenes in 5 do not interact with the Cu2+ ions and dimerization of [CuL] entities occurs to produce centrosymmetric 2 : 2 complexes with four‐coordinated Cu2+ ions. In 6, two dinuclear [Cu2(L3‐2H)(OH)] subunits are connected by μ1,3‐bridging ClO4− ions. The magnetic properties of polycrystalline samples of 5 and 6 were studied by variable temperature magnetic susceptibility measurements. The χ′′(T) vs T plots indicate antiferromagnetic exchange interactions. The exchange interactions in 6 (J=−4.8 cm−1) were found to be stronger than in 5 (J=−0.54 cm−1). This is also supported by broken symmetry DFT calculations. [ABSTRACT FROM AUTHOR]

Iron thin films were deposited on glass substrates using RF magnetron sputtering and their optimal deposition conditions were determined. The structure properties were analyzed using x-ray diffraction (XRD) and their magnetic hysteresis loops were obtained by Vibrating Sample Magnetometer (VSM) at room temperature. In this situation, the magnetic field is either parallel or perpendicular to the substrate plane. The main contribution of this work is to characterize the thin layers and present a mathematical model that can get best fit of the characteristics B(H). By using Preisach model, good agreement was obtained between theoretical and experimental results in both cases.

Temperature-dependent luminescence spectra for a series of palladium(II) and platinum(II) complexes with thiocyanate, halide, and dithiocarbamate ligands are presented. All complexes showbroad d-d luminescence. Crystal structures are reported for [(n-[Bu.sub.4]N).sub.2][Pt[(SCN).sub.4]] and [(n-[Bu.sub.4]N).sub.2][Pd[(SCN).sub.4]] at 150 and 250 K, for the palladium(II) dimethyldithiocarbamate (MeDTC) complex [Pd[(MeDTC).sub.2]] at 150 and 300 K, and for its platinum(II) analog at 100 and 300 K. The structures of [(n-[Bu.sub.4]N).sub.2][Pt[(SCN).sub.4]], [(n-[Bu.sub.4]N).sub.2][Pd[(SCN).sub.4]], and [Pt[(MeDTC).sub.2]] show similar volume increases with temperature. In contrast, the luminescence band maxima of palladium(II) and platinum(II) complexes have opposite shifts with increasing temperature. [(n-[Bu.sub.4]N).sub.2][Pd[(SCN).sub.4]] shows a shift of -2.0 [cm.sup.-1]/K and [Pd[(MeDTC).sub.2] ] a shift of -1.1 [cm.sup.-1]/K, while both platinum(II) complexes have a positive shift of +1.6 [cm.sup.-1]/K. Calculated luminescence spectra with adjustable parameters reproduce the experimental spectra. The variation of their parameters with temperature shows the origin of different trends. Temperature-dependent luminescence spectra of [[Pd[(SCN).sub.4]].sup.2-] and [[Pt[(SCN).sub.4]].sup.2-] in polymer films of polyvinyl alcohol were measured. No clearcut shifts of maxima were observed for either compound, and their spectra are broader due to the disordered environment. Key words: palladium(II) complexes, platinum(II) complexes, crystal structures, temperature-dependent luminescence spectroscopy, calculated luminescence spectra. Des spectres de luminescence a temperature variable sont presentes pour une serie de complexes de platine(II) et de palladium(II) ayant des ligands thiocyanates et halogenes, ainsi que des ligands dithiocarbamate chelatants. Tous les complexes presentes montrent de larges bandes de transition d-d en luminescence. Les structures cristallines a 150 et 250 K sont presentees pour les complexes [(n-[Bu.sub.4]N).sub.2][Pt[(SCN).sub.4]] et [(n-[Bu.sub.4]N).sub.2][Pd[(SCN).sub.4]], a 150 et 300 K pour le complexe de palladium(II) de dimethyldithiocarbamate (MeDTC) et a 100 et 300 K pour l'analogue de platine(II). Les structures de [(n- [Bu.sub.4]N).sub.2][Pt[(SCN).sub.4]], [(n-[Bu.sub.4]N).sub.2][Pd[(SCN).sub.4]], [Pd[(MeDTC).sub.2]] et [Pt[(MeDTC).sub.2]] montrent une augmentation similaire du volume de la maille cristalline avec l'augmentation de temperature. Malgre leurs ressemblances structurales, les complexes de platine(II) et palladium(II) presentent cependant des decalages opposes des maxima des spectres de luminescence en fonction de la temperature. En effet, le complexe [(n-[Bu.sub.4]N).sub.2][Pd[(SCN).sub.4]] montre un decalage vers les faibles energies de -2.0 [cm.sup.-1]/K et le complexe [Pd[(MeDTC).sub.2]] un decalage correspondant de -1.1 [cm.sup.-1]/K, tandis que les deux complexes de platine(II) montrent un decalage des maxima vers les energies plus elevees de +1.6 [cm.sup.-1]/K. Des spectres de luminescence calcules a l'aide de parametres ajustables ont permis de reproduire les spectres experimentaux. La variation de ces parametres ajustables permet d'expliquer l'origine des tendances differentes pour le decalage des maxima. Des spectres de luminescence a temperature variable ont aussi ete mesures pour des complexes de [[Pd[(SCN).sub.4]].sup.2-] et de [[Pt[(SCN).sub.4]].sup.2-] dissout dans des films de polymeres de polyvinyl alcohol. Dans ces spectres, aucun decalage du maxima n'a ete observe pour les complexes, et les spectres sont beaucoup plus larges dus a l'environnement desordonne dans lequel les complexes se trouvent. Mots-cles : complexes de palladium(II), complexes de platine(II), structures cristallines, spectroscopie de luminescence a temperature variable, spectres de luminescence calcules., Introduction Square-planar complexes of platinum(II) and palladium(II) with a [d.sup.8] electron configuration have interesting luminescence properties (1-4) highly influenced by their environment. (5-8) Significant effects of temperature or pressure on [...]

The electronic structure of a trigonally distorted vanadium(III) complex, [V(urea)8](CIO4)3 and its deuterated analogue, [V(urea-d4)6](CIO4)3 is investigated with Raman, luminescence, and high-frequency high-field electron paramagnetic resonance spectroscopies. A broad electronic Raman transition is observed at around 1400 cm(super -1) and attributed to a transition to the (super 3)E (D3) component of the (super 3)T(sub 1g) (O(sub n)) ground state.

The synthesis, structure, and magnetism of two manganese(II) tetranuclear complexes, {Mn4(thiaS)2] and [Mn4(thiaSO)2] resulting from P-tert-butylthiacalix[4]arene (thiaS) and p-tert-butylsultinylthiacalix[4]arena(thiaSo) are described. Both clusters confirm the high coordination ability of thiacalixarene macrocycles.

The biradical L derived by linking two nitronyl nitroxide radicals in the 5 and 5' substitution positions of a 2,2'-bipyridine core produce a one-dimensional chain compound. The fusion, crystal arrangement, and magnetic components of this 1D compound are explained.

Thiocyanatonickel(II) compounds with composition {[(As[Ph.sub.4]).sub.2][Ni[(NCS).sub.4]]} 1, {(Cat)[Ni[(NCS).sub.4]]} 2, {(As[Ph.sub.4]).sub.4][[Ni.sub.2][(NCS).sub.8]] } 3, {[(Cat).sub.2] [[Ni.sub.2][(NCS).sub.8]]*2[CH.sub.3][NO.sub.2]} 4, and {[([Et.sub.4]N).sub.4][Ni[(NCS).sub.6]]} 5 ([Cat.sup.2+] = [(p-xylylenebis(triphenyphosphonium)).sup.2+]) were prepared. The crystal structures of compounds 1, 3, and 4 were determined. Compound 1 crystallizes in the monoclinic C2/c space group with a = 22.761(2) [Angstrom], b = 15.055(1) [Angstrom], c = 15.054(1) [Angstrom], [beta] = 108.915(1)[degrees], V = 4879.9(6) [Angstrom].sup.3], and Z = 4. Compound 3 crystallizes in the triclinic P1 space group with a = 11.2183(6) [Angstrom], b = 14.2551(8) [Angstrom], c = 16.629(1) [Angstrom], [alpha] = 79.326(1)[degrees], [beta] = 73.605(1)[degrees], [gamma] = 75.496(1)[degrees], V = 2451.0(2) [Angstrom].sup.3], Z = 2. Compound 4 crystallizes in the monoclinic [P2.sub.1]/n space group with a = 13.1148(9) [Angstrom], b = 27.128(2) [Angstrom], c = 14.882(1) [Angstrom], [beta] = 114.056(2)[degrees], V = 4834.8(6) [[Angstrom].sup.3], Z = 4. The magnetic properties of compounds 1-4 were studied over the 2-300 K temperature range. Compounds 1 and 2 with monometallic [Ni[(NCS).sub.4]].sup.2-] complex units have similar magnetic properties, in agreement with nickel(II) ions in pseudo-tetrahedral environments. Compounds 3 and 4 with bimetallic [[[Ni.sub.2][(NCS).sub.8]].sup.4-] complex units exhibit magnetic properties, which are indicative of Ni(II)-Ni(II) ferromagnetic interactions with zero-field splitting effects caused by the pseudo-square-pyramidal or pseudo-trigonal-bipyramidal coordination environments of the nickel(II) ion in compounds 3 and 4, respectively. The structures and magnetic results for all compounds are correlated with NIR--UV--vis absorption spectra. Key words: nickel(II) thiocyanato complexes, crystal structures, paramagnetism, molecular magnetism, exchange coupling, absorption spectroscopy.

Research has been conducted on the gadolinium(III) and europium(III) complexes with imino nitroxide or nitronyl radicals. The synthesis and crystal structures of these complexes have been investigated and their electronic structure has been studied via optical spectroscopy measurements in order to understand the effects defining their magnetism.

The synthesis, structure, and magnetic pproperties of three each of lanthanum(III) and gadolinium(III) complexes of nitronyl nitroxide radicals carrying substitutions of either 2-benzimidazolyl or the 2-(6-methylbenzimidazolyl) is presented. Results point out that the antiferromagnetic gadolinium(sup)III-radical interactions are common to all the gadolinium(III) complexes. The magnetic interaction is attributed to structural and ligand effects.

Research has been conducted on the sandwich litetium(III) bisphthalocyanine. The synthesis of this compound substituted with the hexylthio groups has been carried out and the results indicate that this compound is soluble in the organic solvents and has been characterized via the elemental analysis, IR, NMR and UV-vis spectroscopy and mass spectroscopy.