Electrochemical properties of Cu4[PhN3C6H4N3(H)Ph]4(��-O)2, a tetranuclear Copper(II) complex with 1-phenyltriazenido-2-phenyltriazene-benzene as ligand

Bis-(��2-oxo)-tetrakis{[1-feniltriazene-1,3-diil)-2-(phenyltriazenil)benzene copper(II) is a tetranuclear complex which shows four Cu(II) ions coordinated by four 1,2-bis(phenyltriazene)benzene bridged ligands, with one diazoaminic deprotonated chain, and two O2- ligands. The complex reduces at E1/2 = -0.95 V vs Fc+/Fc, a two electrons process. Cyclic voltammetric and spectroelectrochemical studies showed a reversible process. When immobilized on carbon paste electrode, the complex electrocatalyses the reduction of O2 dissolved on aqueous solution at -0.3 V vs SCE potential. The obtained current shows linearity with O2 concentration.

Comparison of the dehydration kinetics of solid state compounds of 2-methoxybenzylidenepyruvate with some divalent metal ions

Divalent metal complexes of ligand 2-methoxybenzylidenepyruvate with Fe, Co, Ni, Cu and Zn as well as sodium salt were synthesized and investigated in the solid state. TG curves of these compounds were obtained with masses sample of 1 and 5mg under nitrogen atmosphere. Different heating rates were used to characterize and study these compounds from the kinetic point of view. The activation energy and pre-exponential factor were obtained applying the Wall-Flynn-Ozawa method to the TG curves. The obtained data were evaluated and the values of activation energy (Ea / kJ mol-1) was plotted in function of the conversion degree (α). The results show that due to mass sample, different activation energies were obtained. The results are discussed mainly taking into account the linear dependence between the activation energy and the pre exponential factor, where was verified the effect of kinetic compensation (KCE) and possible linear relations between the dehydrations steps of these compounds.

Synthesis, characterization and thermal behaviour of solid 2-methoxycinnamylidenepyruvate of some bivalent metal ions in CO2 and N2 atmospheres

Solid State M-2-MeO-CP compounds, where M stands for bivalent metals (Mn, Fe, Co, Ni, Cu and Zn) and 2-MeO-CP is 2-methoxycinnamylidenepyruvate, were synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), elemental analysis and complexometry were used to establish the stoichiometry and to study the thermal behaviour of these compounds in CO2 and N2 atmospheres. The results were consistent with the general formula: M(L)2∙H2O. In both atmospheres (CO2, N2) the thermal decomposition occurs in consecutive steps which are characteristic of each compound. For CO2 atmosphere the final residues were: Mn3O4, Fe3O4, Co3O4, NiO, Cu2O and ZnO, while under N2 atmosphere the thermal decomposition is still observed at 1000 �� C.

Efeito de n��veis de ��gua, coberturas do solo e condi����es ambientais na temperatura do solo e no cultivo de morangueiro em ambiente protegido e a c��u aberto

A temperatura do solo �� um importante par��metro no cultivo do morangueiro, pois interfere no desenvolvimento vegetativo, na sanidade e na produ����o. O objetivo do presente trabalho foi avaliar o efeito de diferentes n��veis de ��gua, coberturas de canteiro em campo aberto e em ambiente protegido, na temperatura m��xima do solo no cultivo do morangueiro. Foram realizados dois experimentos: um em cultivo protegido e outro a campo aberto, em Atibaia - SP, em esquema fatorial 2 x 3 (coberturas do solo e n��veis de irriga����o), em blocos ao acaso, com cinco repeti����es. As coberturas de solo utilizadas foram filmes de polietileno preto e transparente. A irriga����o localizada foi aplicada por gotejo sempre que o potencial de ��gua no solo atingisse -0,010 (N1), -0,035 (N2) e -0,070 (N3) MPa, em tensi��metros instalados a 10 cm de profundidade. A temperatura do solo foi avaliada por term��grafos, sendo os sensores instalados a 5 cm de profundidade. Houve influ��ncia do ambiente de cultivo, da cobertura do solo e dos n��veis de irriga����o na temperatura m��xima do solo. A temperatura do solo sob diferentes coberturas dependeu n��o somente das caracter��sticas f��sicas do pl��stico, como tamb��m da forma de instala����o no canteiro. A temperatura m��xima do solo aumentou com a diminui����o do potencial da ��gua no solo, no momento da irriga����o.

Influ��ncia dos ��ons Mg, Ca, Fe, Cu e Zn sobre a tens��o superficial est��tica de solu����es contendo surfatante

O objetivo do estudo foi avaliar a influ��ncia da presen��a de cinco ��ons em uma calda de pulveriza����o contendo o surfatante Aterbane. A tens��o superficial foi analisada por meio da medi����o da massa de um conjunto de 25 gotas, com quatro repeti����es constituindo um tratamento. O trabalho foi dividido em duas etapas. Na primeira, os tratamentos foram combinados em esquema fatorial 9x5x2, sendo nove concentra����es do surfatante Aterbane (0,01; 0,025; 0,05; 0,1; 0,2; 0,5; 1; 2; e 3%), cinco ��ons (Mg++, Ca++, Fe+++, Cu+++ e Zn+++) e duas concentra����es desses elementos (10 e 100 ppm). Na segunda etapa, os tratamentos foram combinados em esquema fatorial 5x5x1, utilizandose os mesmos cinco elementos (Mg++, Ca++, Fe+++, Cu+++ e Zn+++), em cinco concentra����es (1, 5, 20, 50 e 200 ppm), com apenas uma concentra����o do surfatante Aterbane (0,025%). Outros nove tratamentos permitiram avaliar as tens��es superficiais das concentra����es do surfatante (0,01; 0,025; 0,05; 0,1; 0,2; 0,5; 1; 2; e 3%) sem a adi����o dos ��ons. Os resultados mostraram que houve interfer��ncia dos ��ons sobre as solu����es, j�� que, com exce����o do Fe+++ (na concentra����o de 10 e 100 ppm) e do Cu+++ (na concentra����o de 100 ppm), todos os ��ons reduziram a tens��o m��nima alcan��ada e aumentaram a efici��ncia do surfatante, implicando benef��cios �� a����o do surfatante e sobre as caracter��sticas de poss��veis solu����es de aplica����o. Todos os ��ons avaliados promoveram redu����es nas tens��es superficiais de solu����es do surfatante na concentra����o de 0,025%.

[Balladi nro 2 F-duuri]

Soitinnus: piano.

[Scherzo nro 2 b-molli]

Soitinnus: piano.

Tetrathiafulvalene and 2,2'-Bipyridine: Bridging both Worlds in the Pursuit of Novel Molecular Materials

The preparation and characterization of two families of building blocks for molecule-based magnetic and conducting materials are described in three projects. In the first project the synthesis and characterization of three bis-imine ligands LI - L3 is reported. Coordination of LI to a series of metal salts afforded the five novel coordination complexes Sn(L4)C4 (I), [Mn(L4)(u-CI)(CI)(EtOH)h (II), [CU(L4)(u-sal) h(CI04)2 (sal = salicylaldehyde anion) (III), [Fe(Ls)2]CI (IV) and [Fe(LI)h(u-O) (V). All complexes have been structurally and magnetically characterized. X-ray diffraction studies revealed that, upon coordination to Lewis acidic metal salts, the imine bonds of LI are susceptible to nucleophilic attack. As a consequence, the coordination complexes (I) - (IV) contain either the cyclised ligand L4 or hydrolysed ligand Ls. In contrast, the dimeric Fe3+ complex (V) comprises two intact ligand LI molecules. In. this complex, the ligand chelates two Fe(III) centres in a bis-bidentate manner through the lone pairs of a phenoxy oxygen and an imine nitrogen atom. Magnetic studies of complexes (II-V) indicate that the dominant interactions between neighbouring metal centres in all of the complexes are antiferromagnetic. In the second project the synthesis and characterization two families of TTF donors, namely the cyano aryl compounds (VI) - (XI) and the his-aryl TTF derivatives (XII) - (XIV) are reported. The crystal structures of compounds (VI), (VII), (IX) and (XII) exhibit regular stacks comprising of neutral donors. The UV -Vis spectra of compounds (VI) - (XIV) present an leT band, indicative of the transfer of electron density from the TTF donors to the aryl acceptor molecules. Chemical oxidation of donors (VI), (VII), (IX) and (XII) with iodine afforded a series of CT salts that where possible have been characterized by single crystal X -ray diffraction. Structural studies showed that the radical cations in these salts are organized in stacks comprising of dimers of oxidized TTF donors. All four salts behave as semiconductors, displaying room temperature conductivities ranging from 1.852 x 10-7 to 9.620 X 10-3 Scm-I. A second series of CT salts were successfully prepared via the technique of electrocrystallization. Following this methodology, single crystals of two CT salts were obtained. The single crystal X-ray structures of both salts are isostructural, displaying stacks formed by trimers of oxidized donors. Variable temperature conductivity measurements carried out on this series of CT salts reveal they also are semiconductors with conductivities ranging from 2.94 x 10-7 to 1.960 X 10-3 S em-I at room temperature. In the third project the synthesis and characterization of a series of MII(hfac)2 coordination complexes of donor ligand (XII) where M2+ = Co2+, Cu2+, Ni2+ and Zn2+ are reported. These complexes crystallize in a head-to-tail arrangement of TTF donor and bipyridine moieties, placing the metal centres and hfac ligands are located outside the stacks. Magnetic studies of the complexes (XV) - (XVIII) indicate that the bulky hfac ligands prevent neighbouring metal centres from assembling in close proximity, and thus they are magnetically isolated.

Estudio respirom��trico de Lactobacillus casei ATCC 393 en presencia de iones Cu (II) y Zn (II)

Tesis (Maestr��a en Ciencias con Especialidad en Microbiolog��a Industrial) UANL

Caracterizaci��n electroqu��mica de la inserci��n de litio en MnNb2O6 (M= Mn, Co, Ni, Cu, Zn, Cd) y en Li3X2NbO6 (X= Mn, Co, Ni)

Tesis (Maestr��a en Ciencias con Especialidad en Ingenier��a Cer��mica) UANL

Inserci��n electroqu��mica de litio en compuestos de f��rmula general MWO4 (M= Co, Cu, Mn, Ni, Zn, y Zn) preparados por dos rutas de s��ntesis [por] Sagrario Mart��nez Montemayor

Tesis (Maestr��a en Ciencias con Especialidad en Ingenier��a Cer��mica) U.A.N.L.

Estudio de adhesibilidad entre una aleaci��n de aluminio A319.0 y una camisa de aluminio base Al-Si-Cu-MG. para aplicaciones automotrices

Teis ( Maestro en Ciencias de Ingenier��a Mec��nica con Especialidad en materiales) U.A.N.L.

Pel��culas delgadas de Cu(In,Al)Se?(CIAS) por m��todos no t��xicos para aplicaci��n en celdas solares.

Tesis (Maestr��a en Ciencias de la Ingenier��a Mec��nica con Especialidad en Materiales) UANL, 2011.

Eliminaci��n fotocatal��tica de tricloroetileno empleando como catalizador TiO? dopado con Cu (II).

Tesis (Maestr��a en Ciencias con Orientaci��n en Procesos Sustentables) UANL, 2013.

Efecto de estr��s inducido con NaCI, Cu��? y Fe��? en biomasa, timol, carvacrol y prolina en or��gano mexicano (lippia graveolens H.B.K.).

Tesis (Doctorado en Ciencias con Acentuaci��n en Qu��mica de Productos Naturales) UANL, 2012.