Síntese e caracterização de complexos de Co(II) e Ni(II) com l-dopa, carbidopa e benzimidazol

Were synthesized in this work in the following aqueous solution coordination compounds: [Ni(LDP)(H2O)2Cl2].2H2O, [Co(LDP)Cl2].3H2O, [Ni(CDP)Cl2].4H2O, [Co(CDP)Cl2].4H2O, [Ni(BDZ)2Cl2].4H2O and [Co(BDZ)2Cl2(H2O)2]. These complexes were synthesized by stoichiometric addition of the binder in the respective metal chloride solutions. Precipitation occurred after drying the solvent at room temperature. The characterization and proposed structures were made using conventional analysis methods such as elemental analysis (CHN), absorption spectroscopy in the infrared Fourier transform spectroscopy (FTIR), X-ray diffraction by the powder method and Technical thermoanalytical TG / DTG (thermogravimetry / derivative thermogravimetry) and DSC (differential scanning calorimetry). These techniques provided information on dehydration, coordination modes, thermal performance, composition and structure of the synthesized compounds. The results of the TG curve, it was possible to establish the general formula of each compound synthesized. The analysis of X-ray diffraction was observed that four of the synthesized complex crystal structure which does not exhibit the complex was obtained from Ldopa and carbidopa and the complex obtained from benzimidazole was obtained crystal structures. The observations of the spectra in the infrared region suggested a monodentate ligand coordination to metal centers through its amine group for all complexes. The TG-DTG and DSC curves provide important information and on the behavior and thermal decomposition of the synthesized compounds. The molar conductivity data indicated that the solutions of the complexes formed behave as a nonelectrolyte, which implies that chlorine is coordinated to the central atom in the complex.

Síntese e caracterização de complexos de Co(II) e Ni(II) com l-dopa, carbidopa e benzimidazol

Were synthesized in this work in the following aqueous solution coordination compounds: [Ni(LDP)(H2O)2Cl2].2H2O, [Co(LDP)Cl2].3H2O, [Ni(CDP)Cl2].4H2O, [Co(CDP)Cl2].4H2O, [Ni(BDZ)2Cl2].4H2O and [Co(BDZ)2Cl2(H2O)2]. These complexes were synthesized by stoichiometric addition of the binder in the respective metal chloride solutions. Precipitation occurred after drying the solvent at room temperature. The characterization and proposed structures were made using conventional analysis methods such as elemental analysis (CHN), absorption spectroscopy in the infrared Fourier transform spectroscopy (FTIR), X-ray diffraction by the powder method and Technical thermoanalytical TG / DTG (thermogravimetry / derivative thermogravimetry) and DSC (differential scanning calorimetry). These techniques provided information on dehydration, coordination modes, thermal performance, composition and structure of the synthesized compounds. The results of the TG curve, it was possible to establish the general formula of each compound synthesized. The analysis of X-ray diffraction was observed that four of the synthesized complex crystal structure which does not exhibit the complex was obtained from Ldopa and carbidopa and the complex obtained from benzimidazole was obtained crystal structures. The observations of the spectra in the infrared region suggested a monodentate ligand coordination to metal centers through its amine group for all complexes. The TG-DTG and DSC curves provide important information and on the behavior and thermal decomposition of the synthesized compounds. The molar conductivity data indicated that the solutions of the complexes formed behave as a nonelectrolyte, which implies that chlorine is coordinated to the central atom in the complex.

O uso pedagógico de uma seqüência didática para a aquisição de algumas idéias relacionadas ao conceito de números complexos

The aim of the present work is to contribute to the teaching-learning process in Mathematics through an alternative which tries to motivate the student so that he/she will learn the basic concepts of Complex Numbers and realize that they are not pointless. Therefore, this work s general objective is to construct a didactic sequence which contains structured activities that intends to build up, in each student s thought, the concept of Complex Numbers. The didactic sequence is initially based on a review of the main historical aspects which begot the construction of those numbers. Based on these aspects, and the theories of Richard Skemp, was elaborated a sequence of structured activities linked with Maths history, having the solution of quadratic equations as a main starting point. This should make learning more accessible, because this concept permeates the students previous work and, thus, they should be more familiar with it. The methodological intervention began with the application of that sequence of activities with grade students in public schools who did not yet know the concept of Complex Numbers. It was performed in three phases: a draft study, a draft study II and the final study. Each phase was applied in a different institution, where the classes were randomly divided into groups and each group would discuss and write down the concepts they had developed about Complex Numbers. We also use of another instrument of analysis which consisted of a recorded interview of a semi-structured type, trying to find out the ways the students thought in order to construct their own concepts, i.e. the solutions of the previous activity. Their ideas about Complex Numbers were categorized according to their similarities and then analyzed. The results of the analysis show that the concepts constructed by the students were pertinent and that they complemented each other this supports the conclusion that the use of structured activities is an efficient alternative for the teaching of mathematics

Obtenção de dispersões de complexos polieletrolíticos à base de quitosana e poli(ácido metacrílico) e análise de adsorção de albumina bovina sérica

Dispersions composed of polyelectrolyte complexes based on chitosan and poly(methacrylic acid), PMAA, were obtained by the dropping method and template polymerization. The effect of molecular weight of PMAA and ionic strength on the formation of chitosan/poly(methacrylic acid), CS/PMAA, complexes was evaluated using the dropping method. The increase in molecular weight of PMAA inhibited the formation of insoluble complexes, while the increase in ionic strength first favored the formation of the complex followed by inhibiting it at higher concentrations. The polyelectrolyte complexation was strongly dependent on macromolecular dimensions, both in terms of molecular weight and of coil expansion/contraction driven by polyelectrolyte effect. The resultant particles from dropping method and template polymerization were characterized as having regions with different charge densities: chitosan predominating in the core and poly(methacrylic acid) at the surface, the particles being negatively charged, as a consequence. Albumin was adsorbed on templatepolymerized CS/PMAA complexes (after crosslinking with glutardialdehyde) and pH was controlled in order to obtain two conditions: (i) adsorption of positively charged albumin, and (ii) adsorption of albumin at its isoelectric point. Adsorption isotherms and zeta potential measurements showed that albumin adsorption was controlled by hydrogen bonding/van der Waals interactions and that brushlike structures may enhance adsorption of albumin on these particles

Estudo de complexos de ferro e de cobre com a base de Shiff 3-Meosalen e ligantes de relevância biológica

The goal set for this work was to synthesize and to characterize new iron and copper complexes with the Schiff base 3-MeOsalen and ligands of biological relevance, whose formulas are [Fe(3-MeOsalen)NO2], [Fe(3-MeOsalen)(etil2-dtc)], [Fe(3-MeOsalen)NO] and Na[Cu(3-MeOsalen)NO2]. The compounds were characterized by vibrational spectroscopy in the infrared region (IV) and Electronic spectroscopy in the ultraviolet and visible region (Uv-Vis). From the analysis of infrared spectra, they proved to formation of precursor complexes, as evidenced by changes in the vibrationals frequencies ν(C=N) e ν(C-O) and the emergence of vibrationals modes metal-oxygen and metal-nitrogen. For nitro complexes of iron and copper were observed ν(NO2)ass around 1300 cm-1 e ν(NO2)sim in 1271 cm-1 , indicating that the coordination is done via the nitrogen atom. The complex spectrum [Fe(3-MeOsalen)(etil2-dtc)] exhibited two bands, the ν(C-NR2) in 1508 cm-1 e ν(C-S) in 997 cm-1 , the relevant vibrational modes of coordinating ligand in the bidentate form. For the complex [Fe(3-MeOsalen)NO] was observed a new intense band in 1670 cm-1 related to the ν(NO). With the electronic spectra, the formation of complexes was evidenced by shifts of bands intraligands transitions and the emergence of new bands such as LMCT (p Cl-  d* Fe3+) in [Fe(3-MeOsalen)Cl] and the d-d in [Cu(3-MeOsalen)H2O]. As for the [Fe(3-MeOsalen)NO2] has highlighted the absence of LMCT band present in the precursor complex as for the [Cu(3-MeOsalen)NO2] found that the displacement of the band hipsocrômico d-d on 28 nm. The electronic spectrum of [Fe(3-MeOsalen)(etil2-dtc)] presented LMCT band shifts and changes in intraligantes transitions. With regard to [Fe(3-MeOsalen)NO], revealed a more energetic transitions intraligands regions from the strong character π receiver NO and MLCT band of transition dπFe(II)π*(NO).

Alquilação de tolueno com propeno, através de complexo ferro (II) ᵦ- diimina homogêneo e heterogeneizado em MCM-41, Al-MCM-41 e SBA-15

This work describes the synthesis and aplication of homogeneous and heterogenized iron catalysts in the alkylation reaction of toluene with propene, empolying experimental design. The homogenous complex was obtained trough the synthesis of the organic ligand folowed by the complexation of the iron(II) chloride. As to the heterogenized complexes, first were synthetized the inorganic supports (SBA-15, MCM-41 and Al-MCM-41). Then, it was synthetized the ligand again, that through funcionalization with chloropropyltrimethoxysilane (CPTMS), was anchored on the support previously calcinated. To these anchored ligands, was complexed the iron(II) chloride, previously solubilizated in tetrahydrofuran (THF). The organic ligand characterization was accomplished trough nuclear magnetic resonance (NMR) and Infrared spectroscopy (IV). The supports were characterized with x-ray diffraction (DRX), texture analysis with nitrogen adsorption/desorption (before and after the anchoring), termogravimetric analysis (TG) and infrared (IV). The metalic content was quantified trough the atomic absorption spectrophotometry (AAS). The complexes were tested in catalytic reactions emolying ethylaluminium sesquichloride (EASC) as co-catalyst in steel reactor, under mecanic stirring. The reaction conditions ranged from 4 to 36 ◦C, with many aluminum/iron ratios. The catalysts were actives in homogeneous and heterogenized ways. The homogenous catalytic complex showed a maximum turnover frequency (TOF) of 8.63 ×103 · h −1 , while, in some conditions, the anchored complexes showed better results, with TOF of until 8.08 ×103 · h −1 . Aditionally, it was possible to determine an equation, to the homogenous catalyst, that describes the product quantity in function of reacional temperature and aluminum/iron ratio.