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We explored the potential use of diatomite/Fe2O3/TiO2 composites as catalysts for heterogeneous photo-Fenton degradation of methylene blue under neutral pH. Such system consists in magnetic solids synthesized by co-precipitation with Fe2+/Fe3+ in the presence of diatomite, followed by impregnation of TiO2. The results showed that the optimal amount of the catalyst was 2.0 g L−1, since aggregation phenomena become significant above this concentration, which decreases the photodegradation activity. The catalyst is highly efficient in the degradation of methylene blue and shows an easy recovery by an external magnetic field. This allows for an effective catalyst reuse without significant loss of activity in catalytic cycles, which is a highly interesting prospect for recyclable dye degradation systems.

Este artigo analisa a formação de professores universitários, no contexto da pesquisa Curso Pedagogia Universitária: os professores e sua prática pedagógica desenvolvida pelo Grupo de Apoio Pedagógico do Campus USP-Ribeirão Preto/Universidade de São Paulo – Brasil – (GAPRP). Trata de pesquisa descritivo-exploratória, de natureza qualitativa que se propõe a analisar as reflexões de professores, participantes do I e II Curso de Pedagogia Universitária realizado em Ribeirão Preto em 2008 e 2009, acerca de sua prática pedagógica. Os dados revelam que as reflexões desses professores contemplam a revisitação de suas práticas pedagógicas, os limites contextuais e administrativos e a gestão do projeto político pedagógico com possibilidades de mudanças. Evidenciam-se também alguns pontos de tensão que necessitam ser trabalhados: aprendizagem da docência como perspectiva individual versus docência como perspectiva coletiva; formação pedagógica como prática sócio-política versus prática instrumental e valorização da pesquisa em detrimento do ensino.

The synthetic versatility and the potential applications of porphyrins and analogues in different fields have aroused special interest in their study, especially to mimic biological systems, such as cytochrome P-450. The ability of the porphyrin tetrapyrrolic core to accommodate metal ions of varying charges can modulate the type of application of these compounds. As a contribution, in this special number in honor to the Brazilian women who have devoted their lives to the growth and dissemination of chemistry knowledge, we report the advances in porphyrin research in Brazil for catalytic purposes and other applications, beginning at the Universidade de Sao Paulo (USP) at Ribeirao Preto. We also discuss some works that have resulted from joint research effort between Brazilian researchers and Portuguese colleagues from the Universidade de Aveiro, Portugal, working in the porphyrin field.

We have immobilized iron porphyrins on SBA-type mesoporous silica matrixes for application in hydrocarbon oxidation. Understanding the role the silica surface has in this process is crucial when developing biomimetic catalysts with improved activity. More specifically, we immobilized 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin iron(III) chloride (FeP) on SBA-15 structures modified with (3-aminopropyl)triethoxysilane (APTES), designated FeP-APSBA. We prepared a second class of catalyst via reaction of FeP-APSBA with 1,1,1,3,3,3-hexamethyldisilazane (HMDS), so that non-polar Si–(CH3)3 (TMS) groups partially replaced surface Si–OH groups and yielded the FeP-APSBA-TMS catalyst. Goniometric measurements of contact angles with different solvents confirmed that surface polarities changed as expected; these measurements also allowed determination of surface free energies. FTIR, 29Si CP-MAS NMR, atomic absorption spectrometry and UV-Vis spectroscopies, SAXS, thermal analyses, scanning/transmission electron microscopy (SEM/TEM), and N2 adsorption/desorption isotherms helped to characterize the prepared materials. Hydrocarbon oxidations enabled us to correlate surface changes with catalyst structure and activity. Surprisingly, the Si–OH groups played an important part in the adsorption of iodosylbenzene molecules, used as oxygen donors during the oxidation reactions. In addition, the TMS end-capped groups negatively affected catalytic performance. In conclusion, the catalytic assays demonstrated the high catalytic potential of iron porphyrins immobilized on SBA-15 and attested to their biomimetic behavior.

This study reports on the preparation of heterogeneous catalysts with two different pore sizes, the Fe3O4@nSiO2@MCM-41-MnP and Fe3O4@nSiO2@MCM-41(E)-MnP catalysts. Such systems ally the catalytic properties of metalloporphyrins (MeP) with the magnetic properties of magnetite nanoparticles (Fe3O4) in a mesoporous MCM-41 silica matrix. The synthesis of Fe3O4 nanoparticles was followed by the surface coating with a thin silica layer (Fe3O4@nSiO2). Then, an MCM-41-type ordered mesoporous silica structure was grown over the initial particles in the presence of CTAB as surfactant and TEOS as the silica precursor, to yield the Fe3O4@nSiO2@MCM-41 solid. In this step, mesitylene can also be incorporated as a structure expanding agent for the production of larger pores, thus yielding the Fe3O4@nSiO2@MCM-41(E) solids. The resulting composites were further functionalized with aminopropyl groups by the silylating agent APTES. This enabled the covalent immobilization of manganese(III)-5,10,15,20-tetrakis(pentafluorophenyl)porphyrin (Mn(TPF5PP)) onto the composites via a aromatic nucleophilic substitution reaction, to afford the Fe3O4@nSiO2@MCM-41-MnP and Fe3O4@nSiO2@MCM-41(E)-MnP catalysts. Characterization of the catalysts by XRD, UV–Vis, DR UV–vis, FTIR, SEM, TEM, VSM and N2 adsorption/desorption isotherms, aided understanding the catalyst structure and morphology. The catalytic activity of the catalysts in hydrocarbon oxidation ((Z)-cyclooctene and cyclohexane) was evaluated; iodosylbenzene (PhIO) was used as the oxygen donor agent. The catalytic tests demonstrated higher yields of epoxide for Fe3O4@nSiO2@MCM-41(E)-MnP than Fe3O4@nSiO2@MCM-41-MnP catalyst, which can be attributed to the larger pore sizes. Both catalysts were selective for the cyclohexanol product, thus indicating a P450-type biomimetic behavior.

University pedagogy has been promoted in the context of the policy for valuing undergraduate training at the University of São Paulo (USP). In this regard, one action of the Undergraduate Pro-Rectory was the creation of pedagogic support groups. The objective of this study is to report and analyze the strategies for university teacher training developed by the Pedagogic Support Group at the Ribeirão Preto Campus (GAPRP/USP–Grupo de Apoio Pedagógico do Campus de Ribeirão Preto), during the period from 2002 to 2015. The group takes on a conception of teacher training that extrapolates the technical dimension, considering political-social and historical determinants that have shaped the university, undergraduate teaching, and the faculty, as well as the valorization of strategies promoting reflection, theoretical-practical articulation, and collective learning. During the day-to-day monitoring of these education strategies, a few aspects are highlighted and analyzed: identification of the need for pedagogic training as an individual initiative of the teaching staff, despite the policies for valuing undergraduate training; investment in continuous educational strategies and the education undergone by the faculty that compose GAPRP/USP. To conclude, teacher training means to value the construction of a political project so as to qualify university teachers.

Metalloporphyrins immobilized into NaY zeolite are described as catalysts for hydrocarbon oxyfuntionalization. Manganese(III) and iron(III)tetrakis(4-N-methylpyridyl)-porphyrin (MnP1 and FeP1), and manganese(III) and iron(III) tetrakis(4-N-benzylpiridil)-porphyrin (MnP2 and FeP2) were impregnated (MnP1-NaYimp, FeP1-NaYimp, MnP2-NaYimp, FeP2-NaYimp, respectively) and encapsulated (MnP1-NaY, FeP1-NaY, MnP2-NaY and FeP2-NaY) into the NaY zeolite. These catalysts were used in the oxidation of (Z)-cyclooctene, cyclohexane, and adamantane by iodosylbezene (PhIO). These systems were able to epoxidize (Z)-cyclooctene with cis-epoxycyclooctane yields as high as 100%. By using cyclohexane and adamantane as substrate, the susceptibility of the benzyl groups on the porphyrin ring of the MnP materials, led to a different distribution of the oxidized products. With FePs, this susceptibility was not detected because the species responsible for the oxidations, FeIV(O)P·+, is more active than MnV(O)P. In conclusion, cationic metalloporphyrins immobilized into NaX zeolites, are good cytochrome P-450 models is less polar solvents since the selectivity of the system indicates the “in cage” solvent oxygen rebound oxidative process.

The synthesis and photophysical evaluation of new chlorin derivatives are described. The Diels-Alder reaction between protoporphyrin IX dimethyl ester and substituted maleimides furnishes endo-adducts that completely prevent the self-aggregation of the chlorins. Fluorescence, resonant light scattering (RLS) and (1)H NMR experiments, as well as X-ray crystallographic have demonstrated that the configurational arrangement of the synthesized chlorins prevent π-stacking interactions between macrocycles, thus indicating that it is a nonaggregating photosensitizer with high singlet oxygen (Φ(Δ)) and fluorescence (Φ(f)) quantum yields. Our results show that this type of synthetic strategy may provide the lead to a new generation of PDT photosensitizers.

This work presents the synthesis and characterization of a series of substituted pyridylpentafluroporphyrins, including the separation of the cis- and trans-isomers, the latter being characterized by X-ray crystallography. The spectroscopic and electrochemical properties of the series are dependent on the number of electron withdrawing pentafluorophenyl substituent, but they do not depend on the symmetry of the molecule. Ongoing from the monosubstituted to the more substituted pentafluorophenyl porphyrin H2(MPyTFPP) derivative, the Soret bands are slightly red-shifted and their quantum fluorescence yields range from 0.035 to 0.046, consistent with the value of 0.045 for the fully substituted 5,10,15,20-tetrapentafluorophenylporphyrin (dichloromethane solutions). The redox potentials of the reductive processes of monoanion and dianion formation are also sensitive to the number of pentafluoro substituents, shifting 180 mV to more positive values for the P0/P-1process ongoing from the monopentafluoro to the tris-pentafluorophenyl substituted derivative.

The interaction between a hydrophobically modified 5,10,15,20-tetrakis(4-N-tetradecyl-pyridyl) porphyrin and three phospholipids: two negatively charged, DMPA (the sodium salt of dimyristoyl-sn-glycero-phosphatidyl acid) and DMPG (the sodium salt of 1,2-dimyristoyl-sn-glycero-3-[phospho-rac-(1-glycerol)]) and a zwitterionic DMPC (dimyristoyl-sn-glycero-phosphatidylcholine), were studied by means of surface pressure isotherms and spectroscopic methods. The interaction results in partial or total metallation of the porphyrin with zinc ions in the presence of negatively charged phospholipids, as attested by UV–vis and luminescence spectroscopy of the transferred films. In the presence of the zwitterionic phospholipid no insertion of zinc ion in the porphyrin ring is detected. These results are relevant for the understanding of photosensitizer-lipid-carrier binding for use in photodynamic therapy.

Syntheses of two water-soluble phthalocyanines (Pc) containing 5-aminolevulinic acid (ALA) linked to the core structure are described. These compounds were prepared by using original functionalizations, and they present remarkable structural and photophysical features, indicating that they could be applied to photodynamic therapy (PDT).

A simple synthesis of new amphiphilic chlorin derivatives from protoporphyrin-IX dimethyl ester is reported. The preparation of such compounds is based in a straightforward methodology, which involves the Diels–Alder reaction of protoporphyrin-IX dimethyl ester with maleic anhydride followed by addition of nucleophilic species to the initially formed cycloadducts, a transformation, which is highly regioselective. Preliminary photophysical studies with the new compounds show that they meet adequate features for PDT applications.

The novel asymmetric metallo-organic triads cis- and trans-[B(4-py)BPFPH2{Ru3O(Ac)6(py)2}{Ru(bpy)2Cl}](PF6)2 (5a,b) for which cis- and trans-B(4-py)BPFPH2 = 5,10-bis(pentafluorophenyl)-15,20-bis(4-pyridyl)porphyrin and 5,15-bis(pentafluorophenyl)-10,20-bis(4-pyridyl)porphyrin, respectively; Ac = acetate; py = pyridine and bpy = 2,2′-bipyridine, as well as their corresponding monosubstituted dyads cis- and trans-[B(4-py)BPFPH2{Ru3O(Ac)6(py)2}]PF6 (4a,b) have been structurally characterized via electrospray ionization mass spectrometry (ESI-MS and ESI-MS/MS). The ESI-MS of dyads 4a,b display two characteristic Ru-multicomponent clusters of isotopologue ions corresponding to singly charged ions 4a,b+ of m/z 1629 and doubly charged ions [4a,b+H]2+ of m/z 815 and the triads 5a,b are detected by ESI-MS as the intact doubly charged cluster of isotopologue ions of m/z 1039 [5a,b]2+. The ESI-MS/MS of 4a,b+, [4a,b+H]2+ and [5a,b]2+ reveal characteristic dissociation pathways, which confirm the structural assignments providing additional information on the intrinsic binding strengths of the gaseous ions. Although the gas-phase behavior of each pair of isomers was rather similar, the less symmetric dyads 4a,b are distinguished via the 1H NMR spectral profile of the pyrrolic signals. Exploratory photophysical assays have shown that both modifying motifs alter the porphyrinic core emission profile, opening the possibility to use these asymmetric systems as photophysical devices.

We successfully immobilized metalloporphyrins (MeP) in mesoporous silica coating magnetite spheres. In this sense, we prepared two different classes of core@shell supports, which comprise aligned (Fe3O4-AM-MeP, MeP=FeP or MnP) and non-aligned (Fe3O4-NM-MeP, MeP=FeP or MnP) mesoporous magnetic structures. X-ray diffractometry and energy dispersive X-ray spectroscopy confirmed the mesoporous nature of the silica shell of the materials. Magnetization measurements, scanning and transmission electron microscopies (SEM/TEM), electrophoretic mobility (ζ-potential), and infrared spectroscopy (FTIR) also confirm the composition and structure of the materials. The catalysts maintained their catalytic activity during nine reaction cycles toward hydrocarbon oxidation processes without detectable catalyst leaching. The catalysis results revealed a biomimetic pattern of cytochrome P450-type enzymes, thus confirming that the prepared materials are can effectively mimic the activity of such groups.

In recent years, because of the need for a more flexible curriculum established by the Curriculum Guidelines of the National Brazilian Education (law 9394/96), the pedagogical project of the Chemistry course of FFCLRP/USP has undergone alterations, amongst them the gradual reduction of the hours devoted to the discipline Qualitative Analytical Chemistry. In this context, this discipline has been carefully analyzed and reorganized in order to allow the elimination of redundancies and the introduction of activities considered important for the professional formation of both chemists and chemistry teachers. In this work, we will discuss the main strategies adopted in this reorganization with the objective of making the teaching/learning process more dynamic and efficient.

A novel water-soluble asymmetrical sugar-phthalocyanine was prepared via a statistical cross-condensation of tetrakis(1,2:3,4-di- O -isopropylidene-α- d -galactopyranos-6-yl)phthalonitrile with phthalonitrile. The new compound, with amphiphilic character, can be useful as a selective photosensitizer in photodynamic therapy, as well as for constructing phthalocyanine-based supramolecular systems.

Manganese(III) tetrakis(2,6-dichloro-3-sulfonatophenyl)porphyrin (1) and manganese(III) tetrakis[tetrafluoro-4-(trimethylammoniumyl)phenyl]porphyrin (2), in homogeneous solution and supported on modified silica surfaces, have been used as catalysts for the oxidation of pentane and cyclohexane with iodosylbenzene. The effects of reaction solvent, catalyst support and dioxygen on the oxidation yields and product distributions have been studied. The reactions under nitrogen show a high selectivity for alcohol formation whereas in air ketones become significant products, indicating the participation of dioxygen in the formation of the ketones. Competitive oxidations of pentane and perdeuteropentane give kinetic isotope effects (kH/kD) of 6.9 ± 1.3 for both pentan-2-ol and -3-ol formation. The results are in accord with a mechanism in which an initial hydrogen atom-abstraction from the alkane by the active oxidant, an oxomanganese(V) species, gives a solvent-caged alkyl radical and a hydroxymanganese(IV) porphyrin. All the products can be accounted by partitioning of the carbon radicals between ‘in cage’ reaction to give alcohol and ‘cage escape’ leading to products typical of free alkyl radicals. The effect of solvent viscosity on this partitioning of the carbon radicals has been probed with the radical trap bromotrichloromethane.

Herein we present the first Mn–K edge EXAFS spectra recorded for manganese(III)porphyrin catalysts containing [Mn{T(4- N -MePy)P}(L) n ] 5+ (where L = oxygenated or nitrogenated axial ligands, n = 1 or 2) grafted onto modified silica-surfaces with propylimidazole, IPG ( 3 ), sulfonatophenyl, SiSO 3 − ( 4 ), and both, SiSO 3 − IPG ( 5 ), where T(4- N -MePy)P is the ligand 5,10,15,20-tetra(4- N -methylpyridyl)porphyrinate. From the data analysis and the refinement results, we have obtained the following structural information concerning to the coordination environment around the Mn(III) ion: four Mn–N at 2.00 A and two Mn–N/O axial at 2.26 A for 3 ; four Mn–N at 2.03 A and two Mn–O axial at 2.27 A for 4 , and four Mn–N at 2.02 A and two Mn–N/O axial at 2.28 A for 5 . Correlations of EXAFS data with UV–vis spectra pattern and other properties such as colors of the materials allowed distinguishing between materials 3 , 4 and 5 . Materials 4 and 5 belong to the same category, which involves ionic complex–support interaction. Furthermore, there are evidences for the coordination of the imidazolic ligand to the manganese(III) ion in 3 and 5 from qualitative analysis of XANES data. In the case of the catalyst 5 , bearing both sulfonate and imidazole as functional groups, we have suggested that the nature of the [Mn{T(4- N -MePy)P}(L) n ] 5+ –support interaction is predominantly of ionic character, even though the existence of Mn–imidazole bonds can be detected.

Novel cationic porphyrin derivatives having a galactose or a bis(isopropylidene)galactose unit linked directly to a pyridine or to an aminophenyl group were characterized by electrospray tandem mass spectrometry (ESI-MS/MS). The electrospray mass spectra (ESI-MS) show the M(+) ions, since these porphyrins are already monocharged in solution. The fragmentation of these ions under ESI-MS/MS conditions was studied and it was found that elimination of the sugar residue as a radical (-163 or -243 Da) is a common fragmentation pathway. Loss of the sugar unit as a neutral fragment (-162 or -242 Da) and cross-ring fragmentations typical of glyco-derivatives are also observed for the pyridinium glycoporphyrins, but they are absent in the case of ammonium glycoporphyrins. The cationic beta-pyridiniumvinyl porphyrins show an atypical fragmentation due to the cleavage of the C(5)-C(6) bond of the sugar unit. Overall, the different patterns of fragmentation observed in the ESI-MS/MS spectra of the sugar pyridinium porphyrins and of the sugar ammonium phenyl porphyrins can give important information about the type of spacer between the porphyrin and the sugar unit.

The novel fluorinated metallochlorin 5,10,15,20-tetrakis(pentafluorophenyl)-tetrahydro-1 H - N -methyl-pyrrolo[3,4- b ]-porphyrinato manganese(III), Mn(chlor)-1 , and its methylated derivative, Mn(chlor)-2 , have been studied as catalysts in the oxyfunctionalisation of cyclohexane with two oxidants, namely iodosylbenzene (PhIO) and H 2 O 2 . For comparison reasons two metalloporphyrins have been also used: the neutral 5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato manganese(III), Mn(porph)-1 , and the cationic 5,10,15,20-tetrakis(2,3,5,6-tetrafluoro-4-trimethylammoniumphenyl)porphyrinato manganese(III), Mn(porph)-2 . It has been possible to verify a different reactivity in the H 2 O 2 -oxyfunctionalisation of alkanes from studies using the radical inhibitor bromotrichloromethane and competitive cyclooctane/ cis -cyclooctene oxidations. The results suggest that the formation of alcohols and ketones from the oxidation of cyclohexane occurs mainly from a free alkyl radical mechanism, which requires a Mn V O species to abstract a hydrogen atom from the alkane to generate the alkyl radical. On the other hand, the Mn(chlor)/H 2 O 2 system possibly yields, in a first step, the Mn III OOH species, but this is not reactive enough to generate Mn V O. The Mn(chlor) hydroperoxy complex shows low efficiency in the production of the alkyl radical, leading to small amounts of alcohol and ketone. However, it seems to be an efficient species for selective epoxidation, as can be observed in the competitive cyclooctane/ cis -cyclooctene oxidation reaction.

In this work the iron(III)tris(4-N-methylpyridyl)-mono(pentafluorophenyl)-porphyrin, [Fe{T(4-N-MePy)MFPP}]Cl4, was impregnated (FeP-NaYimp) and encapsulated (FeP-NaY) in the NaY zeolite and had been used as catalyst in the hydrocarbon oxidation by iodosylbenzene (PhIO) in 1,2-dichloroethane. Cyclohexane, (Z)-cyclooctene and adamantane were used as substrate. In the case of cyclohexane, both homogeneous (FePCl4) and heterogeneous (FeP-NaYimp and FeP-NaY) systems are 100% selective towards the formation of cyclohexanol, indicating that oxygen rebound mechanism is operating. The same systems were able to epoxide (Z)-cyclooctene with yields of 92% of cis-epoxycyclooctane for heterogeneous catalysts. For the FePCl4 system the yield of cis-epoxycyclooctane obtained was 40%. Probably, this fact is due the low solubility of the FeP in this organic media (1,2-dichloroethane) because when the Cl− counter-ions were exchanged for PF6− and the solvent used was a mixture consisting of 1,2-dichloroethane/acetonitrile (1:1) the yield of cis-epoxycyclooctane increased from 40 to 95%. Hydroxylation of adamantane shows a preferable alkane oxidation at the terciary CH bonding as expected for a P-450 model system. The total adamantanol yields were 58, 66 and 81% for [Fe{T(4-N-MePy)MFPP}]Cl4 in solution, [Fe{T(4-N-MePy)MFPP}]Cl4-NaYimp and [Fe{T(4-N-MePy)MFPP}]Cl4-NaY, respectively. Concerning selectivity, the 1-adamantanol (Ad-1-ol)/2-adamantanol (Ad-2-ol) ratio of 19:1 for [Fe{T(4-N-MePy)MFPP}]Cl4 in solution, 19:1 for [Fe{T(4-N-MePy)MFPP}]Cl4-NaYimp and 17:1 for [Fe{T(4-N-MePy)MFPP}]Cl4-NaY were obtained (after statistic correction). These data indicate a free radical activation of the CH bonds of adamantane, as is expected for a P-450 model. 2-Adamantanone was not obtained in any of the cases.

In this work, different iron porphyrins, either immobilised on silica surface or encapsulated in silica matrix (FePES), have been used as catalyst in hydrocarbon oxidation by PhIO or H2O2, and results have been compared. Such study has aimed at understanding the relationship between the catalytic results and the following properties of the catalytic reaction sites: (i) the coordination environment around the central iron, which can change substrate binding; (ii) the nature of the support, since polarity can affect substrate accessibility to the active site; (iii) the FeP nature and the microenvironment it create. We have observed that all systems are able to oxidise (Z)-cyclooctene and cyclohexane, and better product yields are obtained with the supported systems. In the case of FePES, high cyclohexanol and epoxide yields are obtained with the electronegatively substituted Im-[FeTFPP]ES. The low yields obtained with the cationic FePES can be explained by the polar environment of the FeP active site, which hinders the oxygen rebound mechanism necessary for the hydroxylation of the inert cyclohexane. As for the supported systems, commercial silica leads to high epoxidation and hydroxylation yields, showing that cationic iron porphyrins are efficient catalysts even when immobilised on a simple support. The use of the clean oxidant H2O2 for olefin epoxidation in cases of the 2- and 4-N-methyl-pyridyl substituted FePs in heterogeneous systems is reported for the first time in this paper, and the results are comparable with literature data on electron-deficient FePs in homogeneous systems. The best catalyst is [Fe(TF4TMAPP)]5+ on the SiSH and SiO2 supports rendering 80% and 86% epoxide yields with H2O2, respectively. All materials have been characterised by BET analysis, UV–vis and EPR spectroscopies.

This paper reports an HPLC–MS/MS investigation of praziquantel (anthelmintic agent) oxidation by iodosylbenzene in an organic medium, using iron(III) tetraarylporphyrins (where aryl = phenyl, pentafluorophenyl, 2-nitrophenyl, 2-trifluoromethylphenyl and mesityl) and manganese(III) tetraphenylporphyrin as catalysts. The majority of the oxidation products have been identified by sequential MS and NMR analyses. The selectivities of the oxidations by these cytochrome P-450 models are studied and compared. Time dependent reaction profiles suggest that with all the catalysts, the initial oxidation occurs predominantly at the 7-position. With Fe(T2TFMPP)Cl the yield and selectivity (64%) for 7-hydroxypraziquantel remain high even after 24 h reaction, whereas with the other catalysts this initial product is further oxidized to di- and trihydroxypraziquantel. The Fe(TFPP)Cl system results in the higher yield (11%) of cis - and trans -4′-hydroxypraziquantel, the major metabolites from in vivo and in vitro metabolism of praziquantel by cytochrome P-450 monooxygenases.

The behavior of three Mn(III)porphyrins with different polarities at air/water interfaces and their interaction with the phospholipid dimyristoylphosphatidic acid (DMPA) were studied through surface potential and pressure–area isotherms. Multilayer films of Mn(III)porphyrin have been formed at air/liquid interfaces. Some DMPA–Mn(III)porphyrin mixed monolayers have provided a second transition of phases around 20 mN/m absent in pure DMPA monolayers. This transition has been explained on basis of the re-arrangement of DMPA molecules within free spaces existent among Mn(III)porphyrin molecules and also by the interaction of metallic center of the complex with the negatively charged phosphate groups of DMPA. Changes on the geometry of Mn(III)porphyrin has been considered as an important factor that drives DMPA reorganization at air/water interfaces.

The sol-gel process is a methodology used to obtain organic-inorganic hybrid solids, which open new possibilities in the field of material science. The sol-gel technique offers a low temperature attractive approach for introducing organic molecules into amorphous materials. In order to introduce tetrakis (2-hydroxy-5-nitrophenyl)porphyrin covalently bounded to a silicate matrix, the inorganic precursor 3-isocyanatopropyltriethoxysilane was added (molar ratio 2:1) to the porphyrin solution in anhydrous dimethylformamide and triethylamine. The isolated porphyrin and the hybrid porphyrinosilica have excitation maximum centred at 400 nm and 424 nm, respectively and the emission spectra for both materials has bands centred at 650 nm and 713 nm. The formation of hybrid matrix was investigated by FTIR.

Ionic Fe(III)porphyrins pentafluorophenyl-derivatives: 5,10,15-tris(pentafluorophenyl)-20-(4-N-methylpyridyl)porphyrin iron(III) ([Fe{M(4-N-MePy)TPFP}]2+), 5,10,15-tris(4-N-methylpyridyl)-20-(pentafluorophenyl)porphyrin iron(III) ([Fe{T(4-N-MePy)MPFP}]4+) and 5,10,15-tris(pentafluorophenyl)-20-(3-sulfonatophenyl)porphyrin iron(III) ([Fe{M(3-SO3P)TPFP}]) immobilised on silica gel (SiO2) and modified silica with sulfonatophenyl (SiSO3−), propylimidazole (IPG), sulfonatophenyl plus propylimidazole (SiSO3−(IPG)), propyltrimethylammonium (SiN+) and propyltrimethylammonium plus propylimidazole (SiN+(IPG)) were studied in the epoxidation of (Z)-cyclooctene by H2O2. The better yields of product, cis-epoxycyclooctane, were achieved with the catalytic systems, [Fe{M(4-N-MePy)TPFP}]-SiSO3(IPG), [Fe{M(3-SO3P)TPFP}]-IPG and [Fe{M(3-SO3P)TPFP}]-SiO2, where is more probable to have available sulfonatophenyl groups. That is, where there is no ionic binding Fe(III)porphyrin-support via sulfonatophenyl. A charge effect supplied by the available sulfonatophenyl residues and a more polar microenvironment provided by the silica-support promote the heterolytic cleavage of the OO bond, which is essential to obtain high yields of products in oxidation reactions. Effects of general acid–base catalysis, as occurs in enzymes, and higher reduction potential provided by electron-withdrawing groups, present on porphyrin ring or axial ligand, as recently reported by Nam and coworkers for homogeneous Fe(III)porphyrins, to promote the heterolysis of the OO bond are ruled out.

The properties, morphology and catalytic activity of an iron(III)-tetra-o-ureaphenylporphyrinosilica (FePS), obtained using two nitrogenous bases as catalysts in the sol–gel process, are reported. Electron paramagnetic resonance spectra have components due to FeIII high spin, a component at g∼4.3 due to porphyrins species in rhombic symmetry and a component in the region of 0.2 to 0.3 T attributed to Fe–Fe coupling. The solid samples have surface areas 645 and 723 cm2/g, the adsorption isotherms of the solids are type II and the hysteresis loop is type H1. The solids have porosity classified between meso- and macro- porous containing pores with regular morphology and cylindrical and/or polyhedral geometry. Scanning electron microscopy detects an amorphous material composed of aggregates and granules. The matrix effect on the catalytic activity of the FePS, in the Z-cyclooctene oxidation, using iodosylbenzene (PhIO) as oxygen donor was verified. In the repeat-use experiment with FeP:PhIO molar ratio of 1:2000, the total turnover number was 670 for FePS-py, while for the corresponding homogeneous system it was 342.

A series of iron(III)porphyrins containing NO2-substituents in the meso-ortho-phenyl or COOH-substituents in the meso-para-phenyl rings (FeP) have been used to catalyse hydrocarbon oxidation by iodosylbenzene. The FeP series were efficient and selective catalysts for alkene epoxidation and alkane hydroxylation. The most promising iron porphyrin, 5,10,15-tri(2-nitrophenyl)20-mono-(4-carboxyphenyl)porphyrin iron(III) chloride, Fe(TNMCPP)Cl, was covalently bound to aminopropylated silica (APS) through covalent binding between COOH groups in the FeP (after activation by reaction with SOCl2) and NH2 groups on the funcionalised silica resulting in the anchored catalyst SiNH(TNMCPP)FeCl. This system proved to be a highly efficient catalyst for alkene epoxidation. The same iron porphyrin was also supported on APS through electrostatic binding, resulting the heterogeneous catalyst SiNH3+(TNMCPP)FeCl. The iron centres are in different surroundings on the two supports as demonstrated by EPR, UV/VIS and oxidation reactions results. The SiNH3+(TNMCPP)FeCl is not a good catalyst for hydrocarbon oxidation, which can be attributed to the higher polarity of this support and the bis-axial coordination by the free NH2 groups of the support with the iron centre. Both effects are unfavourable for the interaction between the non-polar substrates and the catalyst.

The cationic manganese porphyrins: manganese(III) 5,10,15-tris(2,6-dichlorophenyl)-20-(4- N -methylpyridyl)porphyrin ([Mn{M(4- N -MePy)TDCPP}] 2+ ), 5,10,15,20-tetra(2,3,5,6-tetrafluoro-4-trimethylammoniumphenyl)porphyrin ([Mn(TF4TMAPP)] 5+ ) and 5,10,15,20-tetra(4- N -methylpyridyl)porphyrin ([Mn{T(4- N -MePy)P}] 5+ ) supported on silica modified with propylimidazole (IPG), sulfonatophenyl (SiSO 3 − ) and both propylimidazole and sulfonatophenyl (SiSO 3 − (IPG)) have been studied as catalysts in the epoxidation of ( Z )-cyclooctene and oxidation of cyclohexane. High yields of products were obtained using PhIO as oxidant without leaching, except for the IPG, of the catalyst from the surface of the support. The catalysts also have been used with H 2 O 2 in the epoxidation of ( Z )-cyclooctene with and without a co-catalyst (imidazole or ammonium acetate). The best catalyst [Mn{T(F4TMAPP)}]-SiSO 3 (IPG) achieved almost 200 turnovers of the product cis -epoxycyclooctane using ammonium acetate as co-catalyst. The analogous homogeneous systems have been studied for comparison, but they did not reach the same efficiency . With these studies the two-fold role of imidazole in oxygenations of hydrocarbons by H 2 O 2 and Mn(III) porphyrins was confirmed. The characterisation of supported metalloporphyrins by UV–VIS spectroscopy is reported too.

The optimised conditions for preparation of ironporphyrin (FeP)-template trapped silica obtained by the sol–gel process are analysed by fractional factorial design. The FeP iron 5,10,15,20-tetrakis(pentafluorophenyl)-porphyrin (FeTFPPCl), iron 5,10,15,20-tetrakis(2,6-dichlorophenyl-3-sulphonatophenyl)-porphyrin (FeTDCSPP(Na)4Cl), iron 5,10,15,20-tetrakis-p-carboxyphenylporphyrin (FeTCPP(Na)4Cl) and iron 5,10,15,20-tetrakis-p-methylpyridilporphyrin (FeTMPyP(Cl)5) were used. Pyridine or 4-phenylimidazole was used as template. Scanning electron microscopy (SEM) shows that the use of different porphyrins and conditions in the preparation of xerogel produce different product morphologies. The prepared materials have surface areas, between 300 and 1000 m2/g. The electron paramagnetic resonance spectra of trapped materials have characteristic signal of FeIII high spin, the presence of porphyrin species in a rhombic symmetry and porphyrin aggregates were also observed.

Manganese(III) complexes of tetra-anionic and tetra-cationic porphyrins have been immobilised on counter-charged, surface-modified silica supports and on organic ion-exchange resins. The reactions of these supported manganese(III) porphyrin systems and analogous uncharged homogeneous systems have been examined using cyclooctene and (E)- and (Z)-4-methylpent-2-ene epoxidations, with iodosylbenzene (PhIO) as the oxygen donor. Comparisons using the manganese porphyrin systems as catalysts for the epoxidation of cyclooctene in acetonitrile reveal that, in low turnover reactions (maximum 136 turnovers), they all give an essentially quantitative yield of epoxide although the heterogeneous reactions are significantly slower than the homogeneous analogues. In large scale repeat-use experiments, however, the supported catalysts are clearly superior, giving markedly better yields. The epoxidations of (E)- and (Z)-4-methylpent-2-ene with all the catalysts show a very high stereoretention, with the (Z)-alkene reacting faster than the (E)-isomer. The sterically hindered manganese(III) 5,10,15,20-tetrakis(2,6-dichloro-3-sulfonatophenyl)porphyrin (MnTDCSPP) shows the highest selectivity for the (Z)-isomer; by contrast the supported manganese(III) 5,10,15,20-tetrakis[2,3,5,6-tetrafluoro-4-(trimethylammonio)phenyl]porphyrin on Dowex (MnTF4TMAPP–Dowex) reacts with the two alkenes at effectively the same rate. The mechanism of the epoxidations and the influence of the porphyrin ligand and support on the substrate selectivity are discussed.

The approach adopted for the obtention of zeolite-encapsulated FeP led to clean syntheses of biomimetical catalyst. The catalysts were obtained through the zeolite synthesis method, where NaX zeolite was synthesised around one of the cationic FePs: iron(III) 5,10,15,20-tetrakis(4-N-methylpyridyl)porphyrin (FeP1) or iron(III) 5-mono(2,6-dichloro-phenyl)10,15,20-tris(4-N-methylpyridyl)porphyrin (FeP2). The syntheses yielded pure FeP1NaX and FeP2NaX catalysts without any by-products blocking the zeolite nanopores. FeP1NaX and FeP2NaX efficiently catalysed the epoxidation of (Z)-cyclooctene by iodosylbenzene (PhIO) in DCE, giving rise to cis-epoxycyclooctane yields of 85% and 95%, respectively. Hydroxylation of adamantane shows a preferable alkane oxidation at the tertiary CH bond, indicating a hydrogen abstraction through the FeIV(O)P·+species in the initial step. The total adamantanol yields were 52% and 45% for FeP1NaX and FeP2NaX, respectively. Concerning selectivity, FeP1NaX and FeP2NaX gave an 1-adamantanol (Ad-1-ol)/2-adamantanol (Ad-2-ol) ratio of 20:1 and 11:1, respectively (after statistical correction). Therefore, these results indicate a free radical activation of the CH bonds of adamantane as expected for P-450 models. In the cyclohexane oxidation catalysed by FeP1NaX in DCE, a cyclohexanol (C6-ol) yield of 50% and an alcohol/ketone ratio of 10 was obtained. The hydroxylation occurs according to the so-called oxygen rebound mechanism, as expected for a P-450 model system. FeP2NaX is less selective (C6-ol yield=25% and alcohol/ketone=1.2). One possible explanation is that a Russell-type mechanism involving O2 imprisoned within the zeolite cages may be operating parallelly, generating both C6-ol and cyclohexanone.

The synthesis of a hybrid network consisting of alternating porphyrin as optical active agent and siloxane units (porphyrinosilica) can be achieved by sol–gel process. Due to several applications of these hybrids, we search for new methods to prepare them. A porphyrinosilica with a urea linker was synthesized through the reaction of NH2 groups present in the phenyl rings of mesotetrakis p-aminophenyl porphyrin (TAMPPH2) with 3-isocyanatopropyltriethoxysilane (IPTES) followed by condensation with tetraethoxysilane (TEOS). The polymerization reactions were carried out in ethanol or dimethylformamide using acidic or basic catalysis. The formation of urea bonds was confirmed by infrared spectroscopy. The absorption and luminescence spectra confirmed the presence of porphyrin in the network and were also established by thermal analysis. Nuclear magnetic resonance 29Si data for the porphyrinosilica addressed the degree of condensation and the extent of network formation.

The optimized conditions for the preparation of a new manganese porphyrinosilica-template material are reported. The manganese porphyrinosilica-template was prepared by the sol–gel process, by the reaction of –SO 2 Cl groups present in the phenyl rings of MnTDC(SO 2 Cl)PPCl with 3-aminopropyltriethoxysilane. The reaction produces a precursor porphyrinopropylsilyl species, which were then polymerized with tetraethoxysilane. The presence of manganese porphyrin on xerogel is confirmed by ultraviolet visible absorption spectroscopy and thermogravimetric analysis (TGA). The prepared materials have surface areas between 19 and 674 m 2 g −1 . Electron spectroscopy imaging of the materials show that manganese distribution in the xerogel is uniform. Both manganese(III) porphyrinosilica-template and a similar iron(III) porphyrinosilica-template can catalyze the epoxidation of cyclooctene using iodozylbenzene as oxygen donor. The metalloporphyrinosilica-template presents catalytic activity similar to that of metaloporphyrin in solution.

We present the synthesis of a hybrid material containing fluorinated iron porphyrins through hydrolysis and polycondensation of iron porphyrin bearing a trifluorosilyl function with tetraethoxysilane in the presence of nitrogen bases acting as template molecules. The presence of metalloporphyrin Soret band is detected in the ultraviolet–visible absorption spectra of all metalloporphyrinosilica-templates. Thermogravimetric analysis and electron paramagnetic resonance of the materials also confirm the presence of metalloporphyrin in a silica network. Electron spectroscopy imaging was that of a non-crystalline microstructure. The iron and silicon distribution are homogeneous for the elements in all particle sites. The iron porphyrinosilicas-template were active as catalysts for cyclooctene epoxidation using iodozylbenzene as oxygen donor. In general, the epoxidation yield is larger for iron porphyrinosilicas-template than for manganese porphyrinosilicas-template. The manganese porphyrinosilicas-template had a smaller activity due to their manganese oxidation state. The largest catalytic yield were obtained with the iron porphyrinosilica-pyridine (85%).

A novel supermolecule constituted by four μ 3 -oxo-triruthenium acetate clusters coordinated to manganese(III)- meso -tetra(4-pyridil)porphyrin acetate ([MnTPyP]CH 3 COO) has been synthesized. Characterization has been performed by UV–Vis and 1 H NMR spectroscopy. The electrochemical behavior (cyclic voltammetry and spectroelectrochemistry) in N , N ′-dimethylformamide has been analyzed in terms of five redox processes: three related to peripheral clusters (Ru IV,III,III /Ru III,III,III /Ru III,III,II /Ru III,II,II ) and two centered on the Mn–porphyrin core (Mn III P/Mn II P/Mn II P 2− ). A direct comparison has been performed between MnTCP and MnTPyP as catalysts for the cyclooctene and cyclohexane oxidation reactions. The improved selectivity exhibited by the supramolecular catalyst for cyclohexane oxidation has been ascribed to electronic effects on the oxomanganese(V) porphyrin species induced by the four peripheral clusters, in the formal Ru IV Ru III Ru III oxidation state.

New materials porphyrinosilica and metalloporphyrinosilica template have been obtained by a sol-gel processing where functionalyzed porphyrins and metalloporphyrins "building blocks" were assembled into a three-dimensional silicate network. The optimized conditions for preparation of these materials are revised. The monomer precursors porphyrinopropylsilyl and metalloporphyrinopropylsilyl preparation reactions and subsequent one pot sol-gel processing with tetraethoxysilane are discussed. In the case of metalloporphyrins the nitrogen base coordinates to the central metal and acts as a template in the molecular imprinting technique. UV-visible absorption spectroscopy, thermogravimetric analysis, electron paramagnetic resonance, nuclear magnetic spectra, infrared spectra, luminescence spectra, surface area and electron spectroscopy imaging of the materials are used to characterize the prepared materials. The catalytic activities of these metalloporphyrinosilica- template are compared.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:58:49Z No. of bitstreams: 1 S0103-50532000000500005.pdf: 190509 bytes, checksum: 2bc1d49b5678f0ebc0ec0adbb660b532 (MD5) Made available in DSpace on 2013-08-22T18:58:49Z (GMT). No. of bitstreams: 1 S0103-50532000000500005.pdf: 190509 bytes, checksum: 2bc1d49b5678f0ebc0ec0adbb660b532 (MD5) Previous issue date: 2000-10-01 Made available in DSpace on 2013-09-30T19:54:53Z (GMT). No. of bitstreams: 2 S0103-50532000000500005.pdf: 190509 bytes, checksum: 2bc1d49b5678f0ebc0ec0adbb660b532 (MD5) S0103-50532000000500005.pdf.txt: 39972 bytes, checksum: c8b1dabcdf29b072b2563b56979a599f (MD5) Previous issue date: 2000-10-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T14:18:56Z No. of bitstreams: 2 S0103-50532000000500005.pdf: 190509 bytes, checksum: 2bc1d49b5678f0ebc0ec0adbb660b532 (MD5) S0103-50532000000500005.pdf.txt: 39972 bytes, checksum: c8b1dabcdf29b072b2563b56979a599f (MD5) Made available in DSpace on 2014-05-20T14:18:56Z (GMT). No. of bitstreams: 2 S0103-50532000000500005.pdf: 190509 bytes, checksum: 2bc1d49b5678f0ebc0ec0adbb660b532 (MD5) S0103-50532000000500005.pdf.txt: 39972 bytes, checksum: c8b1dabcdf29b072b2563b56979a599f (MD5) Previous issue date: 2000-10-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) As porfirinas aniônicas 5,10,15-tris(4-carboxifenil), 20-mono(2-nitrofenil) porfirina (1), 5,10(ou 15)-bis(4-carboxifenil), 15(or 10),20-bis(2-nitrofenil)porfirina (2) and 5-mono(4-carboxifenil), 10,15,20-tris(2-nitrofenil)porfirina (3), foram sintetizadas diretamente através da reação de pirrol com os benzaldeídos substituídos em meio de ácido propiônico/nitrobenzeno. A relação molar dos benzaldeídos foi controlada para otimizar a síntese e purificação das porfirinas desejadas. Esta nova série de porfirinas foi caracterizada por cromatografia em camada delgada, espectrometria de massas (FAB MS), RMN ¹H, UV/Vis, IV e eletroquímica. As porfirinas 5,10,15,20-tetrakis(4-carboxifenil)porfirina (4) e 5,10,15,20-tetrakis(2-nitrofenil)porfirina (5) também foram estudadas para comparação, tornando a série completa. A redução eletroquímica das porfirinas base livre e correspondentes ferro(III) porfirinas foi investigada em eletrodos de carbono e mercúrio. Os potenciais de redução mostraram a dependência esperada do número de grupos nitro, fortemente retirador de elétrons, presentes no anel porfirínico, fornecendo evidências adicionais para a caracterização dos compostos sintetizados. The anionic 5,10,15-tris(4-carboxyphenyl), 20-mono(2-nitrophenyl) porphyrin (1), 5,10(or 15)-bis(4-carboxyphenyl), 15(or 10),20-bis(2-nitrophenyl)porphyrin (2) and 5-mono(4-carboxyphenyl), 10,15,20-tris(2-nitrophenyl)porphyrin (3) were sinthesized directly by reaction of pyrrole with substituted benzaldehydes in nitrobenzene/propionic acid media. The benzaldehydes molar ratio was controlled to optimize the synthesis and purification of the desired porphyrins. This new series of porphyrins was characterised by TLC, mass spectrometry (FAB MS), ¹H NMR, UV/Vis, IR and electrochemistry. 5,10,15,20-Tetrakis(4-carboxyphenyl)porphyrin (4) and 5,10,15,20-Tetrakis(2-nitrophenyl)porphyrin (5) were also characterised for comparative purposes, completing the series The electrochemical reduction was investigated for the free base and corresponding iron(III) porphyrins on glassy carbon and mercury electrodes. The reduction potentials showed the expected dependence on the number of electron-withdrawing nitro groups present on the porphyrin ring providing additional evidences for the characterisation of the synthesised compounds. Universidade de São Paulo Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto Departamento de Química Universidade Federal de São Carlos (UFSCar) Departamento de Química Universidade Estadual Paulista Instituto de Química Universidade Estadual Paulista Instituto de Química

This work describes a simple and economical experiment for the extraction and purification of chlorophyll a from Spirulina maxima. Extraction and purification of natural compounds can be considered one of the most illustrative experiments that can be performed in Organic Chemistry courses. Particularly, the chromatography of dyes and pigments allows students to have a better comprehension of the chromatography separations. These compounds represent an important class of organic pigments applied in pharmaceutical, cosmetic, detergent compositions, and various other fields and can be extracted from plants and algae. To extract, separate and purify chlorophyll a from associated pigments such as xanthophylls, carotenes, and pheophytins, very costly processes are reported. The present approach is perfectly adequate for use in Chemistry experiments for undergraduate students.