Encontrados 14 documentos, a visualizar página 1 de 2
Energy Transfer from Fluorene Based Conjugated Polyelectrolytes to Onchain and ...
Marques, Ana T.; Pinto, Sara M. A.; Monteiro, Carlos J. P.; Melo, J. Sérgio Seixas de; Burrows, Hugh D.; Scherf, Ullrich; Calvete, Mário J. F.A new water soluble fluorene-based polyelectrolyte containing on-chain porphyrin units has been synthesized via Suzuki coupling, for use in optoelectronic devices. The material consist of a random copolymer of poly{1,4-phenylene-[9,9-bis(4-phenoxy butylsulfonate)]fluorene-2,7-diyl} (PBS-PFP) and a 5,15-diphenylporphyrin (DPP). The energy transfer process between the PBS-PFP units and the porphyrin has been inve...
Palladium-catalysed reactions of 8-hydroxy- and 8-benzyloxy-5,7-diiodoquinoline...
Takács, Attila; Szilágyi, Antal; Ács, Péter; Márk, László; Peixoto, Andreia F.; Pereira, Mariette M.; Kollár, LászlóVarious 5-carboxamido-7-iodo-8-benzyloxyquinolines were synthesised via selective aminocarbonylation of 5,7-diiodo-8-benzyloxyquinoline in the presence of ‘in situ’ generated palladium(0) catalysts. Under similar conditions (50 °C, 80 bar CO), 5,7-bis(N-tert-butyl-glyoxylamido)-8-hydroxyquinoline was obtained using tert-butylamine as N-nucleophile. The unprotected 5,7-diiodo-8-hydroxyquinoline underwent dehydro...
Argilas como catalisadores verdes na esterificação do colesterol: caracterizaçã...
Maria,Teresa M. R.; Nunes,Rui M. D.; Pereira,Mariette M.; Eusébio,M. Ermelinda S.A laboratory experiment that enables the professor to introduce the problematic of sustainable development in pharmaceutical chemistry to undergraduate students is proposed, using a simple synthetic procedure. Cholesteryl acetate is prepared by the esterification of cholesterol using Montmorillonite K10 as heterogeneous catalyst. Cholesterol and cholesteryl acetate are characterized by spectroscopic (¹H RMN, 13...
Rhodium catalyzed hydroformylation of kaurane derivatives: A route to new diter...
Peixoto, Andreia F.; Melo, Daniela S. de; Fernandes, Tânia F.; Fonseca, Yuraima; Gusevskaya, Elena V.; Silva, Artur M. S.; Contreras, Ricardo R.Kaurenic and grandiflorenic acids are naturally occurring diterpenes whose biological activity has been described. Both acids contain an exocyclic methylenic double bond that allows further functionalization on their structure. In an attempt to expand the number of derivatives of these two natural products, we have undertaken a study on the hydroformylation of the methyl esters of the two acids and the trimethy...
Synthesis of amphiphilic sulfonamide halogenated porphyrins: MALDI-TOFMS charac...
Monteiro, Carlos J. P.; Pereira, Mariette M.; Pinto, Sara M. A.; Simões, Ana V. C.; Sá, Gonçalo F. F.; Arnaut, Luís G.; Formosinho, Sebastião J.Porphyrins are key precursors for development of photosensitizers for photodynamic therapy. A new series of ortho-halogenated tetraarylporphyrins with sulfonamide substituents have been synthesized via chlorosulfonation reaction and characterized by MALDI-TOFMS. To predict their partition properties, log KOW of a selected range of the synthesized halogenated amphiphilic porphyrins is described. A significant ef...
Photoacoustic Measurement of Electron Injection Efficiencies and Energies from ...
Serpa, Carlos; Schabauer, Johann; Piedade, Ana P.; Monteiro, Carlos J. P.; Pereira, Mariette M.; Douglas, Peter; Burrows, Hugh D.; Arnaut, Luís G.Time-resolved photoacoustic calorimetry is used to measure the energy released upon injection of an electron from an electronically excited dye adsorbed to nanocrystalline TiO2 into the conduction band of this material. More energy is released when the environment of the dye is made less polar, because the energy of the dye-oxidized state has a more pronounced solvent dependence than the edge of the conduction ...
A comparative study of water soluble 5,10,15,20-tetrakis(2,6-dichloro-3-sulfoph...
Monteiro, Carlos J. P.; Pereira, Mariette M.; Azenha, M. Emilia; Burrows, Hugh D.; Serpa, Carlos; Arnaut, Luís G.; Tapia, M. J.; Sarakha, Mohamed5,10,15,20-Tetrakis(2,6-dichloro-3-chlorosulfophenyl)porphyrin and its tin and zinc complexes were synthesized with high yields and fully characterized. The corresponding water-soluble 5,10,15,20-tetrakis(2,6-dichloro-3-sulfophenyl)porphyrins were obtained by hydrolysis with water. An extensive photophysical study of the new water soluble porphyrinic compounds was carried out including absorption and fluorescen...
Oxidation of Δ4- and Δ5-Steroids with Hydrogen Peroxide Catalyzed by Porphyrin ...
Rebelo, Susana L. H.; Simões, Mário M. Q.; Neves, M. Graça P. M. S.; Silva, Artur M. S.; Cavaleiro, José A. S.; Peixoto, Andreia F.In this paper we describe a new environmentally friendly method to promote the stereoselective epoxidation of Delta4- and Delta5-steroids. Metalloporphyrins efficiently catalyze the epoxidation reactions of 17beta-acetoxy-4-androstene (1), 4-cholestene (2) and 3beta-acetoxy-5-cholestene (3) in the presence of H2O2 as oxygen donor. Modeling the molecular structure of the porphyrin as well as the central metal al...
Photooxidation of 4-chlorophenol sensitised by iron meso-tetrakis(2,6-dichloro-...
Silva, Eliana; Pereira, Mariette M.; Burrows, Hugh D.; Azenha, M. E.; Sarakha, Mohamed; Bolte, MichèleThe photosensitised degradation of 4-chlorophenol (4-CP) by iron meso-tetrakis(2,6-dichloro-3-sulfophenyl)porphyrin (FeTDCPPS) has been studied in aerated aqueous solution, and is shown to lead to formation of p-benzoquinone (BQ) and p-hydroquinone (HQ) as main photoproducts. In deaerated solution no p-benzoquinone was formed. The photolysis products were identified by high performance liquid chromatography (HP...
Heavy-atom effects on metalloporphyrins and polyhalogenated porphyrins
Azenha, Emília G.; Serra, Arménio C.; Pineiro, Marta; Pereira, Mariette M.; Seixas de Melo, J.; Arnaut, Luis G.; Formosinho, Sebastião J.http://www.sciencedirect.com/science/article/B6TFM-45PTWJX-J/1/69780b458d5289db997df5735c97350c
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