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New iron nanofertilizers to amend chlorosis in soybean plants

Moniz, Tânia; Pinho, Simão; Santos, Carla; Granja, Andreia; Vasconcelos, Marta; Castro, Baltazar de; Rangel, Maria; Reis, Salette


New hydrophilic 3-hydroxy-4-pyridinone chelators with ether-derived substituent...

Moniz, Tânia; Cunha-Silva, Luís; Mesquita, Raquel B.R.; Miranda, Joana L.A.; Silva, André M.N.; Silva, Ana M.G.; Rangel, António O.S.S.

Three new hydrophilic 3-hydroxy-4-pyridinone chelators containing ether-derived substituents were prepared by a more sustainable synthetic protocol that involves the use of microwave heating and commercially available amines, allowing the successful production of highly water soluble chelators with improved reaction yields and reaction times. Compared with parent 3-hydroxy-4-pyridinone ligands, the new compound...


Catalytic oxidative/extractive desulfurization of model and untreated diesel us...

Ribeiro, Susana O.; Julião, Diana; Cunha-Silva, Luís; Domingues, Valentina F.; Valença, Rita; Ribeiro, Jorge C.; Castro, Baltazar de; Balula, Salete S.

The desulfurization efficiency of various hybrid zinc-substituted polyoxometalates ([PW11Zn(H2O)O39]5−, abbreviated as PW11Zn) was here investigated for the first time and optimized using sustainable systems conciliating successfully the liquid–liquid extraction and the oxidative catalytic process. Initially, the desulfurization studies were performed using a model diesel containing a mixture of the most refrac...


Spectroelectrochemical characterisation of copper salen-based polymer modified ...

Martins, Madga; Vilas-Boas, Miguel; Castro, Baltazar de; Hillman, A. Robert; Freire, Cristina

Electrogenerated polymers based on copper salen-type complexes were characterised electrochemically and by in situ UV–vis and ex situ EPR spectroscopy. The films, poly[Cu(salen)] and poly[Cu(saltMe)], exhibit reversible oxidative electrochemical behaviour in a wide potential range (0.0–1.5 V). Different regimes for charge transport behaviour are accessed by manipulation of film thickness and experimental time s...

Date: 2005   |   Origin: Biblioteca Digital do IPB

Copper-containing nitrite reductase from Pseudomonas chlororaphis DSM 50135

Moura, Isabel; Pinho, Dora; Besson, Stéphane; Brondino, Carlos D.; Castro, Baltazar de

Eur. J. Biochem. 271, 2361–2369 (2004); The nitrite reductase (Nir) isolated from Pseudomonas chlororaphis DSM 50135 is a blue enzyme, with type 1 and type 2 copper centers, as in all copper-containing Nirs described so far. For the first time, a direct determination of the reduction potentials of both copper centers in a Cu-Nir was performed: type 2 copper (T2Cu), 172 mV and type 1 copper (T1Cu), 298 mV at pH ...


Spectroelectrochemical characterisation of a poly[Ni(saltMe)] modified electrode

Vilas-Boas, Miguel; Freire, Cristina; Castro, Baltazar de; Christensen, Paul A.; Hillman, A. Robert

Electrogenerated polymers based on the nickel(II) compIex 2,3-dimetbyl- N,N -bis(salicylidene )butane-2,3- diaminatoniekel(II), poly[Ni(saltMe)], were characterized by in situ FTIR and UV/Vis spectroscopy and ex-situ EPR spectroscopy in order to gain insights into film structure, electronic states and charge conduction. The role of the nickel ions during film oxidation was probed by using EPR to study naturally...

Date: 2001   |   Origin: Biblioteca Digital do IPB

Electrochemical and structural studies of nickel (II) Schiff base complexes der...

Santos, Isabel C.; Vilas-Boas, Miguel; Piedade, M.F.M.; Freire, Cristina; Duarte, M.T.; Castro, Baltazar de

The oxidative chemistry of three Ni(II) complexes with Schiff base ligands derived from salicylaldehyde and diamines with different steric demands, N,N9-2-methylpropane-2,3-diyl-bis(salicylideneiminate)nickel(II) (1), N,N9-1,2-cyclohexyl-1,2-dyil-bis(salicylideneiminate)- nickel(II) (2) and N,N9-2,3-dimethylbutane-2,3-diyl-bis(salicylideneiminate)nickel(II) (3), was studied by cyclic voltammetry and chronoamper...

Date: 2000   |   Origin: Biblioteca Digital do IPB

Electrochemical characterization of a novel salen type modified electrode

Vilas-Boas, Miguel; Freire, Cristina; Castro, Baltazar de; Hillman, A. Robert

The nickel(II) complex with H2saltMe, a N2O2 Schiff base ligand derived from salicylaldehyde, was oxidatively electropolymerized on Pt electrodes in CH3CN/0.1 mol dm-3 tetraethylammonium perchlorate (TEAP) to generate polymer films that exhibit reversible oxidative electrochemical behavior in a wide potential range (0.0-1.3 V), high conductivity, and stability/durability.

Date: 1998   |   Origin: Biblioteca Digital do IPB

New Insigths into the structure and properties of electroactive polymer filmes ...

Vilas-Boas, Miguel; Freire, Cristina; Castro, Baltazar de; Christensen, Paul A.; Hillman, A. Robert

Oxidative electrochemical polymerization of (N,N'-ethylenebis(salicylideneaminato)) nickel(II), [Ni(salen)], in acetonitrile/TEAP was reinvestigated. The polymers were characterized by in situ FTIR and UV-visible spectroscopies in order to explore film structure and to clarify the electronic states as a function of the electrochemically controlled applied redox potential; oxidized species involved in polymeriza...

Date: 1997   |   Origin: Biblioteca Digital do IPB

Formation and decomposition study of electrochemically-generated nickel(III)–no...

Castro, Baltazar de; Gomes, João; Marques, M. Paula M.; Geraldes, Carlos F. G. C.


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