Gago, S, Zhang YM, Santos AM, Kohler K, Kuhn FE, Fernandes JA, Pillinger M, Valente AA, Santos TM, Ribeiro-Claro PJA, Goncalves IS.
2004.
Synthesis and characterization of a manganese(II) acetonitrile complex supported on functionalized MCM-41. Microporous and Mesoporous Materials. 76:131-136., Number 1-3
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Gago, S, Fernandes JA, Rainho JP, Ferreira RAS, Pillinger M, Valente AA, Santos TM, Carlos LD, Ribeiro-Claro PJA, Goncalves IS.
2005.
Highly luminescent tris(beta-diketonate)europium(III) complexes immobilized in a functionalized mesoporous silica. Chemistry of Materials. 17:5077-5084., Number 20
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Gago, S, Fonseca IM, Parola AJ.
2013.
Hybrid mesoporous silica grafted with photoisomerizable 2-hydroxychalcones, 2013. Microporous and Mesoporous Materials. 180:40-47.
AbstractHybrid photochromic mesoporous materials based on MCM-41 and SBA-15 were synthesized by covalent attachment of 3'-butoxy-7-hydroxyflavylium (Fl-OH) and 3'-butoxy-7-metoxyflavylium (Fl-OCH3) hydrogensulfates. The pristine materials were initially grafted with 3-chloropropyl groups, reacted with 3'-hydroxyacetophenone and finally condensed with appropriate salicylaldehydes to yield the new hybrids MCM-41-Fl-OH and SBA-15-Fl-OCH3. The materials were characterized by powder X-ray diffraction, N-2 adsorption, solid-state C-13 CPMAS NMR spectroscopy, and thermogravimetric and elemental analyses, which confirm the successful covalent bonding of the flavylium moieties with loadings of 16.90 +/- 0.05% and 11.78 +/- 0.04% (w/w) for MCM-41-Fl-OH and SBA-15-OCH3, respectively. Flavylium compounds originate in solution a multiequilibria reaction network than can be actuated by pH and light, defining pH-coupled photochromic systems. The new hybrids show pH-dependent reflectance spectra resembling those observed in solution, but shifted to higher pH ranges, indicating a higher stability of the grafted flavylium cations. Irradiation of these materials equilibrated at adequate pH values where the photoisomerizable trans-chalcones predominate shows formation of the respective flavylium cations that recover back to the initial compositions upon standing in the dark, leading these new organic-inorganic hybrids as pH-dependent photochromic materials. (C) 2013 Elsevier Inc. All rights reserved.
Gago, S, Gonzalez J, Blasco S, Parola JA, Albelda MT, Garcia-Espana E, Pina F.
2014.
Protonation, coordination chemistry, cyanometallate "supercomplex" formation and fluorescence chemosensing properties of a bis(2,2 '-bipyridino)cyclophane receptor. Dalton Transactions. 43:2437-2447., Number 6
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Gago, S, Petrov V, Diniz AM, Parola AJ, Cunha-Silva L, Pina F.
2012.
Unidirectional Switching between Two Flavylium Reaction Networks by the Action of Alternate Stimuli of Acid and Base, 2012. Journal of Physical Chemistry A. 116:372-380.
AbstractThe introduction of an ester group in the flavylium core allowed the reversible conversion between two different flavylium compounds each one exhibiting its own reaction network. An unidirectional switching cycle between 7-diethylamino-2-(4-(methoxy-carbonyl)phenyl)-1-benzopyrylium and 2-(4-carboxyphenyl)-7-diethylamino-1-benzopyrylium was achieved by means of alternate acid and base stimuli. Addition of base to a methanolic solution of the ester derivative gives rise to the trans-chalcone of the parent carboxylic acid, which upon acidification of the solution forms the respective flavylium cation. This species esterifies under very acidic conditions to restore the original methyl ester derivative. The chemical reaction networks of both compounds were fully characterized from their thermodynamic and kinetic aspects, by a series of pH jumps followed by UV-vis absorption and emission spectroscopy, stopped flow and H-down arrow NMR. The crystal structure of the trans-chalcone of the ester derivative was unveiled showing a supramolecular structure involving hydrogen bonding.
Gago, S, Rodriguez-Borges JE, Teixeira C, Santos AM, Zhao J, Pillinger M, Nunes CD, Petrovski Z, Santos TM, Kuhn FE, Romao CC, Goncalves IS.
2005.
Synthesis, characterization and catalytic studies of bis(chloro)dioxomolybdenum(VI)-chiral diimine complexes. Journal of Molecular Catalysis a-Chemical. 236:1-6., Number 1-2
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Gago, S, Neves P, Monteiro B, Pessego M, Lopes AD, Valente AA, Paz FAA, Pillinger M, Moreira J, Silva CM, Goncalves IS.
2009.
Synthesis and Catalytic Properties in Olefin Epoxidation of Octahedral Dichloridodioxidomolybdenum(VI) Complexes Bearing N,N-Dialkylamide Ligands: Crystal Structure of Mo2O4(mu(2)-O)Cl-2(dmf)(4). European Journal of Inorganic Chemistry. :4528-4537., Number 29-30
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