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Félix Sancenón

Publications and source records attributed to Félix Sancenón.

18 recordsLinked to original sources
PubMed2006

The supramolecular chemistry of organic-inorganic hybrid materials.

The combination of nanomaterials as solid supports and supramolecular concepts has led to the development of hybrid materials with improved functionalities. These "hetero-supramolecular" ideas provide a means of bridging the gap between molecular chemistry, materials sciences, and nanotechnology. In recent years, relevant examples have been reported on functional aspects, such as enhanced recognition and sensing by using molecules on preorganized surfaces, the reversible building of nanometer-sized networks and 3D architectures, as well as biomimetic and gated chemistry in hybrid nanomaterials for the development of advanced functional protocols in three-dimensional frameworks. This approach allows the fine-tuning of the properties of nanomaterials and offers new perspectives for the application of supramolecular concepts.

Journal Article↗
PubMed2006

Anchoring dyes into multidimensional large-pore zeolites: a prospective use as chromogenic sensing materials.

A versatile procedure for anchoring dyes into the pores of multidimensional zeolites by including organic dye precursors in the synthesis gel has been developed. To prove the concept, an aniline-functionalised zeolite Beta was obtained by reaction of triethylorthosilicate (TEOS), tetraethylammonium hydroxide, and N-methyl,N-(propyl-3-trimethoxysilyl)aniline (MPTMSA) in the presence of HF. Further extraction of the structure-directing agents resulted in a highly crystalline, white, functionalised zeolite Beta containing anchored aniline groups. Similar organic functionalised molecular sieves (OFMS) have been explored as novel catalysts, but, as far as we know, OFMS have never been used as precursors for dye-immobilisation or to design new solid-based host systems for selective molecular sensing processes as is reported here. In a second step the solids containing dyes were prepared by reaction of the hybrid material with the appropriate reactives to obtain tricyanovinylbenzene, triphenylpyrylium, azoic, and squaraine derivatives. All these reactions are straightforward and involve electrophilic aromatic substitution or diazotisation reactions at the electron-rich aniline ring. The final dye-functionalised solid materials were isolated by simple filtration and washing procedures and have been characterised by a number of techniques. In all cases the Beta structure of the solid remains unaltered. Among the large number of areas where dye-containing zeolites might be of importance, we were interested in testing their unconventional use as heterosupramolecular hosts in chromogenic protocols. To check their potential use as chemosensors, microporous solids with anchored triphenylpyrilium and squaraine dyes were selected and used as sensors for the chromogenic discrimination of amines. It was found that the response of both solids to amines was basically governed by the three-dimensional (3D) solid architecture that tuned the intrinsic unselective reactivity of the pyrylium dye. By using new solid-state supramolecular chemistry protocols we believe that these, and similar future dye-zeolite hosts, might be promising new sensor materials allowing the visible discrimination of selected target guests by size and/or polarity within families or closely related molecules.

Journal Article↗
PubMed2005

Metal-enhanced H-bond donor tendencies of urea and thiourea toward anions: ditopic receptors for silver(I) salts.

The heteroditopic receptors 1 and 2 firmly include an Ag(I) ion into the NS2O2 crown and establish selective H-bond interactions with anions at the covalently linked urea/thiourea (U/T) subunit. Studies in MeCN solution showed that the metal center induces a 10(3)-10(6)-fold enhancement of the anion association constant, due to a coordinative interaction with the O/S atom of the U/T moiety. In the presence of F-, the Ag-O interaction promotes the release of a proton from one of the urea N-H fragments. Ag(I) coordination to the S atom of the thiourea derivative 2 promotes the formation of unusually stable H-bond complexes with Cl- and Br-.

Journal Article↗
PubMed2005

New advances in fluorogenic anion chemosensors.

The development of anion chemosensors is an area of recent interest. We make here a comprehensive review of new advances on anion chemosensing, reported in the literature during the year 2004. The review follows a classification of the sensing systems based on design principles. It comprises: the binding site-signalling subunit approach, the displacement approach and the use of fluoro-chemodosimeters. The first two approximations are based on the use of a suitable anion coordination site coupled with a signalling unit which signals the anion coordination process via changes in its fluorescence behaviour. The two basic subunits are covalently linked in the binding site-signalling subunit approach and not in the displacement approach. In both approaches the fluorescence variation is reversible. The third way to the development of fluorogenic chemosensors is the use of chemodosimeters (also called reagents or reactands) that work usually through irreversible chemical reactions coupled with drastic changes in the fluorescence emission behaviour.

Journal Article↗
PubMed2005

Sesquiterpenes from Centaurea aspera.

The aerial parts of two subspecies of Centaurea aspera L. (Asteraceae) yielded the germacranolides 1a-h, 2, 3, 4 and 5, the elemane derivatives 6d and 6f, the lignan matairesinol, the degraded terpene loliolide, and the onopordopicrin-valine dimeric adduct 7. From these, compounds 1e, 3 and 6d are natural products. The chemical composition of the two subspecies is very similar, a circumstance which does not support a taxonomic subdivision of the species.

Centaurea↗
PubMed2004

Squaraines as fluoro-chromogenic probes for thiol-containing compounds and their application to the detection of biorelevant thiols.

A highly selective colorimetric chemodosimeter for thiol-containing compounds in aqueous solutions is reported. The design protocol makes use of a highly specific reaction between thiols and the electrophilic four-membered ring of highly colored, fluorescent squaraine backbones. At neutral pH selective decoloration and total emission quenching was found due to the rupture of the highly delocalized squaraine framework upon selective nucleophilic addition of thiol-containing derivatives. The squaraine derivatives have been successfully applied to the determination of low-molecular mass aminothiols in human plasma. The method utters the high potential applicability of the chemodosimeter approach in the search for new or improved chromogenic selective or specific probes for target guests.

Animals↗
PubMed2003

A new chromo-chemodosimeter selective for sulfide anion.

A new chromo-chemodosimeter for the anion sulfide in aqueous environments has been developed. The recognition concept is based on a pyrylium-thiopyrylium transformation that is conveniently drawn toward "color chemistry" concepts by means of the anchoring of an aniline group. This causes the color of the aniline-pyrylium backbone in L1 to change selectively from magenta to blue when transformed to the corresponding aniline-thiopyrylium in the presence of the sulfide anion. The method is simple and easy, suggesting potential applications in a variety of different environments where easy and rapid determination of sulfide might be required.

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