Stefano Cicchi | Università degli Studi di Firenze (University of Florence) (original) (raw)
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Papers by Stefano Cicchi
In this work, we present the characterization of an enantiomeric pair of fluorescent dye organoge... more In this work, we present the characterization of an enantiomeric pair of fluorescent dye organogelators and the properties of their stable gel at low concentration in organic solvents. The gels of both enantiomers and of their mixtures were analyzed by differential scanning calorimetry, circular dichroism (CD), atomic force microscopy, UV–vis absorption, and fluorescence.
Method B) Same molar ratio of method A), but performing the reaction under microwave irradiation ... more Method B) Same molar ratio of method A), but performing the reaction under microwave irradiation (nominal power 150 W, nominal temperature 60 C, 20 minutes) and using CuI-P (OEt) 3 as catalyst (0.0269 mmol) and only THF (2ml) as solvent. Same workup procedure using ammonia as for method A).
(3S, 4S)-N-Benzyl-3, 4-dihydroxypyrrolidine 1 has been used as a building block for new enantiopu... more (3S, 4S)-N-Benzyl-3, 4-dihydroxypyrrolidine 1 has been used as a building block for new enantiopure macrocyclic polyesters. Two different synthetic approaches are presented leading to complementary results. The structure of the macrocycles synthesized has been confirmed by NMR spectroscopy and FAB mass spectrometry, and that for dimer 8 has been confirmed by X-ray analysis.
Abstract Enantiopure five-membered ring nitrones derived from L-tartaric acid and from L-malic ac... more Abstract Enantiopure five-membered ring nitrones derived from L-tartaric acid and from L-malic acid undergo highly regio-and stereoselective cycloaddition reactions with an excess of racemic 2, 3-dihydro-1-phenyl-1 H-phospholes producing two readily separable tricyclic cycloadducts and concomitantly effecting kinetic resolution of the dihydrophosphole derivative (diastereomeric ratio up to 10: l; stereoselectivity factor s= kS/kR= 14).
Abstract This contribution is aimed at describing the most recent activity carried out in the lab... more Abstract This contribution is aimed at describing the most recent activity carried out in the labs of ISC-CNR Florence concerning preparation and spectroscopic investigation of two dimensional silver and gold metal nanostructures (metal nanoisland films-MeNIFs), with particular focus on the role played by the morphology of the metal dielectric interfaces on the control and enhancement of the properties of different molecular adsorbates, ie fluorescence emission and Raman response.
Abstract A chiral organogelating scaffold is functionalised with a stable organic radical pendant... more Abstract A chiral organogelating scaffold is functionalised with a stable organic radical pendant. The morphology and spectroscopic properties of the gels are investigated as a function of the organogelator concentration and temperature. The combination of AFM and ESR spectroscopy provides firm evidence that the architecture responsible for the formation of the macroscopic gel (ie, the fibrillar structure) is maintained below the gelling concentration.
Abstract Organic functionalization of carbon nanotube sidewalls is a tool of primary importance i... more Abstract Organic functionalization of carbon nanotube sidewalls is a tool of primary importance in material science and nanotechnology, equally from a fundamental and an applicative point of view.[1, 2] Here, an efficient and versatile approach for the organic/organometallic functionalization of single-walled carbon nanotubes (SWCNTs) capable of imparting multimodality to these fundamental nanostructures, is described.
Several α-spirocyclopropanated heterocyclic ketones were converted to the corresponding cyclopent... more Several α-spirocyclopropanated heterocyclic ketones were converted to the corresponding cyclopentene-anellated heterocycles in moderate to good yields (overall 31-60%) by Wadsworth-Emmons olefination followed by thermal rearrangement of the formed vinylcyclopropanes. In this sequence, the phosphonoacetonitrile was found to be superior to phosphonoacetate in the Wadsworth-Emmons olefinations of tetrahydropyridones.
Abstract The chiral endocyclic enecarbamate 14 has been obtained by deprotonation-elimination fro... more Abstract The chiral endocyclic enecarbamate 14 has been obtained by deprotonation-elimination from the N-Boc pyrrolidine 5 (or its racemic counterpart from 15). Efficiently stereocontrolled epoxidation-methanolysis of 14 afforded α-alkoxy carbamates, which undergo completely stereoselective nucleophilic substitutions to give trisubstituted dihydroxypyrrolidines.
The organic functionalization of either [60] fullerene or MWCNTs with a highly efficient organoge... more The organic functionalization of either [60] fullerene or MWCNTs with a highly efficient organogelator has allowed the production of novel and homogeneously dispersed soft-nanocomposites. While the nanostructured carbon materials produced by simple mixing do not homogeneously disperse into a preformed gel, C60-and MWCNT-containing gels have been conveniently obtained by covalent functionalization of the carbon lattice with reactive organogelator derivatives.
In this work, we present the characterization of an enantiomeric pair of fluorescent dye organoge... more In this work, we present the characterization of an enantiomeric pair of fluorescent dye organogelators and the properties of their stable gel at low concentration in organic solvents. The gels of both enantiomers and of their mixtures were analyzed by differential scanning calorimetry, circular dichroism (CD), atomic force microscopy, UV–vis absorption, and fluorescence.
Method B) Same molar ratio of method A), but performing the reaction under microwave irradiation ... more Method B) Same molar ratio of method A), but performing the reaction under microwave irradiation (nominal power 150 W, nominal temperature 60 C, 20 minutes) and using CuI-P (OEt) 3 as catalyst (0.0269 mmol) and only THF (2ml) as solvent. Same workup procedure using ammonia as for method A).
(3S, 4S)-N-Benzyl-3, 4-dihydroxypyrrolidine 1 has been used as a building block for new enantiopu... more (3S, 4S)-N-Benzyl-3, 4-dihydroxypyrrolidine 1 has been used as a building block for new enantiopure macrocyclic polyesters. Two different synthetic approaches are presented leading to complementary results. The structure of the macrocycles synthesized has been confirmed by NMR spectroscopy and FAB mass spectrometry, and that for dimer 8 has been confirmed by X-ray analysis.
Abstract Enantiopure five-membered ring nitrones derived from L-tartaric acid and from L-malic ac... more Abstract Enantiopure five-membered ring nitrones derived from L-tartaric acid and from L-malic acid undergo highly regio-and stereoselective cycloaddition reactions with an excess of racemic 2, 3-dihydro-1-phenyl-1 H-phospholes producing two readily separable tricyclic cycloadducts and concomitantly effecting kinetic resolution of the dihydrophosphole derivative (diastereomeric ratio up to 10: l; stereoselectivity factor s= kS/kR= 14).
Abstract This contribution is aimed at describing the most recent activity carried out in the lab... more Abstract This contribution is aimed at describing the most recent activity carried out in the labs of ISC-CNR Florence concerning preparation and spectroscopic investigation of two dimensional silver and gold metal nanostructures (metal nanoisland films-MeNIFs), with particular focus on the role played by the morphology of the metal dielectric interfaces on the control and enhancement of the properties of different molecular adsorbates, ie fluorescence emission and Raman response.
Abstract A chiral organogelating scaffold is functionalised with a stable organic radical pendant... more Abstract A chiral organogelating scaffold is functionalised with a stable organic radical pendant. The morphology and spectroscopic properties of the gels are investigated as a function of the organogelator concentration and temperature. The combination of AFM and ESR spectroscopy provides firm evidence that the architecture responsible for the formation of the macroscopic gel (ie, the fibrillar structure) is maintained below the gelling concentration.
Abstract Organic functionalization of carbon nanotube sidewalls is a tool of primary importance i... more Abstract Organic functionalization of carbon nanotube sidewalls is a tool of primary importance in material science and nanotechnology, equally from a fundamental and an applicative point of view.[1, 2] Here, an efficient and versatile approach for the organic/organometallic functionalization of single-walled carbon nanotubes (SWCNTs) capable of imparting multimodality to these fundamental nanostructures, is described.
Several α-spirocyclopropanated heterocyclic ketones were converted to the corresponding cyclopent... more Several α-spirocyclopropanated heterocyclic ketones were converted to the corresponding cyclopentene-anellated heterocycles in moderate to good yields (overall 31-60%) by Wadsworth-Emmons olefination followed by thermal rearrangement of the formed vinylcyclopropanes. In this sequence, the phosphonoacetonitrile was found to be superior to phosphonoacetate in the Wadsworth-Emmons olefinations of tetrahydropyridones.
Abstract The chiral endocyclic enecarbamate 14 has been obtained by deprotonation-elimination fro... more Abstract The chiral endocyclic enecarbamate 14 has been obtained by deprotonation-elimination from the N-Boc pyrrolidine 5 (or its racemic counterpart from 15). Efficiently stereocontrolled epoxidation-methanolysis of 14 afforded α-alkoxy carbamates, which undergo completely stereoselective nucleophilic substitutions to give trisubstituted dihydroxypyrrolidines.
The organic functionalization of either [60] fullerene or MWCNTs with a highly efficient organoge... more The organic functionalization of either [60] fullerene or MWCNTs with a highly efficient organogelator has allowed the production of novel and homogeneously dispersed soft-nanocomposites. While the nanostructured carbon materials produced by simple mixing do not homogeneously disperse into a preformed gel, C60-and MWCNT-containing gels have been conveniently obtained by covalent functionalization of the carbon lattice with reactive organogelator derivatives.