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... 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 (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.... 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 enantiopure macrocyclic polyesters. Two different synthetic approaches are presented leading to complementary results. The structure of the... 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 acid undergo highly regio-and stereoselective cycloaddition reactions with an excess of racemic 2, 3-dihydro-1-phenyl-1 H-phospholes producing... 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 labs of ISC-CNR Florence concerning preparation and spectroscopic investigation of two dimensional silver and gold metal nanostructures (metal... 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. The morphology and spectroscopic properties of the gels are investigated as a function of the organogelator concentration and temperature.... 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 in material science and nanotechnology, equally from a fundamental and an applicative point of view.[1, 2] Here, an efficient and versatile... 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 cyclopentene-anellated heterocycles in moderate to good yields (overall 31-60%) by Wadsworth-Emmons olefination followed by thermal rearrangement of... 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 from the N-Boc pyrrolidine 5 (or its racemic counterpart from 15). Efficiently stereocontrolled epoxidation-methanolysis of 14 afforded α-alkoxy... 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 organogelator has allowed the production of novel and homogeneously dispersed soft-nanocomposites. While the nanostructured carbon materials produced... 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.
The choice of a donor and an acceptor with suitable optical and self-assembly properties is essential in the design of organogel-based light harvesting systems. Organogels can provide supramolecular structures capable of enhancing energy... more
The choice of a donor and an acceptor with suitable optical and self-assembly properties is essential in the design of organogel-based light harvesting systems. Organogels can provide supramolecular structures capable of enhancing energy transfer processes.
A new straightforward and inexpensive one-pot procedure is described for the preparation of enantiopure five-membered cyclic nitrones starting from the corresponding lactols. Its efficiency relies on the condensation of unprotected... more
A new straightforward and inexpensive one-pot procedure is described for the preparation of enantiopure five-membered cyclic nitrones starting from the corresponding lactols. Its efficiency relies on the condensation of unprotected hydroxylamine with readily available lactols and on the chemoselectivity of the subsequent esterification with methanesulfonyl chloride.
Summary Dienes embedded in quinolizidine and indolizidine structures can be prepared in four steps from cyclic nitrones and bicyclopropylidene. The key intermediates α-spirocyclopropanated N-heterocyclic ketones, generated via a domino 1,... more
Summary Dienes embedded in quinolizidine and indolizidine structures can be prepared in four steps from cyclic nitrones and bicyclopropylidene. The key intermediates α-spirocyclopropanated N-heterocyclic ketones, generated via a domino 1, 3-dipolar cycloaddition/thermal rearrangement sequence, were converted by Wittig methylenation to the corresponding vinylcyclopropanes (VCPs), which underwent rearrangement to 1, 3-dienes in the presence of the Wilkinson Rh (I) complex under microwave heating.
Summary The preparation of low-generation dendrimers based on a simple calix [4] arene scaffold by insertion of the iminosugar-analogue C 2-symmetric 3, 4-dihydroxypyrrolidine is described. This methodology allows a rapid incorporation of... more
Summary The preparation of low-generation dendrimers based on a simple calix [4] arene scaffold by insertion of the iminosugar-analogue C 2-symmetric 3, 4-dihydroxypyrrolidine is described. This methodology allows a rapid incorporation of a considerable number of iminosugar-like moieties in a reduced volume and in a well-defined geometry.
The synthesis of two new bicyclic nucleoside analogues is reported. These compounds are iso-homonucleoside and are synthesised through a 1, 3-dipolar cycloaddition of an enantiopure cyclic nitrone to protected allyl acohol and subsequent... more
The synthesis of two new bicyclic nucleoside analogues is reported. These compounds are iso-homonucleoside and are synthesised through a 1, 3-dipolar cycloaddition of an enantiopure cyclic nitrone to protected allyl acohol and subsequent introduction of thymine by a Mitsunobu reaction.
Abstract The synthesis of a new pseudopeptide material based on a chiral pyrrolidine skeleton is described. One of these new compounds interacts, in chloroform solution, selectively with amines. Keywords: Pyrrolidine, molecular... more
Abstract The synthesis of a new pseudopeptide material based on a chiral pyrrolidine skeleton is described. One of these new compounds interacts, in chloroform solution, selectively with amines. Keywords: Pyrrolidine, molecular recognition, amino acid, C3 symmetry
This work reports on the Cu2+ chemosensing behaviour of self-organized micro-array structures of a novel donor–acceptor bichromophoric compound anchored onto Ag nanoisland films. The system exhibits quenching of the fluorescence in the... more
This work reports on the Cu2+ chemosensing behaviour of self-organized micro-array structures of a novel donor–acceptor bichromophoric compound anchored onto Ag nanoisland films. The system exhibits quenching of the fluorescence in the presence of Cu2+ ions, with detection range extending from 2× 10− 8M up to 3× 10− 6M and limit of detection (LOD) of 8× 10− 9M.
Abstract N-benzyl-and N-methyl-N-glycosylhydroxylamines 3a− i were conveniently obtained by reaction of sugars with N-substituted hydroxylamines according to a novel procedure. Subsequent oxidation occurred at the alkyl group, selectively... more
Abstract N-benzyl-and N-methyl-N-glycosylhydroxylamines 3a− i were conveniently obtained by reaction of sugars with N-substituted hydroxylamines according to a novel procedure. Subsequent oxidation occurred at the alkyl group, selectively affording the corresponding C-phenyl-and C-unsubstituted N-glycosylnitrones. C-phenyl-N-glycosylnitrones 10 and 13 underwent highly stereoselective 1, 3-dipolar cycloaddition with dimethyl maleate, with the sugar moiety acting as a chiral auxiliary. Final removal of the ...
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Research Interests: Engineering, Nonlinear Optics, Fluorescence, Biological Sciences, Gold nanoparticle, and 11 moreNitrogen, Luminescence, Optical Properties, Monolayers, CHEMICAL SCIENCES, Optical physics, Infrared, Analytical and Bioanalytical Chemistry, Energy Transfer, Raman Scattering, and Self Assembled Monolayer
Abstract A protocol is presented for a completely enantioselective formal desymmetrization of C s-symmetric diols by monoprotection of the corresponding enantiopure C 2 diols, followed by an inversion of configuration by a Mitsunobu... more
Abstract A protocol is presented for a completely enantioselective formal desymmetrization of C s-symmetric diols by monoprotection of the corresponding enantiopure C 2 diols, followed by an inversion of configuration by a Mitsunobu reaction (“Mitsunobu trick”). Its application to the unprecedented synthesis of enantiopure cis-3, 4-dihydroxypyrroline N-oxides, employed in the enantiodivergent synthesis of two selectively protected 1, 2, 7-trihydroxyindolizidines, is also reported.
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Research Interests:
Multi-walled carbon nanotubes (MWCNTs) were functionalized with a... more
Multi-walled carbon nanotubes (MWCNTs) were functionalized with a bis(2,2':6',2"-terpyridine) ruthenium(ll)-connected diblock poly(N-isopropyacryamide) (RuTpyPNIPAM) by a simple methodology of covalent amidation. The composition and structure of the functionalized ruthenium multi-walled carbon nanotubes (RuMWCNTs) were characterized by thermogravimetric analysis, Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and scanning electron microscopy (SEM). These characterization methods confirm that after functionalization, ruthenium metallopolymer are interconnected or attached as aggregated structures on the surface of the carbon nanotubes.
Research Interests: Engineering, Materials Engineering, Chemistry, Technology, Carbon, and 14 moreCarbon Nanotube, Nanotechnology, Multidisciplinary, Mathematical Sciences, Physical sciences, Macromolecules, CHEMICAL SCIENCES, Particle Size, Oxygen Reduction Reaction, Langmuir, Proton Exchange Membrane Fuel Cell, Industrial Chemistry/Chemical Engineering, Experimental Data, and Nanoscience and nanotechnology
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Abstract The structure and absolute configuration of the predominant of the two diastereomeric 7, 8-di-tert-butoxy-1-phenyloctahydro-1 H-pyrrolo [1, 2-b] phospholo [2, 3-d] isoxazole 1-sulfides obtained in the kinetic resolution... more
Abstract The structure and absolute configuration of the predominant of the two diastereomeric 7, 8-di-tert-butoxy-1-phenyloctahydro-1 H-pyrrolo [1, 2-b] phospholo [2, 3-d] isoxazole 1-sulfides obtained in the kinetic resolution experiment involving cycloaddition reaction of (S, S)-3, 4-di-tert-butoxy-3, 4-dihydro-2 H-pyrrole 1-oxide (1) with an excess of racemic 2, 3-dihydro-1-phenyl-1 H-phosphole 1-sulfide (2), was determined by a single-crystal X-ray diffraction technique. C22H34O3NPS, trigonal, space group P31, a= b= ...
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Abstract The 1, 3-dipolar cycloaddition of nitrones with chiral vinylphosphine oxides or sulfides provides 5-phosphinyl substituted isoxazolidines with selectivity up to 99: 1. Use of chiral nitrones allows a more generalized... more
Abstract The 1, 3-dipolar cycloaddition of nitrones with chiral vinylphosphine oxides or sulfides provides 5-phosphinyl substituted isoxazolidines with selectivity up to 99: 1. Use of chiral nitrones allows a more generalized stereoselective synthesis of these compounds, also by means of a double asymmetric induction. With a racemic phospholene oxide, the high diastereofacial selectivity of the cycloaddition gives rise to a single 4-phosphinyl substituted isoxazolidine from each enantiomer. Moreover, a certain degree of ...
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Research Interests:
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-l-phenyl-1 H-phospholes producing two... more
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-l-phenyl-1 H-phospholes producing two readily separable tricyclic cycloadducts and concomitantly effecting kinetic resolution of the dihydrophosphole derivative. Stereochemistry of the cycloaddition process and scope of the kinetic resolution process have been established in details and adjusted to produce dihydrophosphole derivatives in ...
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Abstract The structure of the major product of the cycloaddition of 2, 2-dimethyl-3, 4-dihydro-2H-pyrrole N-oxide to tert-butyldivinylphosphine sulfide was analyzed by means of single-crystal X-ray diffraction technique. The analysis... more
Abstract The structure of the major product of the cycloaddition of 2, 2-dimethyl-3, 4-dihydro-2H-pyrrole N-oxide to tert-butyldivinylphosphine sulfide was analyzed by means of single-crystal X-ray diffraction technique. The analysis revealed two crystallographically independent molecules that differed in conformation of the fused five-membered heterocyclic rings. These rings were found to be two envelopes in one molecule and two half-chairs in the other. The studied compound was identified as an exo adduct of the expected ...
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Abstract The synthesis of the first and second generation of enantiopure dendrimers based on a chiral trans-3, 4-dihydroxypyrrolidine is reported. Benzenepolycarboxylic acids were used as central nucleus to afford linear and radial... more
Abstract The synthesis of the first and second generation of enantiopure dendrimers based on a chiral trans-3, 4-dihydroxypyrrolidine is reported. Benzenepolycarboxylic acids were used as central nucleus to afford linear and radial growth, and terephthalic acid was used as spacer between the pyrrolidine nuclei. The analysis of the chiroptical properties ([α] D, circular dichroism) of these new dendrimers suggests that those with radial growth present a self organisation of chiral units.
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The 1, 3-dipolar cycloaddition reaction of N-alkyl nitrones with diphenylvinylphosphines affords directly isoxazolidinylphosphines in satisfactory yields and in regio-and stereoselective manner. The parent diphenylvinylphosphine was found... more
The 1, 3-dipolar cycloaddition reaction of N-alkyl nitrones with diphenylvinylphosphines affords directly isoxazolidinylphosphines in satisfactory yields and in regio-and stereoselective manner. The parent diphenylvinylphosphine was found to favor the formation of 5-phosphinoisoxazolidines whereas diphenylpropenylphosphine gave instead the 4-phosphinoisoxazolidine regioisomer. However, in reactions utilizing on alkylarylvinylphosphine and/or N-arylnitrone, oxidation of the phosphine by the nitrone ...
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The synthesis of new organogelators based on a triazine nucleus is described together with the analysis of the properties of the main compound 15. This compound revealed an efficient organogelator in both polar and apolar solvents and... more
The synthesis of new organogelators based on a triazine nucleus is described together with the analysis of the properties of the main compound 15. This compound revealed an efficient organogelator in both polar and apolar solvents and represents a promising precursor of other functionalized organogelators.
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Research Interests:
Abstract The cycloaddition reactions of dimethyl maleate to three functionalized enantiopure pyrroline N-oxides and one related racemic nitrone are reported. The study of the diastereoselectivity in the cycloaddition has been carried out... more
Abstract The cycloaddition reactions of dimethyl maleate to three functionalized enantiopure pyrroline N-oxides and one related racemic nitrone are reported. The study of the diastereoselectivity in the cycloaddition has been carried out by ample variation of the substituents at both the dipole and dipolarophile counterparts. The major cycloadducts, derived from the preferred exo-anti transition states and formed with 62− 90% diastereoselectivity, have been subjected to Mo (CO) 6-induced reductive ring-opening to ...
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An unprecedented functionalization of multi-walled carbon nanotubes (MWCNTs) has been conveniently achieved by the 1,3-dipolar cycloaddition of a cyclic nitrone. This organic functionalization yields materials with a great solubility in... more
An unprecedented functionalization of multi-walled carbon nanotubes (MWCNTs) has been conveniently achieved by the 1,3-dipolar cycloaddition of a cyclic nitrone. This organic functionalization yields materials with a great solubility in DMF (close to 10 mg per mL of DMF) preferentially occurring at the defects of the MWCNT sp(2) network.
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Research Interests:
3. ChemInform Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. ChemInform... more
3. ChemInform Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. ChemInform Abstract
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A new organogelating moiety, 1, is proposed as a suitable and versatile building block for the production of other gelling compounds. Linking 1 with several different molecular fragments afforded new gels with different properties. A... more
A new organogelating moiety, 1, is proposed as a suitable and versatile building block for the production of other gelling compounds. Linking 1 with several different molecular fragments afforded new gels with different properties. A detailed investigation of the ferrocene substituted gelator is reported in this study.