Dario Pasini | University of Pavia (original) (raw)

Papers by Dario Pasini

Biomaterials Science, 2013

ABSTRACT In this study, we report a facile fabrication of poly(ethylene glycol) (PEG) based bulk ... more ABSTRACT In this study, we report a facile fabrication of poly(ethylene glycol) (PEG) based bulk and micro-patterned hydrogels that are amenable to functionalization with thiol-bearing molecules using the metal-free radical 'thiol-ene' click reaction. The hydrogels were synthesized using photopolymerization of commercially available monomers, namely allyl methacrylate and PEG-methacrylate in the presence of a PEG-dimethacrylate based crosslinker. Swelling behaviour of these hydrogels could be tailored by varying the amount of the hydrophilic monomer in the feed as well as varying the length of the PEG-chain in the methacrylate monomer. Importantly, the extent of functionalization of these hydrogels could be readily tuned by varying the amount of the reactive allyl methacrylate monomer. Analysis of nitrogen content in the hydrogels after conjugation of cysteamine demonstrated that the amount of cysteamine incorporation was in correlation with the amount of allyl groups in the hydrogels. Three-dimensional hydrogel patterns were fabricated using micromolding in capillaries. Tuneable conjugation of a thiol-containing dye molecule and a ligand-mediated immobilization of streptavidin onto these hydrogel patterns were realized. It was found that the swellability of the hydrogel patterns control the diffusion of streptavidin into the interior of the hydrogel matrix. These bio-inert hydrogels could be appended with peptides to promote cellular adhesion. Furthermore, it was demonstrated that the photochemical thiol-ene based method of conjugation enables localized attachment of thiol-containing molecules within these reactive hydrogels.

We describe a macrocyclic chiroptical sensor for the detection of halide anions, with the Binol m... more We describe a macrocyclic chiroptical sensor for the detection of halide anions, with the Binol moiety acting as the CD signalling unit. The macrocycle is conveniently synthesized using CuAAC 'click' reactions in the cyclization step; this methodology installs 1,2,3-triazole moieties within the macrocyclic backbone , able to directionally bind anions by means of CH/X e hydrogen bonds. 1 H NMR complexation studies in CDCl 3 reveal weak binding to halide and aliphatic carboxylate anions. Halide anions, however, when held into the macrocyclic cavity, are able to trigger a large chiroptical response originating from the steric interaction with the Binol moiety, which changes its dihedral angle, thus modulating its characteristic CD signature.

European Journal of Organic Chemistry, 2013

ABSTRACT We describe a novel Binol-containing macrocycle that behaves as a chiroptical probe for ... more ABSTRACT We describe a novel Binol-containing macrocycle that behaves as a chiroptical probe for the detection of biologically relevant ions (Cu2+, Zn2+) under physiological conditions. The macrocycle synthesis is carried out with Binol-based synthons suitably derivatized in the 2,2′- and 3,3′-positions, by means of a room temperature esterification reaction as the cyclization procedure, followed by late-stage unmasking of the four carboxylic acid functionalities embedded within the macrocyclic framework. The recognition events, signaled using both UV and CD spectroscopy, are triggered by macrocyclic rearrangement induced by binding of the cations through coulombic interactions with the carboxylate anions in water at pH 7. The ample CD response ensures high chiroptical sensitivity and demonstrates the feasibility of chiroptical detection of biologically relevant cations by using a non-nitrogen-based ligand under aqueous conditions.

Tetrahedron, 2010

... PDF (411 K); Export citation; E-mail article; Highlight keywords on: No highlighting Reflect ... more ... PDF (411 K); Export citation; E-mail article; Highlight keywords on: No highlighting Reflect Reflect highlight proteins and chemicals NextBio NextBio highlight relevant biomedical terms. Thumbnails - selected | Full-Size images. ...

Beilstein Journal of Organic Chemistry, 2012

We report on the synthesis and characterization of novel shape-persistent, optically active aryla... more We report on the synthesis and characterization of novel shape-persistent, optically active arylamide macrocycles, which can be obtained using a one-pot methodology. Resolved, axially chiral binol scaffolds, which incorporate either methoxy or acetoxy functionalities in the 2,2' positions and carboxylic functionalities in the external 3,3' positions, were used as the source of chirality. Two of these binaphthyls are joined through amidation reactions using rigid diaryl amines of differing shapes, to give homochiral tetraamidic macrocycles. The recognition properties of these supramolecular receptors have been analyzed, and the results indicate a modulation of binding affinities towards dicarboxylate anions, with a drastic change of binding mode depending on the steric and electronic features of the functional groups in the 2,2' positions.

The performance of water-and solvent-cast, two-component photoresist films containing poly(2-isop... more The performance of water-and solvent-cast, two-component photoresist films containing poly(2-isopropenyl-2-oxazoline) or poly(2-isopropenyl-2-oxazoline-costyrene) with a photoacid generator has been investigated. These materials afford negative-tone images after deep-UV exposure and development in a suitable medium (water or toluene). Resist solutions prepared from polymers containing at least 80 mol % 2-isopropenyl-2-oxazoline may be cast from and developed in pure water. Features of higher quality can be obtained when the resist is cast from 2-methoxyethanol, probably because side reactions such as partial hydrolysis of the pendant oxazoline rings in aqueous environments are avoided. It was possible to resolve micrometer scale patterns using ca. 200 mJ/cm 2 of irradiation at 254 nm, followed by heating 2 min at 130°C and development in water alone. Image quality and etch resistance were improved using copolymers containing up to 20 mol % of styrene repeat units.

ACS Symposium Series, 1998

... Jennifer M. Havard1, Dario Pasini1, Jean MJ Fréchet1,3, David Medeiros2, Shintaro Yamada2, an... more ... Jennifer M. Havard1, Dario Pasini1, Jean MJ Fréchet1,3, David Medeiros2, Shintaro Yamada2, and C. Grant Willson2 ... Microcircuit Eng., Grenoble 1982, 82, p. 260. 3. Lin, Q.; Simpson, L.; Steinhausler, T.; Wilder, M.; Willson, CG; Havard, JM; Fréchet, JMJ Proc. ...

An overview of recent advances in the design and the characterization of nanosystems, able to per... more An overview of recent advances in the design and the characterization of nanosystems, able to perform simple logic operations in solution, is reported. Rather than a detailed and comprehensive update for the specialists, this brief review is intended to give the nonspecialists and the readers currently involved on all aspects of nanocomputing a flavor of the challenges and the opportunities presented by designing simple organic molecules or more complex biological systems operating as switches in response to an external stimuli, and, more importantly, operating as "wet" devices capable to perform simple logic operations and computations.

Journal of Photopolymer Science and Technology, 1999

ChemInform, 1992

ABSTRACT The solvent effect on the retro-Diels-Alder (R.D.A.) reaction of 1,4,4a,9a-tetrahydro-4a... more ABSTRACT The solvent effect on the retro-Diels-Alder (R.D.A.) reaction of 1,4,4a,9a-tetrahydro-4a-methyl-(1α,4α,4aα,9aα) -1,4-methanoanthracene-9,10-dione to 2-methyl-1,4-naphthoquinone and cyclopentadiene was investigated kinetically in 16 solvents. The hyperbolic relationship between the kinetic data and the Acceptor Number of the solvent is strong evidence that the solvent acts as an electrophile which lowers the activation energy of the reaction. Furthermore when these rate constants are plotted vs those of the previously investigated Diels-Alder (D.A.) reaction of 1,4-naphthoquinone and 2,3-dimenthylbutadiene, a linear relationships is obtained. The linearity of the graph is a good indication that the nature of the solvent effect is the same in both D.A. and R.D.A. reactions. The above relationships and the thermodynamic parameters strongly suggest that the R.D.A. reaction is a “late transition state” pericyclic reaction whose solvent effect derives from a specific interaction between the solvent and the product.

Journal of Chemistry, 2015

We report on the design and synthesis of new enantiopure binaphthyl derivatives in which electron... more We report on the design and synthesis of new enantiopure binaphthyl derivatives in which electron-donating and electronwithdrawing substituents are placed in direct conjugation, to create push-pull dyes potentially active for NLO applications. The dyes, unprecedentedly, extend their -bridge from the 3,3 positions of the binaphthyl units and incorporate as acceptors 1,3-dicarbonyl and tetrafluorobenzene units, useful for further supramolecular polarization of the chiral dyes.

ACS Symposium Series, 1998

Solid-state luminogens have been subject of great attention since high tech applications of light... more Solid-state luminogens have been subject of great attention since high tech applications of light emitting materials very often require their use in the condensed phase. However, many luminogenic molecules that are highly emissive in dilute solutions, become weakly or even non emissive in the solid state, a phenomenon known as aggregation-caused-quenching (ACQ). Recent works that report luminogens more efficiently emitting in the solid state than in solution, has aroused much interest since the pioneering works of Tang and co-workers who first proposed the concept of aggregation-induced-emission(AIE)[1]: molecules non emissive in solution, show strong light emission in the condensed phase mainly due to a restriction of intramolecular rotation (RIR). Even more interesting is the crystallization-induced-emissive(CIE) behavior characteristic of some non emissive molecules which are induced to emit by crystallization but not amorphization [2]. 4-dimethylamino-2-benzylidene malonic acid ...

Chirality is a powerful tool for the generation of order, directionality, and, as such, of functi... more Chirality is a powerful tool for the generation of order, directionality, and, as such, of function, in assembled nanoscale chemical devices. Axially chiral binaphthyls have been widely used in organic synthesis; the stability of the enantiomers enables their use as robust chirality inducers and catalysts in asymmetric reactions, and they are nowadays industrially applied in a variety of organic transformations. Applications of these compounds in the field of nanosciences are more recent, and not yet fully explored. The integration of such a robust class of chiral compounds, capable of efficient transfer of stereochemical information, into functional aggregates and nanoarchitectures is of great current interest. We will discuss preeminent examples of applications of these synthons in several fields of nanoscience, such as reticular chemistry, non-linear optical materials and imaging, and liquid crystals.

Chirality, 2015

We describe recent advances in chiroptical chemical sensors, in which the design and implementati... more We describe recent advances in chiroptical chemical sensors, in which the design and implementation is based upon the introduction of atropoisomerically chiral moiety within the molecular skeleton. This report include examples of acyclic, macrocyclic, and polymeric receptors that contain this motif. Although the main applications are in the enantioselective sensing of analytes, we report here some cases where the chiral receptors can in fact be used to senseachiral species. Using circular dichroism (CD) spectroscopy as the technique to detect a receptor-analyte interaction, we can distinguish two main sensor categories: that in which the CD signal of a stereolabile, CD-silent probe is activated upon binding, and that in which the signal of a CD-active probe is modulated upon binding. Particular emphasis will be given to cases in which CD spectroscopy is used orthogonally to other means of detection. Chirality 28:116-123, 2016. © 2015 Wiley Periodicals, Inc.

Biomaterials Science, 2013

European Journal of Organic Chemistry, 2013

Tetrahedron, 2010

Beilstein Journal of Organic Chemistry, 2012

ACS Symposium Series, 1998

Journal of Photopolymer Science and Technology, 1999

ChemInform, 1992

Journal of Chemistry, 2015

ACS Symposium Series, 1998

Chirality, 2015