Giuseppe Resnati - Academia.edu (original) (raw)
Papers by Giuseppe Resnati
Acta Crystallographica Section C Crystal Structure Communications, 1999
Encyclopedia of Supramolecular Chemistry, 2004
Chemical Reviews, 2016
The halogen bond occurs when there is evidence of a net attractive interaction between an electro... more The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.
Journal of the American Chemical Society, Jan 19, 2015
A modular molecular kit for the preparation of crystalline molecular rotors was devised from a se... more A modular molecular kit for the preparation of crystalline molecular rotors was devised from a set of stators and rotators to gain simple access to a large number of structures with different dynamic performance and physical properties. In this paper, we have accomplished this with crystalline molecular rotors self-assembled by halogen bonding of di-azabicylo[2.2.2]octane (DABCO), acting as a rotator, and a set of five fluorine-substituted iodobenzenes that take the role of the stator. Using variable temperature 1H T1 spin lattice relaxation measurements, we have shown that all structures display ultrafast Brownian rotation with activation energies ranging from 2.4 to 4.9 kcal/mol and a pre-exponential factors of the order of 1-9 x 1012 s-1. Lineshape analysis of quadrupo-lar echo 2H NMR measurements in selected examples indicated rotational trajectories consistent with the 3-fold or 6 fold symmetric potential of the rotator.
Journal of Molecular Graphics and Modelling, 2016
Hydrophobins are proteins of interest for numerous applications thanks to their unique conformati... more Hydrophobins are proteins of interest for numerous applications thanks to their unique conformational and surface properties and their ability to self-assemble at interfaces. Here we report fully atomistic molecular mechanics and molecular dynamics results together with circular dichroism experimental data, aimed to study the conformational properties of the hydrophobin HFBII in a fluorinated solvent in comparison with a water solution and/or at an aqueous/vacuum interface. Both the atomistic simulations and the circular dichroism data show the remarkable structural stability of HFBII at all scales in all these environments, with no significant structural change, although a small cavity is formed in the fluorinated solvent. The combination of theoretical calculations and circular dichroism data can describe in detail the protein conformation and flexibility in different solvents and/or at an interface, and constitutes a first step towards the study of their self-assembly.
![Research paper thumbnail of Interactions at the Outside Faces of Calix[4]arenes: Two-Dimensional Infinite Network Formation with Perfluoroarenes](https://attachments.academia-assets.com/94755718/thumbnails/1.jpg)
](Chemistry - A European Journal
Attractive p ± p interactions between two of the four outside cavity faces of 1,3-bis-pyridylmeth... more Attractive p ± p interactions between two of the four outside cavity faces of 1,3-bis-pyridylmethylcalix[4]arene (1) and both faces of 1,4-diiodotetrafluorobenzene (2 a) form infinite onedimensional non-covalent ribbons where the two modules alternate. These ribbons are cross-linked by electron donor ± acceptor interactions between picolyl nitrogen atoms of calixarene 1 in one chain and iodine atoms of perfluor-oarene 2 a in another chain and the twodimensional supramolecular network 3 a is formed. A similar behaviour is also shown by 1,4-dibromotetrafluorobenzene (2 b). The halogen bonding and the attractive p ± p interactions occur in directions which are nearly orthogonal each other. Diiodotetrafluorobenzene, being involved in both these interactions, appears to be a particularly interesting tecton. The ability of electronpoor arenes to elicit the exo-receptor potential of calixarene module by connecting their outside faces through p ± p interactions may be developed as a new and general binding protocol in calixarene self-assembly processes.
ChemInform, 2010
Fluorinated Barbituric Acid Derivatives-(I) (evidence of the expected keto structure by X-ray ana... more Fluorinated Barbituric Acid Derivatives-(I) (evidence of the expected keto structure by X-ray analysis).-(DESMARTEAU, D. D.;
Nature Communications, 2015
Amyloid supramolecular assemblies have found widespread exploitation as ordered nanomaterials in ... more Amyloid supramolecular assemblies have found widespread exploitation as ordered nanomaterials in a range of applications from materials science to biotechnology. New strategies are, however, required for understanding and promoting mature fibril formation from simple monomer motifs through easy and scalable processes. Noncovalent interactions are key to forming and holding the amyloid structure together. On the other hand, the halogen bond has never been used purposefully to achieve control over amyloid self-assembly. Here we show that single atom replacement of hydrogen with iodine, a halogen-bond donor, in the human calcitonin-derived amyloidogenic fragment DFNKF results in a super-gelator peptide, which forms a strong and shape-persistent hydrogel at 30-fold lower concentration than the wild-type pentapeptide. This is remarkable for such a modest perturbation in structure. Iodination of aromatic amino acids may thus develop as a general strategy for the design of new hydrogels from unprotected peptides and without using organic solvents.
Angewandte Chemie, 2015
Halogen bonding (XB) is an attractive interaction between electrophilic halogen atoms in organic ... more Halogen bonding (XB) is an attractive interaction between electrophilic halogen atoms in organic halides and Lewis bases, such as amines, ketones, ethers, and nucleophilic anions. [1, 2] This type of interaction has attracted considerable interest, but most studies on XB reported to date have relied solely on solid-state observations [3] or theoretical predictions and interpretations. [4] Although they also exist in solution, halogen-bonded systems in liquid media have received much less attention. [5-7] Previously,the self-assembled cage 1 (Figure 1) was shown to accommodate molecular aggregates, such as DNA duplexes [8] and fluorous aggregates. [9] In the confined space of 1,weak interactions within the aggregates are enhanced, as observed by both NMR spectroscopy and X-ray crystallography.The solution structures (NMR) were consistently the same as the solid-state structures (X-ray). In this study,we investigated halogen-bonded systems in the cavity of cage 1. We observed clear XB between iodoperfluorocarbons 2 and 3 (XB donors) and NO 3 À anions and/or H 2 Omolecules (XB acceptors). Both NMR spectroscopic and X-ray crystallographic studies suggested that XB assists guest inclusion. We also observed the pair-selective inclusion of an aromatic
Coordination Chemistry Reviews, 2010
Halogen bonding (XB) has been recently exploited as a significant tool for engineering crystals i... more Halogen bonding (XB) has been recently exploited as a significant tool for engineering crystals involving coordination and organometallic compounds as tectons. This review, in particular, focuses on extended networks based on XB between electron donor groups bound to metals and halo-pyridine and halo-tetrathiafulvalene moieties as electron acceptors. The influence of XB over the structures and the interactions between the organic
Topics in Current Chemistry, 2014
Halogen bonding (XB) is among the most recent and the least exploited non-covalent interactions i... more Halogen bonding (XB) is among the most recent and the least exploited non-covalent interactions in the toolbox of supramolecular sciences. It can be defined as an attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same molecular entity [1]. Most of the properties of the halogen bond, such as directionality, strength, and tunability, can be rationalized by considering the interaction as essentially electrostatic. Electrostatic forces give rise to an electropositive area on the surface of the halogen-bond donor atom, narrowly located on the extension of the R-X bond and called a σhole [2]. Due to this region, an electron donor (e.g., a Lewis base) will be attracted by the σ-hole and depleted by the rest of the atom surface. This explains the high directionality and linearity of halogen-bonded structures, both in the gas phase [3] and in the solid state [4]. The strength of the halogen bonding can be adjusted by tuning the polarizability of the halogen atom: the higher the polarizability, the greater the interaction strength. Also increasing the electron-withdrawing capability of the moiety to which the XB-donor is attached can increase the interaction strength. Within the past decade, halogen bonding has emerged as a first-class tool in fields as diverse as supramolecular chemistry [5], medicinal chemistry [6], crystal engineering [7], biochemistry [8], and materials science [9,10]. The present work is focused on a specific subset of the latter where halogen bonding seems particularly promising, namely photoresponsive azobenzene-containing materials. The first reports on halogen-bonded photoresponsive polymers and liquid crystals appeared as recently as in 2012 [11, 12]. The field is still in its infancy, but nonetheless highly potential and multifaceted, as highlighted by the examples given herein. The remainder of this review comprises a general introduction to azobenzene, the key photoactive unit of the studies presented. Subsequently, we will bring out the recent advances in halogen-bonded photoactive polymers, liquid crystals, and crystals, respectively, before concluding with some future perspectives.
Journal of the Chemical Society, Chemical Communications, 1995
Perfluoro-cis-2,3-dialkyloxaziridines 1 perform the direct epoxidation of glycals 2 to give clean... more Perfluoro-cis-2,3-dialkyloxaziridines 1 perform the direct epoxidation of glycals 2 to give cleanly corresponding 1,2-anhydrosugars 3 with medium to complete diastereoselection; elaboration of these glycals to glycosyl fluorides and lipid conjugates is also reported.
Journal of the Chemical Society, Perkin Transactions 1, 1996
... Chem. Soc., 1979, 101, 6671 Article CAS ; Y. Hata and M. Watanabe, J. Org. Chem., 1981, 46, 6... more ... Chem. Soc., 1979, 101, 6671 Article CAS ; Y. Hata and M. Watanabe, J. Org. Chem., 1981, 46, 610 Article CAS . 30, J. Vidal, L. Guy, S. Stérin and A. Collet, J. Org. Chem., 1993, 58, 4791 Article CAS ; J. Vidal, J. Drouin and A. Collet, J. Chem. Soc., Chem. ...
Tetrahedron Letters, 1996
Several microorganisms have been employed in the reduction of two α,α,α-trifluoro-α′-sulfenylketo... more Several microorganisms have been employed in the reduction of two α,α,α-trifluoro-α′-sulfenylketones. Some of them produce corresponding alcohols in high diastero- and enantioselection, the high conversion in a single enantiomer being secured by the racemization of starting ketones in the biotransformation conditions. Transformation of obtained sulfenyl-trifluoromethyl-alcohols into trifluoromethyl-epoxides is also described.
Journal of the Chemical Society, Perkin Transactions 1, 1989
ABSTRACT
Nature Communications, 2014
Aligning polymeric nanostructures up to macroscale in facile ways remains a challenge in material... more Aligning polymeric nanostructures up to macroscale in facile ways remains a challenge in materials science and technology. Here we show polymeric self-assemblies where nanoscale organization guides the macroscopic alignment up to millimetre scale. The concept is shown by halogen bonding mesogenic 1-iodoperfluoroalkanes to a star-shaped ethyleneglycol-based polymer, having chloride end-groups. The mesogens segregate and stack parallel into aligned domains. This leads to layers at B10 nm periodicity. Combination of directionality of halogen bonding, mesogen parallel stacking and minimization of interfacial curvature translates into an overall alignment in bulk and films up to millimetre scale. Upon heating, novel supramolecular halogen-bonded polymeric liquid crystallinity is also shown. As many polymers present sites capable of receiving halogen bonding, we suggest generic potential of this strategy for aligning polymer self-assemblies.
CrystEngComm, 2014
N-Methylacetamide, a well-known peptide bond model, and dihalotetrafluorobenzenes form co-crystal... more N-Methylacetamide, a well-known peptide bond model, and dihalotetrafluorobenzenes form co-crystals and show geometrically orthogonal hydrogen and halogen bonds sharing the same carbonyl oxygen atom.
Acta Crystallographica Section C Crystal Structure Communications, 1999
Encyclopedia of Supramolecular Chemistry, 2004
Chemical Reviews, 2016
The halogen bond occurs when there is evidence of a net attractive interaction between an electro... more The halogen bond occurs when there is evidence of a net attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same, molecular entity. In this fairly extensive review, after a brief history of the interaction, we will provide the reader with a snapshot of where the research on the halogen bond is now, and, perhaps, where it is going. The specific advantages brought up by a design based on the use of the halogen bond will be demonstrated in quite different fields spanning from material sciences to biomolecular recognition and drug design.
Journal of the American Chemical Society, Jan 19, 2015
A modular molecular kit for the preparation of crystalline molecular rotors was devised from a se... more A modular molecular kit for the preparation of crystalline molecular rotors was devised from a set of stators and rotators to gain simple access to a large number of structures with different dynamic performance and physical properties. In this paper, we have accomplished this with crystalline molecular rotors self-assembled by halogen bonding of di-azabicylo[2.2.2]octane (DABCO), acting as a rotator, and a set of five fluorine-substituted iodobenzenes that take the role of the stator. Using variable temperature 1H T1 spin lattice relaxation measurements, we have shown that all structures display ultrafast Brownian rotation with activation energies ranging from 2.4 to 4.9 kcal/mol and a pre-exponential factors of the order of 1-9 x 1012 s-1. Lineshape analysis of quadrupo-lar echo 2H NMR measurements in selected examples indicated rotational trajectories consistent with the 3-fold or 6 fold symmetric potential of the rotator.
Journal of Molecular Graphics and Modelling, 2016
Hydrophobins are proteins of interest for numerous applications thanks to their unique conformati... more Hydrophobins are proteins of interest for numerous applications thanks to their unique conformational and surface properties and their ability to self-assemble at interfaces. Here we report fully atomistic molecular mechanics and molecular dynamics results together with circular dichroism experimental data, aimed to study the conformational properties of the hydrophobin HFBII in a fluorinated solvent in comparison with a water solution and/or at an aqueous/vacuum interface. Both the atomistic simulations and the circular dichroism data show the remarkable structural stability of HFBII at all scales in all these environments, with no significant structural change, although a small cavity is formed in the fluorinated solvent. The combination of theoretical calculations and circular dichroism data can describe in detail the protein conformation and flexibility in different solvents and/or at an interface, and constitutes a first step towards the study of their self-assembly.
Chemistry - A European Journal
Attractive p ± p interactions between two of the four outside cavity faces of 1,3-bis-pyridylmeth... more Attractive p ± p interactions between two of the four outside cavity faces of 1,3-bis-pyridylmethylcalix[4]arene (1) and both faces of 1,4-diiodotetrafluorobenzene (2 a) form infinite onedimensional non-covalent ribbons where the two modules alternate. These ribbons are cross-linked by electron donor ± acceptor interactions between picolyl nitrogen atoms of calixarene 1 in one chain and iodine atoms of perfluor-oarene 2 a in another chain and the twodimensional supramolecular network 3 a is formed. A similar behaviour is also shown by 1,4-dibromotetrafluorobenzene (2 b). The halogen bonding and the attractive p ± p interactions occur in directions which are nearly orthogonal each other. Diiodotetrafluorobenzene, being involved in both these interactions, appears to be a particularly interesting tecton. The ability of electronpoor arenes to elicit the exo-receptor potential of calixarene module by connecting their outside faces through p ± p interactions may be developed as a new and general binding protocol in calixarene self-assembly processes.
ChemInform, 2010
Fluorinated Barbituric Acid Derivatives-(I) (evidence of the expected keto structure by X-ray ana... more Fluorinated Barbituric Acid Derivatives-(I) (evidence of the expected keto structure by X-ray analysis).-(DESMARTEAU, D. D.;
Nature Communications, 2015
Amyloid supramolecular assemblies have found widespread exploitation as ordered nanomaterials in ... more Amyloid supramolecular assemblies have found widespread exploitation as ordered nanomaterials in a range of applications from materials science to biotechnology. New strategies are, however, required for understanding and promoting mature fibril formation from simple monomer motifs through easy and scalable processes. Noncovalent interactions are key to forming and holding the amyloid structure together. On the other hand, the halogen bond has never been used purposefully to achieve control over amyloid self-assembly. Here we show that single atom replacement of hydrogen with iodine, a halogen-bond donor, in the human calcitonin-derived amyloidogenic fragment DFNKF results in a super-gelator peptide, which forms a strong and shape-persistent hydrogel at 30-fold lower concentration than the wild-type pentapeptide. This is remarkable for such a modest perturbation in structure. Iodination of aromatic amino acids may thus develop as a general strategy for the design of new hydrogels from unprotected peptides and without using organic solvents.
Angewandte Chemie, 2015
Halogen bonding (XB) is an attractive interaction between electrophilic halogen atoms in organic ... more Halogen bonding (XB) is an attractive interaction between electrophilic halogen atoms in organic halides and Lewis bases, such as amines, ketones, ethers, and nucleophilic anions. [1, 2] This type of interaction has attracted considerable interest, but most studies on XB reported to date have relied solely on solid-state observations [3] or theoretical predictions and interpretations. [4] Although they also exist in solution, halogen-bonded systems in liquid media have received much less attention. [5-7] Previously,the self-assembled cage 1 (Figure 1) was shown to accommodate molecular aggregates, such as DNA duplexes [8] and fluorous aggregates. [9] In the confined space of 1,weak interactions within the aggregates are enhanced, as observed by both NMR spectroscopy and X-ray crystallography.The solution structures (NMR) were consistently the same as the solid-state structures (X-ray). In this study,we investigated halogen-bonded systems in the cavity of cage 1. We observed clear XB between iodoperfluorocarbons 2 and 3 (XB donors) and NO 3 À anions and/or H 2 Omolecules (XB acceptors). Both NMR spectroscopic and X-ray crystallographic studies suggested that XB assists guest inclusion. We also observed the pair-selective inclusion of an aromatic
Coordination Chemistry Reviews, 2010
Halogen bonding (XB) has been recently exploited as a significant tool for engineering crystals i... more Halogen bonding (XB) has been recently exploited as a significant tool for engineering crystals involving coordination and organometallic compounds as tectons. This review, in particular, focuses on extended networks based on XB between electron donor groups bound to metals and halo-pyridine and halo-tetrathiafulvalene moieties as electron acceptors. The influence of XB over the structures and the interactions between the organic
Topics in Current Chemistry, 2014
Halogen bonding (XB) is among the most recent and the least exploited non-covalent interactions i... more Halogen bonding (XB) is among the most recent and the least exploited non-covalent interactions in the toolbox of supramolecular sciences. It can be defined as an attractive interaction between an electrophilic region associated with a halogen atom in a molecular entity and a nucleophilic region in another, or the same molecular entity [1]. Most of the properties of the halogen bond, such as directionality, strength, and tunability, can be rationalized by considering the interaction as essentially electrostatic. Electrostatic forces give rise to an electropositive area on the surface of the halogen-bond donor atom, narrowly located on the extension of the R-X bond and called a σhole [2]. Due to this region, an electron donor (e.g., a Lewis base) will be attracted by the σ-hole and depleted by the rest of the atom surface. This explains the high directionality and linearity of halogen-bonded structures, both in the gas phase [3] and in the solid state [4]. The strength of the halogen bonding can be adjusted by tuning the polarizability of the halogen atom: the higher the polarizability, the greater the interaction strength. Also increasing the electron-withdrawing capability of the moiety to which the XB-donor is attached can increase the interaction strength. Within the past decade, halogen bonding has emerged as a first-class tool in fields as diverse as supramolecular chemistry [5], medicinal chemistry [6], crystal engineering [7], biochemistry [8], and materials science [9,10]. The present work is focused on a specific subset of the latter where halogen bonding seems particularly promising, namely photoresponsive azobenzene-containing materials. The first reports on halogen-bonded photoresponsive polymers and liquid crystals appeared as recently as in 2012 [11, 12]. The field is still in its infancy, but nonetheless highly potential and multifaceted, as highlighted by the examples given herein. The remainder of this review comprises a general introduction to azobenzene, the key photoactive unit of the studies presented. Subsequently, we will bring out the recent advances in halogen-bonded photoactive polymers, liquid crystals, and crystals, respectively, before concluding with some future perspectives.
Journal of the Chemical Society, Chemical Communications, 1995
Perfluoro-cis-2,3-dialkyloxaziridines 1 perform the direct epoxidation of glycals 2 to give clean... more Perfluoro-cis-2,3-dialkyloxaziridines 1 perform the direct epoxidation of glycals 2 to give cleanly corresponding 1,2-anhydrosugars 3 with medium to complete diastereoselection; elaboration of these glycals to glycosyl fluorides and lipid conjugates is also reported.
Journal of the Chemical Society, Perkin Transactions 1, 1996
... Chem. Soc., 1979, 101, 6671 Article CAS ; Y. Hata and M. Watanabe, J. Org. Chem., 1981, 46, 6... more ... Chem. Soc., 1979, 101, 6671 Article CAS ; Y. Hata and M. Watanabe, J. Org. Chem., 1981, 46, 610 Article CAS . 30, J. Vidal, L. Guy, S. Stérin and A. Collet, J. Org. Chem., 1993, 58, 4791 Article CAS ; J. Vidal, J. Drouin and A. Collet, J. Chem. Soc., Chem. ...
Tetrahedron Letters, 1996
Several microorganisms have been employed in the reduction of two α,α,α-trifluoro-α′-sulfenylketo... more Several microorganisms have been employed in the reduction of two α,α,α-trifluoro-α′-sulfenylketones. Some of them produce corresponding alcohols in high diastero- and enantioselection, the high conversion in a single enantiomer being secured by the racemization of starting ketones in the biotransformation conditions. Transformation of obtained sulfenyl-trifluoromethyl-alcohols into trifluoromethyl-epoxides is also described.
Journal of the Chemical Society, Perkin Transactions 1, 1989
ABSTRACT
Nature Communications, 2014
Aligning polymeric nanostructures up to macroscale in facile ways remains a challenge in material... more Aligning polymeric nanostructures up to macroscale in facile ways remains a challenge in materials science and technology. Here we show polymeric self-assemblies where nanoscale organization guides the macroscopic alignment up to millimetre scale. The concept is shown by halogen bonding mesogenic 1-iodoperfluoroalkanes to a star-shaped ethyleneglycol-based polymer, having chloride end-groups. The mesogens segregate and stack parallel into aligned domains. This leads to layers at B10 nm periodicity. Combination of directionality of halogen bonding, mesogen parallel stacking and minimization of interfacial curvature translates into an overall alignment in bulk and films up to millimetre scale. Upon heating, novel supramolecular halogen-bonded polymeric liquid crystallinity is also shown. As many polymers present sites capable of receiving halogen bonding, we suggest generic potential of this strategy for aligning polymer self-assemblies.
CrystEngComm, 2014
N-Methylacetamide, a well-known peptide bond model, and dihalotetrafluorobenzenes form co-crystal... more N-Methylacetamide, a well-known peptide bond model, and dihalotetrafluorobenzenes form co-crystals and show geometrically orthogonal hydrogen and halogen bonds sharing the same carbonyl oxygen atom.