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Hannes Neukirch

Bio: Hannes Neukirch is an academic researcher from Polytechnic University of Milan. The author has contributed to research in topics: Halogen bond & Crystal engineering. The author has an hindex of 4, co-authored 6 publications receiving 1943 citations.

Papers
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Journal ArticleDOI
TL;DR: The main features of the interaction are given, and the close similarity with the hydrogen bonding will become apparent, and some heuristic principles are presented to develop a rational crystal engineering based on halogen bonding.
Abstract: Halogen bonding is the noncovalent interaction between halogen atoms (Lewis acids) and neutral or anionic Lewis bases. The main features of the interaction are given, and the close similarity with the hydrogen bonding will become apparent. Some heuristic principles are presented to develop a rational crystal engineering based on halogen bonding. The focus is on halogen-bonded supramolecular architectures given by halocarbons. The potential of the interaction is shown by useful applications in the field of synthetic chemistry, material science, and bioorganic chemistry.

1,673 citations

Journal ArticleDOI
TL;DR: The single-crystal X-ray structure of the complex between the heteroditopic receptor and sodium iodide is reported and, thanks to the cooperativity of metal coordination and the strong I-...I halogen bonding, the ion pair is fully separated.
Abstract: A new heteroditopic receptor for alkali metal halides has been designed and synthesized. It is comprised of a well-established motif for cation binding and a motif for halogen-bonding-based anion recognition processes. The single-crystal X-ray structure of the complex between the heteroditopic receptor and sodium iodide is reported. Thanks to the cooperativity of metal coordination and the strong I-···I halogen bonding, the ion pair is fully separated. The boosting effect of the binding of the anion through halogen bonding on the coordination of the cation by the receptor has been proved also in solution by NMR experiments. The selectivity of the new heterotopic receptor toward different alkali metal halides has been tested by ESI mass experiments.

229 citations

Journal ArticleDOI
TL;DR: In this paper, the supramolecular organization in six solid assemblies involving iodo-and bromoperfluoroarene derivatives is described and single crystal X-ray analyses are performed.

61 citations

Journal ArticleDOI
TL;DR: The halogen bonding driven self-assembly of 1,8-diiodoperfluorooctane and N,N,N',N'-tetramethyl-p-phenylenediamine induces the formation of a chiral and enantiopure co-crystal wherein the fluorinated chains adopt an unusual gauche arrangement.

35 citations

Journal ArticleDOI
TL;DR: In this article, the main features of the interaction are given, and the close similarity with the hydrogen bonding will become apparent, and some heuristic principles are presented to develop a rational crystal engineering based on halogen bonding.
Abstract: Halogen bonding is the noncovalent interaction between halogen atoms (Lewis acids) and neutral or anionic Lewis bases. The main features of the interaction are given, and the close similarity with the hydrogen bonding will become apparent. Some heuristic principles are presented to develop a rational crystal engineering based on halogen bonding. The focus is on halogen-bonded supramolecular architectures given by halocarbons. The potential of the interaction is shown by useful applications in the field of synthetic chemistry, material science, and bioorganic chemistry.

1 citations


Cited by
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Journal ArticleDOI
10 Mar 1970

8,159 citations

Journal ArticleDOI
TL;DR: 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.
Abstract: 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.

2,582 citations

Journal ArticleDOI
TL;DR: In this paper, the authors carried out a natural bond order B3LYP analysis of the molecules CF(3)X, with X = F, Cl, Br and I. The results showed that the Cl and Br atoms in these molecules closely approximate the [Formula: see text] configuration, where the z-axis is along the R-X bond.
Abstract: Halogen bonding refers to the non-covalent interactions of halogen atoms X in some molecules, RX, with negative sites on others. It can be explained by the presence of a region of positive electrostatic potential, the sigma-hole, on the outermost portion of the halogen's surface, centered on the R-X axis. We have carried out a natural bond order B3LYP analysis of the molecules CF(3)X, with X = F, Cl, Br and I. It shows that the Cl, Br and I atoms in these molecules closely approximate the [Formula: see text] configuration, where the z-axis is along the R-X bond. The three unshared pairs of electrons produce a belt of negative electrostatic potential around the central part of X, leaving the outermost region positive, the sigma-hole. This is not found in the case of fluorine, for which the combination of its high electronegativity plus significant sp-hybridization causes an influx of electronic charge that neutralizes the sigma-hole. These factors become progressively less important in proceeding to Cl, Br and I, and their effects are also counteracted by the presence of electron-withdrawing substituents in the remainder of the molecule. Thus a sigma-hole is observed for the Cl in CF(3)Cl, but not in CH(3)Cl.

1,893 citations

Journal ArticleDOI
TL;DR: In this article, the energy and geometrical features of the interaction are described along with the atomic characteristics that confer molecules with the specific ability to interact through this interaction, and some principles are presented for crystal engineering based on halogen-bonding interactions.
Abstract: Halogen bonding is the noncovalent interaction where halogen atoms function as electrophilic species. The energetic and geometrical features of the interaction are described along with the atomic characteristics that confer molecules with the specific ability to interact through this interaction. Halogen bonding has an impact on all research fields where the control of intermolecular recognition and self-assembly processes plays a key role. Some principles are presented for crystal engineering based on halogen-bonding interactions. The potential of the interaction is also shown by applications in liquid crystals, magnetic and conducting materials, and biological systems.

1,358 citations

Journal ArticleDOI
TL;DR: Experimental as well as computational studies indicate that halogen and other sigma-hole interactions can be competitive with hydrogen bonding, which itself can be viewed as a subset of s Sigma-hole bonding.
Abstract: A halogen bond is a highly directional, electrostatically-driven noncovalent interaction between a region of positive electrostatic potential on the outer side of the halogen X in a molecule R–X and a negative site B, such as a lone pair of a Lewis base or the π-electrons of an unsaturated system. The positive region on X corresponds to the electronically-depleted outer lobe of the half-filled p-type orbital of X that is involved in forming the covalent bond to R. This depletion is labeled a σ-hole. The resulting positive electrostatic potential is along the extension of the R–X bond, which accounts for the directionality of halogen bonding. Positive σ-holes can also be found on covalently-bonded Group IV–VI atoms, which can similarly interact electrostatically with negative sites. Since positive σ-holes often exist in conjunction with negative potentials on other portions of the atom's surface, such atoms can interact electrostatically with both nucleophiles and electrophiles, as has been observed in surveys of crystallographic structures. Experimental as well as computational studies indicate that halogen and other σ-hole interactions can be competitive with hydrogen bonding, which itself can be viewed as a subset of σ-hole bonding.

1,332 citations