Halogen Bonding: A Paradigm in Supramolecular Chemistry

Metrangolo, Pierangelo; Resnati, Giuseppe

doi:10.1002/1521-3765(20010618)7:12<2511::aid-chem25110>3.0.co;2-t

Cited by 963 publications

(696 citation statements)

References 23 publications

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“…Most likely, Piedford units, a few hydrogen bonds and in particular an enhancement of the Br 3 -synthon by fluorination are responsible for an enhanced stability of Br-3,5-DFPOT. Similar effects have been observed in the case of other fluorinated solids [14]. Interesting inclusion properties of Br-3,5-DFPOT for various large size functional molecules were recently presented [11].…”

Section: Resultssupporting

confidence: 67%

Improved thermal stability of an organic zeolite by fluorination

Reichenbächer

Couderc

Neels

et al. 2007

J Incl Phenom Macrocycl Chem

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The thermal stability of an organic zeolite material, namely 2,4,6-tris(4-bromo-3,5-difluorphenoxy)-1,3,5-triazin (Br-3,5-DFPOT), was improved by fluorination of 2,4,6-tris(4-bromophenoxy)-1,3,5-triazin (BrPOT). The open pore structure (van der Waals diameter of 10.5 Å ) of the modified zeolite was observed up to 110°C in comparison to 70°C for BrPOT. Nitrogen sorption at low temperature showed a type I isotherm and derived pore volumes thereof are in agreement with structural data. It was observed here that Br-3,5-DFPOT crystals preserving the open pore structure could only be obtained below a typical size of about 50 lm. The improved thermal stability of the fluorinated system is attributed to an enhancement of the strength of the Br 3 -synthon.

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Section: Resultssupporting

confidence: 67%

Improved thermal stability of an organic zeolite by fluorination

Reichenbächer

Couderc

Neels

et al. 2007

J Incl Phenom Macrocycl Chem

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“…The elongation effect arises also from major differences existing between the non-conventional C-H···O=C hydrogen bond [49] length (2.343 Å) and the C-Br···O=C halogen bond length (3.060 Å). In fact, this latter distance is 9% shorter than the sum of the van der Waals radii of Br and O [50][51][52], Looking along the b-axis ( Figure 3, top views of the supramolecular walls), there is no significant difference either. The repetitive unit along the c-axis is just a little bit longer in 2 (c = 12.274 Å) by comparison with 1 (c = 11.898 Å).…”

Section: Crystallographic Studiesmentioning

confidence: 93%

“…The elongation effect arises also from major differences existing between the non-conventional C-H¨¨¨O=C hydrogen bond [49] length (2.343 Å) and the C-Br¨¨¨O=C halogen bond length (3.060 Å). In fact, this latter distance is 9% shorter than the sum of the van der Waals radii of Br and O [50][51][52], strongly suggesting that there is more at stake than a simple van der Waals contact between the two heteroatoms. This is also supported by the alignment of the four atoms C-Br¨¨¨O=C matching that of the C-H¨¨¨O=C atoms involved in a hydrogen bond [53].…”

Section: Crystallographic Studiesmentioning

confidence: 99%

Isomorphous Crystals from Diynes and Bromodiynes Involved in Hydrogen and Halogen Bonds

et al. 2016

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Isomorphous crystals of two diacetylene derivatives with carbamate functionality (BocNH-CH 2 -diyne-X, where X = H or Br) have been obtained. The main feature of these structures is the original 2D arrangement (as supramolecular sheets or walls) in which the H bond and halogen bond have a prominent effect on the whole architecture. The two diacetylene compounds harbor neighboring carbamate (Boc protected amine) and conjugated alkyne functionalities. They differ only by the nature of the atom located at the penultimate position of the diyne moiety, either a hydrogen atom or a bromine atom. Both of them adopt very similar 2D wall organizations with antiparallel carbamates (as in antiparallel beta pleated sheets). Additional weak interactions inside the same walls between molecular bricks are H bond interactions (diyne-H¨¨¨O=C) or halogen bond interactions (diyne-Br¨¨¨O=C), respectively. Based on crystallographic atom coordinates, DFT (B3LYP/6-31++G(d,p)) and DFT (M06-2X/6-31++G(d,p)) calculations were performed on these isostructural crystals to gain insight into the intermolecular interactions.

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“…Among different noncovalent interactions, the halogen bond (X-bond) attracts particular attention of researchers because, similarly as the hydrogen bond (H-bond), it is responsible for physical, chemical, and biologic properties of a large group of chemical species [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The X-bond is of the strength close to that of H-bond [1] and is strongly directional [17].…”

Section: Introductionmentioning

confidence: 99%

The shape of the halogen atom—anisotropy of electron distribution and its dependence on basis set and method used

Bankiewicz

Palusiak

2012

Struct Chem

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A search through Crystal Structure Database was performed and the distances in contacts of XÁÁÁN,O, XÁÁÁH(N,O), and XÁÁÁC type were collected together with the information on spatial arrangement of the interacting fragments. A detailed statistical analysis showed that the shape of the halogen atom cannot be simply concluded on the basis of interatomic distances in crystal state although originally the concept of anisotropic charge distribution around halogen nuclei was postulated on the basis of such an analysis. It was proven that the conclusions in that case strongly depend on the type of center interacting with the halogen atom. Therefore, it was postulated that the shape of the halogen atom can be estimated for the unperturbed (due to intermolecular interactions) halogen atom. For this purpose, a method was provided to make possible a numerical quantification of the anisotropy of the halogen atom on the basis of electron density measurements performed within the framework of Atoms in Molecules Quantum Theory. The anisotropy of Cl and Br atoms in H 3 C-X and F 3 C-X (X=Cl, Br) was estimated for MP2 and DFT-B3LYP methods and several different basis sets. The influence of the method and the basis set on the degree of anisotropic distribution of electron density around halogen nuclei was discussed.Keywords Halogen bond Á The shape of the atom Á QTAIM Á DFT Á MP2 Á Basis set

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Halogen Bonding: A Paradigm in Supramolecular Chemistry

Cited by 963 publications

References 23 publications

Improved thermal stability of an organic zeolite by fluorination

Improved thermal stability of an organic zeolite by fluorination

Isomorphous Crystals from Diynes and Bromodiynes Involved in Hydrogen and Halogen Bonds

The shape of the halogen atom—anisotropy of electron distribution and its dependence on basis set and method used

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