1,721,038 research outputs found
Halogen bonded Borromean networks by design: topology invariance and metric tuning in a library of multi-component systems
No full textA library of supramolecular anionic networks showing Borromean interpenetration has been prepared by self-assembly of crypt-222, several metal or ammonium halides, and five bis-homologous α,ω-diiodoperfluoroalkanes. Halogen bonding has driven the formation of these anionic networks. Borromean entanglement has been obtained starting from all the four used cations, all the three used anions, but only two of the five used diiodoperfluoroalkanes. As the change of the diiodoperfluoroalkane, the cation, or the anion has a different relative effect on the metrics and bondings of the self-assembled systems, it can be generalized that bonding, namely energetic, features play here a less influential role than metric features in determining the topology of the prepared tetra-component cocrystals. This conclusion may hold true for other multi-component systems and may function as a general heuristic principle when pursuing the preparation of multi-component systems having the same topology but different composition
Metric engineering in hybrid perfluorocarbon-hydrocarbon cocrystals
No full textA small library of 1:1 cocrystals formed on halogen bonding driven self-assembly of α,ω-diiodoperfluoroalkanes with pyridine derivatives is synthesized and characterized through single crystal X-ray analyses. A strict correlation exists between the metrics of the starting tectons and the metrics of the self-assembled architectures. The pitch along the infinite chains, formed on XB driven self-assembly, and the thickness of the fluorocarbon layers, formed due to perfluorocarbon/hydrocarbon segregation, both correlate with the number of difluoromethylene groups in diiodoperfluoroalkanes
FLUO 8-Supramolecular dynamic porous networks resolve mixtures of oligomeric alpha,omega-diiodoperfluoroalkanes in solution and through gas-solid reactions
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The quest for a molecular capsule assembled via halogen bonds
Full text linkA halogen-bonded capsule is obtained via directed assembly of a rigid tetra(3-pyridyl) cavitand and a flexible tetra(4-iodotetrafluorophenyl) calix[4]arene. The pyridyl nitrogen atoms from one cavitand molecule interact with the iodine atoms of a single
calixarene molecule through short and directional I…N halogen bonds. The flexibility of the ethylenedioxy moieties on the calixarene platform results in positional flexibility of the
iodotetrafluorobenzene sites which, coupled with a supramolecular chelating effect, allow for an effective partner-induced geometric fitting between four nitrogen atoms on the cavitand and four iodine atoms on the calixarene
2-(2,3,5,6-Tetrafluoro-4-iodoanilino)ethanol
No full textThe reaction of 2-aminoethanol and iodopentafluorobenzene in the presence of K2CO3 gave the title compound, C8H6F4INO, in high yield. The structure is characterized by double layers of molecules linked by O—H...O and N—H...O hydrogen bonds, and linear C—I...F [I...F = 3.049 (2) Å] and bent C—I...I [I...I = 3.9388 (7) Å] interactions between pairs of nearly parallel iodotetrafluorophenyl groups. No O...I or N...I halogen bonding is found
Halogen and Hydrogen Bonding in Multicomponent Crystals of Tetrabromo-1H-Benzotriazole
Full text link4,5,6,7-Tetrabromo-1H-benzotriazole (TBBT) is still considered a reference inhibitor of casein kinase II (CK2), a valuable target for anticancer therapy, even though the poor solubility in water of this active pharmaceutical ingredient (API) has prevented its implementation in therapy. We decided to explore the interactions preferentially formed by TBBT in crystalline solids in order to obtain information helpful for the development of new TBBT cocrystals possibly endowed with improved bioavailability. In this paper, we describe the synthesis and the structural characterization of the TBBT methanol solvate and of the TBBT salt with N,N,N’,N’-tetramethylethylenediamine. It is shown that TBBT can give rise to several competing interactions. This API is clearly a good halogen bond (XB) donor, with bromine atoms adjacent to the triazole ring possibly better donors than the two others. TBBT is also a good hydrogen bond (HB) donor, with the triazole hydrogen forming an HB with the acceptor or being transferred to it. Interestingly, one of the triazole nitrogens was proven to be able to work as a hydrogen bond acceptor
The Halogen Bond
Full text linkThe 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
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