scholarly journals Tautomeric Equilibrium of an Asymmetric β-Diketone in Halogen-Bonded Cocrystals with Perfluorinated Iodobenzenes

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 699
Author(s):  
Valentina Martinez ◽  
Nikola Bedeković ◽  
Vladimir Stilinović ◽  
Dominik Cinčić
Keyword(s):  
Solid State ◽  
Hydrogen Atom ◽  
Crystal Structures ◽  
Crystal Packing ◽  
Halogen Bond ◽  
Tautomeric Equilibrium ◽  
Hydroxyl Group ◽  
Halogen Bonds ◽  
Pyridyl Nitrogen

In order to study the effect of halogen bond on tautomerism in β-diketones in the solid-state, we have prepared a series of cocrystals derived from an asymmetric β-diketone, benzoyl-4-pyridoylmethane (b4pm), as halogen bond acceptor and perfluorinated iodobenzenes: iodopentaflourobenzene (ipfb), 1,2-, 1,3- and 1,4-diiodotetraflorobenzene (12tfib, 13tfib and 14tfib) and 1,3,5-triiodo-2,4,6-trifluorobenzene (135titfb). All five cocrystals are assembled by I···N halogen bonds involving pyridyl nitrogen and iodoperfluorobenzene iodine resulting in 1:1 (four compounds) or 1:2 (one compound) cocrystal stoichiometry. Tautomer of b4pm in which hydrogen atom is adjacent to the pyridyl fragment was found to be more stable in vacuo than tautomer with a benzoyl hydroxyl group. This tautomer is also found to be dominant in the majority of crystal structures, somewhat more abundantly in crystal structures of cocrystals in which additional I···O halogen bond with the benzoyl oxygen has been established. Attempts have also been made to prepare an equivalent series of cocrystals using a closely related asymmetric β-diketone, benzoyl-3-pyridoylmethane (b3pm); however, all attempts were unsuccessful, which is attributed to more effective crystal packing of b3pm isomer compared to b4pm, which reduced the probability of cocrystal formation.

scholarly journals Convenient Access to Functionalized Non-Symmetrical Atropisomeric 4,4′-Bipyridines

Compounds ◽  
2021 ◽  
Vol 1 (2) ◽  
pp. 58-74
Author(s):  
Emmanuel Aubert ◽  
Emmanuel Wenger ◽  
Paola Peluso ◽  
Victor Mamane
Keyword(s):  
Solid State ◽  
Intermolecular Interactions ◽  
Medicinal Chemistry ◽  
Crystal Packing ◽  
Cross Coupling ◽  
Coupling Reactions ◽  
Halogen Bonds ◽  
Cross Coupling Reactions ◽  
Cyano Groups ◽  
Post Functionalization

Non-symmetrical chiral 4,4′-bipyridines have recently found interest in organocatalysis and medicinal chemistry. In this regard, the development of efficient methods for their synthesis is highly desirable. Herein, a series of non-symmetrical atropisomeric polyhalogenated 4,4′-bipyridines were prepared and further functionalized by using cross-coupling reactions. The desymmetrization step is based on the N-oxidation of one of the two pyridine rings of the 4,4′-bipyridine skeleton. The main advantage of this methodology is the possible post-functionalization of the pyridine N-oxide, allowing selective introduction of chlorine, bromine or cyano groups in 2- and 2′-postions of the chiral atropisomeric 4,4′-bipyridines. The crystal packing in the solid state of some newly prepared derivatives was analyzed and revealed the importance of halogen bonds in intermolecular interactions.

Intermolecular binding preferences of haloethynyl halogen-bond donors as a function of molecular electrostatic potentials in a family of N-(pyridin-2-yl)amides

2021 ◽  
Author(s):  
Amila M. Abeysekera ◽  
Boris B. Averkiev ◽  
Pierre Le Magueres ◽  
Christer B. Aakeröy
Keyword(s):  
Hydrogen Bonds ◽  
Crystal Structures ◽  
Halogen Bond ◽  
Electrostatic Potentials ◽  
Halogen Bonds ◽  
Molecular Electrostatic Potentials

The roles played by halogen bonds and hydrogen bonds in the crystal structures of N-(pyridin-2-yl)amides were evaluated and rationalised in the context of calculated molecular electrostatic potentials.

scholarly journals Noncovalent Interactions between 1,3,5-Trifluoro-2,4,6-triiodobenzene and a Series of 1,10-Phenanthroline Derivatives: A Combined Theoretical and Experimental Study

Crystals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 140 ◽  
Author(s):  
Yu Zhang ◽  
Jian-Ge Wang ◽  
Weizhou Wang
Keyword(s):  
Crystal Structure ◽  
Crystal Structures ◽  
Quantum Chemical ◽  
Halogen Bond ◽  
Noncovalent Interactions ◽  
Stacking Interactions ◽  
Halogen Bonds ◽  
Π Stacking ◽  
Π Stacking Interaction ◽  
Structural Competition

How many strong C−I⋯N halogen bonds can one 1,3,5-trifluoro-2,4,6-triiodobenzene molecule form in a crystal structure? To answer this question, we investigated in detail the noncovalent interactions between 1,3,5-trifluoro-2,4,6-triiodobenzene and a series of 1,10-phenanthroline derivatives by employing a combined theoretical and experimental method. The results of the quantum chemical calculations and crystallographic experiments clearly show that there is a structural competition between a C−I⋯N halogen bond and π⋯π stacking interaction. For example, when there are much stronger π⋯π stacking interactions between two 1,10-phenanthroline derivative molecules or between two 1,3,5-trifluoro-2,4,6-triiodobenzene molecules in the crystal structures, then one 1,3,5-trifluoro-2,4,6-triiodobenzene molecule forms only one C−I⋯N halogen bond with one 1,10-phenanthroline derivative molecule. Another example is when π⋯π stacking interactions in the crystal structures are not much stronger, one 1,3,5-trifluoro-2,4,6-triiodobenzene molecule can form two C−I⋯N halogen bonds with two 1,10-phenanthroline derivative molecules.

Crystal structure and photoreactivity of a halogen-bonded cocrystal based upon 1,2-diiodoperchlorobenzene and 1,2-bis(pyridin-4-yl)ethylene

2020 ◽  
Vol 76 (6) ◽  
pp. 557-561
Author(s):  
Eric Bosch ◽  
Jessica D. Battle ◽  
Ryan H. Groeneman
Keyword(s):  
Crystal Structure ◽  
Solid State ◽  
Ultraviolet Light ◽  
Halogen Bond ◽  
Cycloaddition Reaction ◽  
Solvent Free ◽  
Halogen Bonds ◽  
Face To Face ◽  
Similar Yield

The formation of a photoreactive cocrystal based upon 1,2-diiodoperchlorobenzene (1,2-C6I2Cl4 ) and trans-1,2-bis(pyridin-4-yl)ethylene (BPE) has been achieved. The resulting cocrystal, 2(1,2-C6I2Cl4 )·(BPE) or C6Cl4I2·0.5C12H10N2, comprises planar sheets of the components held together by the combination of I...N halogen bonds and halogen–halogen contacts. Notably, the 1,2-C6I2Cl4 molecules π-stack in a homogeneous and face-to-face orientation that results in an infinite column of the halogen-bond donor. As a consequence of this stacking arrangement and I...N halogen bonds, molecules of BPE also stack in this type of pattern. In particular, neighbouring ethylene groups in BPE are found to be parallel and within the accepted distance for a photoreaction. Upon exposure to ultraviolet light, the cocrystal undergoes a solid-state [2 + 2] cycloaddition reaction that produces rctt-tetrakis(pyridin-4-yl)cyclobutane (TPCB) with an overall yield of 89%. A solvent-free approach utilizing dry vortex grinding of the components also resulted in a photoreactive material with a similar yield.

Synthesis and Characterisation of Chiral Triazole-Based Halogen-Bond Donors: Halogen Bonds in the Solid State and in Solution

2017 ◽  
Vol 23 (30) ◽  
pp. 7337-7344 ◽  
Author(s):  
Mikk Kaasik ◽  
Sandra Kaabel ◽  
Kadri Kriis ◽  
Ivar Järving ◽  
Riina Aav ◽  
...  
Keyword(s):  
Solid State ◽  
Halogen Bond ◽  
Halogen Bonds

Competition between hydrogen bonds and halogen bonds: a structural study

2018 ◽  
Vol 42 (13) ◽  
pp. 10539-10547 ◽  
Author(s):  
Janaka C. Gamekkanda ◽  
Abhijeet S. Sinha ◽  
John Desper ◽  
Marijana Đaković ◽  
Christer B. Aakeröy
Keyword(s):  
Hydrogen Bond ◽  
Solid State ◽  
Hydrogen Bonds ◽  
Structural Study ◽  
Halogen Bond ◽  
Halogen Bonds ◽  
Hydrogen Bond Donors

O–H hydrogen-bond donors and R–CC–I halogen-bond donors are close competitors for suitable acceptor sites in solid-state assembly.

scholarly journals Anomalous halogen bonds in the crystal structures of 1,2,3-tribromo-5-nitrobenzene and 1,3-dibromo-2-iodo-5-nitrobenzene

2015 ◽  
Vol 71 (8) ◽  
pp. 960-964 ◽  
Author(s):  
José A. Romero ◽  
Gerardo Aguirre Hernández ◽  
Sylvain Bernès
Keyword(s):  
Charge Transfer ◽  
Crystal Structures ◽  
Nitro Group ◽  
Halogen Bond ◽  
Asymmetric Unit ◽  
Halogen Bonds

The title trihalogenated nitrobenzene derivatives, C6H2Br3NO2and C6H2Br2INO2, crystallize in triclinic and monoclinic cells, respectively, with two molecules per asymmetric unit in each case. The asymmetric unit of the tribromo compound features a polarized Brδ+...Brδ-intermolecular halogen bond. After substitution of the Br atom in theparaposition with respect to the nitro group, the network ofX...Xhalogen contacts is reorganized. Two intermolecular polarized halogen bonds are then observed, which present the uncommon polarization Brδ+...Iδ-: the more electronegative site (Br) behaves as a donor and the less electronegative site (I) as an acceptor for the charge transfer.

Halogen bonding directed supramolecular assembly in bromo-substituted trezimides and tennimides

CrystEngComm ◽  
2014 ◽  
Vol 16 (10) ◽  
pp. 1893-1903 ◽  
Author(s):  
Pavle Mocilac ◽  
John F. Gallagher
Keyword(s):  
Hydrogen Bond ◽  
Solid State ◽  
Crystal Structures ◽  
Supramolecular Assembly ◽  
Halogen Bonding ◽  
Strong Hydrogen Bond ◽  
Aggregation Process ◽  
Halogen Bonds ◽  
State Aggregation ◽  
Hydrogen Bond Donors

The imide-based trezimide and tennimide macrocycle crystal structures typically aggregate as 1-D chains through C–Br⋯OC/N/π(arene) halogen bonds (withNc≤ 0.90) that dominate the solid-state aggregation process in the absence of classical strong hydrogen bond donors.

scholarly journals Structural Elucidation of Enantiopure and Racemic 2-Bromo-3-Methylbutyric Acid

Chemistry ◽  
2020 ◽  
Vol 2 (3) ◽  
pp. 691-699
Author(s):  
Rüdiger W. Seidel ◽  
Nils Nöthling ◽  
Richard Goddard ◽  
Christian W. Lehmann
Keyword(s):  
Solid State ◽  
Crystal Structures ◽  
Intermolecular Interactions ◽  
Crystal Packing ◽  
Structural Elucidation ◽  
Monocarboxylic Acids ◽  
Triclinic Crystal System ◽  
X Ray Crystallography ◽  
Methylbutyric Acid ◽  
Solid State Structures

Halogenated carboxylic acids have been important compounds in chemical synthesis and indispensable research tools in biochemical studies for decades. Nevertheless, the number of structurally characterized simple α-brominated monocarboxylic acids is still limited. We herein report the crystallization and structural elucidation of (R)- and rac-2-bromo-3-methylbutyric acid (2-bromo-3-methylbutanoic acid, 1) to shed light on intermolecular interactions, in particular hydrogen bonding motifs, packing modes and preferred conformations in the solid-state. The crystal structures of (R)- and rac-1 are revealed by X-ray crystallography. Both compounds crystallize in the triclinic crystal system with Z = 2; (R)-1 exhibits two crystallographically distinct molecules. In the crystal, (R)-1 forms homochiral O–H···O hydrogen-bonded carboxylic acid dimers with approximate non-crystallographic C2 symmetry. In contrast, rac-1 features centrosymmetric heterochiral dimers with the same carboxy syn···syn homosynthon. The crystal packing of centrosymmetric rac-1 is denser than that of its enantiopure counterpart (R)-1. The molecules in both crystal structures adopt a virtually identical staggered conformation, despite different crystal environments, which indicates a preferred molecular structure of 1. Intermolecular interactions apart from classical O–H···O hydrogen bonds do not appear to have a crucial bearing on the solid-state structures of (R)- and rac-1.

scholarly journals Stoichiomorphic Halogen-Bonded Cocrystals. A Case Study of 1,4-Diiodotetrafluorobenzene and 3-Nitropyridine

2021 ◽  
Author(s):  
Christelle Hajjar ◽  
Tamali Nag ◽  
Hashim Al Sayed ◽  
Jeffrey S. Ovens ◽  
David L. Bryce
Keyword(s):  
Halogen Bond ◽  
Chemical Shifts ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Halogen Bonds ◽  
X Ray Diffraction ◽  
Pyridyl Nitrogen ◽  
Space Group ◽  
X Ray ◽  
Variable Stoichiometry

The concept of variable stoichiometry cocrystallization is explored in halogen-bonded systems. Three novel cocrystals of 1,4-diiodotetrafluorobenzene and 3-nitropyridine with molar ratios of 1:1, 2:1, and 1:2, respectively, are prepared by slow evaporation methods. Single-crystal X-ray diffraction analysis reveals key differences between each of the nominally similar cocrystals. For instance, the 1:1 cocrystal crystallizes in the P21/n space group and features a single chemically and crystallographically unique halogen bond between iodine and the pyridyl nitrogen. The 2:1 cocrystal crystallizes in the P1- space group and features a halogen bond between iodine and one of the nitro oxygens in addition to an iodine-nitrogen halogen bond. The 1:2 cocrystal crystallizes with a large unit cell (V = 9896 Å3) in the Cc space group and features 10 crystallographically distinct iodine-nitrogen halogen bonds. Powder X-ray diffraction experiments carried out on the 1:1 and 2:1 cocrystals confirm that gentle grinding does not alter the crystal forms. 1H → 13C and 19F → 13C cross-polarization magic angle spinning (CP/MAS) NMR experiments performed on powdered samples of the 1:1 and 2:1 cocrystals are used as spectral editing tools to select for either the halogen bond acceptor or donor, respectively. Carbon-13 chemical shifts in the cocrystals are shown to change only very subtly relative to pure solid 1,4-diiodotetrafluorobenzene, but the shift of the carbon directly bonded to iodine nevertheless increases, consistent with halogen bond formation (e.g., a shift of +1.6 ppm for the 2:1 cocrystal). This work contributes new examples to the field of variable stoichiometry cocrystal engineering with halogen bonds.

Sign in / Sign up

Export Citation Format

Share Document