What Is Special about Aromatic–Aromatic Interactions? Significant Attraction at Large Horizontal Displacement

Ninković, Dragan B.; Filipović, Jelena P. Blagojević; Hall, Michael B.; Brothers, Edward N.; Zarić, Snežana D.

doi:10.1021/acscentsci.0c00005

Cited by 51 publications

(54 citation statements)

References 57 publications

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“…However, there is only a modest preference for ac-6 versus sc-6 (0.2-0.6 kcal/mol). As one possible factor, the average arene/arene π contacts [36] in sc-6 are slightly shorter (Figure S4 and Table S2). Also, π interactions are much more pronounced in sc-8 versus ac-8 (Figure S5 and Table S2), accentuating the energy difference.…”

Section: Computational Data: Structure and Bondingmentioning

confidence: 99%

Syntheses, Structures, Reactivities, and Basicities of Quinolinyl and Isoquinolinyl Complexes of an Electron Rich Chiral Rhenium Fragment and Their Electrophilic Addition Products

Molina

Wititsuwannakul

Hampel

et al. 2021

Chemistry A European J

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Reactions of Li + [(η 5 -C 5 H 5 )Re(NO)(PPh 3 )] À with 2and 4-chloroquinoline or 1-chloroisoquinoline give the corresponding σ quinolinyl and isoquinolinyl complexes 3, 6, and 8. With 3 and 8 there is further protonation to yield HCl adducts, but additions of KH give the free bases. Treatment of 3 with HBF 4 •OEt 2 or H(OEt 2 ) 2 + BAr f À gives the quinolinium salts [(η 5 -C 5 H 5 )Re(NO)(PPh 3 )( K C(NH) À ((S Re R C ,R Re S C )-5 + CF 3 SO 3 À , 76 %) in diastereomerically pure form. Crystal structures of 3-H + BAr f À , 3-CH 3 + CF 3 SO 3 À , (S Re R C , R Re S C )-5 + Cl À , and 6-CH 3 + CF 3 SO 3 Àshow that the quinolinium ligands adopt Re•••C conformations that maximize overlap of their acceptor orbitals with the rhenium fragment HOMO, minimize steric interactions with the bulky PPh 3 ligand, and promote various π interactions. NMR experiments establish the Brønsted basicity order 3 > 8 > 6, with K a (BH + ) values > 10 orders of magnitude greater than the parent heterocycles, although they remain less active nucleophilic catalysts in the reactions tested. DFT calculations provide additional insights regarding Re•••C bonding and conformations, basicities, and the stereochemistry of CH 3 Li addition.

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Section: Computational Data: Structure and Bondingmentioning

confidence: 99%

Syntheses, Structures, Reactivities, and Basicities of Quinolinyl and Isoquinolinyl Complexes of an Electron Rich Chiral Rhenium Fragment and Their Electrophilic Addition Products

Molina

Wititsuwannakul

Hampel

et al. 2021

Chemistry A European J

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“…By comparing saturated and unsaturated systems it was shown how the stronger interactions between aromatic molecules are actually due to dispersion and not to any special interactions that necessarily include the π orbitals. In the following years, many structural motifs like π–π interaction and ion‐π interactions have been revisited,[ 16 , 17 , 18 , 19 ] and our view on π interactions is slowly changing towards a more refined description, unravelling the details of dispersion interactions. This inspired us to focus our attention on a prototype system that cannot exhibit “pnictogen‐π” interactions, as it does not contain a π system, in spite of its structural similarity to benzene: cyclohexane.…”

Section: Introductionmentioning

confidence: 99%

Are Heavy Pnictogen‐π Interactions Really “π Interactions”?

Schiavo

Bhattacharyya

Mehring

et al. 2021

Chemistry A European J

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The noncovalent interactions of heavy pnictogens with π‐arenes play a fundamental role in fields like crystal engineering or catalysis. The strength of such bonds is based on an interplay between dispersion and donor/acceptor interactions, and is generally attributed to the presence of π‐arenes. Computational studies of the interaction between the heavy pnictogens As, Sb and Bi and cyclohexane, in comparison with previous studies on the interaction between heavy pnictogens and benzene, show that this concept probably has to be revised. A thorough analysis of all the different energetic components that play a role in these systems, carried out with state‐of‐the‐art computational methods, sheds light on how they influence one another and the effect that their interplay has on the overall system. Furthermore, the analysis of such interactions leads us to the unexpected finding that the presence of the pnictogen compounds strongly affects the conformational equilibrium of cyclohexane, reversing the relative stability of the chair and boat‐twist conformers, and thus suggesting a possible application of tuneable dispersion energy donors to stabilise the desired conformation.

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“…This is a rather long distance for recognizing aromatic-aromatic interactions, but still it matches the established criteria for them (< 7 Å ). In addition, this interaction concerns aromatic rings aligned parallel, and, as was recently shown, a large horizontal distance between interacting aromatic rings may actually be energetically beneficial (Ninković et al, 2020). The molecular conformation of the LIN molecule in this cocrystal is different from any of the conformations found in LIN forms II and III.…”

Section: Lin:ba Cocrystalmentioning

confidence: 73%

Structural variety of heterosynthons in linezolid cocrystals with modified thermal properties

Khalaji

Wróblewska

Wielgus

et al. 2020

Acta Crystallogr B Struct Sci Cryst Eng Mater

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In a search for new crystalline forms of linezolid with modified thermal properties five cocrystals of this wide range antibiotic with aromatic acids were obtained via mechanochemical grinding and analyzed with single crystal X-ray diffraction, solid-state NMR spectroscopy, powder X-ray diffraction and DSC measurements. The coformers used in this study were benzoic acid, p-hydroxybenzoic acid, protocatechuic acid, γ-resorcylic acid and gallic acid. In each of the cocrystals distinct structural features have been found, including a variable amount of water and different heterosynthons, indicating that there is more than one type of intermolecular interaction preferred by the linezolid molecule. Basing on the frequency of the observed supramolecular synthons, the proposed hierarchy of the hydrogen-bond acceptor sites of linezolid (LIN) is C=Oamide > C=Ooxazolidone > C—O—Cmorpholine > C—N—Cmorpholine > C—O—Coxazolidone. In addition, aromatic–aromatic interactions were found to be important in the stabilization of the analyzed structures. The obtained cocrystals show modified thermal properties, with four of them having melting points lower than the temperature of the phase transition from linezolid form II to linezolid form III. Such a change in this physicochemical property allows for the future application of melting-based techniques of introducing linezolid into drug delivery systems. In addition a change in water solubility of linezolid upon cocrystalization was evaluated, but only in the case of the cocrystal with protocatechuic acid was there a significant (43%) improvement in solubility in comparison with linezolid.

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What Is Special about Aromatic–Aromatic Interactions? Significant Attraction at Large Horizontal Displacement

Cited by 51 publications

References 57 publications

Syntheses, Structures, Reactivities, and Basicities of Quinolinyl and Isoquinolinyl Complexes of an Electron Rich Chiral Rhenium Fragment and Their Electrophilic Addition Products

Syntheses, Structures, Reactivities, and Basicities of Quinolinyl and Isoquinolinyl Complexes of an Electron Rich Chiral Rhenium Fragment and Their Electrophilic Addition Products

Are Heavy Pnictogen‐π Interactions Really “π Interactions”?

Structural variety of heterosynthons in linezolid cocrystals with modified thermal properties

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