Preferential binding of unsaturated hydrocarbons in aryl-bisimidazolium·cucurbit[8]uril complexes furbishes evidence for small-molecule π–π interactions

Restricting the internal cavity size of cucurbit[8]uril with auxiliary guests sets up an intermolecular interaction chamber for hydrocarbons, which provides insights into dispersion, arene–hydrocarbon interactions, and desolvation effects.

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Effect of crystal freezing and small-molecule binding on internal cavity size in a large protein: X-ray and docking studies of lipoxygenase at ambient and low temperature at 2.0 Å resolution

Acta Crystallographica Section D Biological Crystallography ◽

10.1107/s0907444906016982 ◽

2006 ◽

Vol 62 (7) ◽

pp. 766-775 ◽

Cited By ~ 19

Author(s):

E. Skrzypczak-Jankun ◽

O. Y. Borbulevych ◽

M. I. Zavodszky ◽

M. R. Baranski ◽

K. Padmanabhan ◽

...

Keyword(s):

Low Temperature ◽

Small Molecule ◽

Docking Studies ◽

Internal Cavity ◽

Cavity Size ◽

Large Protein ◽

X Ray ◽

Protein X

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Contribution of C−H⋯π Interactions to Polymorphic Transitions of a Molecular Crystal with Disordered Fragments

10.26434/chemrxiv.14345843 ◽

2021 ◽

Author(s):

Takuya Taniguchi ◽

Daisuke Takagi ◽

Toru Asahi

Keyword(s):

High Temperature ◽

Single Crystal ◽

Intermolecular Interaction ◽

Molecular Crystal ◽

Interaction Analysis ◽

Polymorphic Transition ◽

Underlying Mechanism ◽

Polymorphic Transitions ◽

Π Interactions ◽

Β Phase

Polymorphic transition is important for the functionality of crystalline materials. However, the underlying mechanism remains unclear, especially when the crystal structure contains disordered fragments. We report that C−H⋯π interactions play an important role in polymorphic transitions in a molecular crystal with disordered fragments. The crystal has three phases, namely the a (< -80°C), β (-80-40°C), and γ (< 40°C) phases, which are reversible through single-crystal-to-single-crystal transformation in association with temperature change. Disorder of bulky tert-butyl substituents appears at high-temperature in the β and γ phases. Intermolecular interaction analysis based on Hirshfeld surfaces and related fingerprint plots revealed that the proportion of π⋯π interactions decreased, while that of C−H⋯π interactions increased, at the transition from a to β phase. The proportion of C−H⋯π interactions also increased at the transition from β to γ phase, but continuously decreased in the β phase due to elevated temperature. Intermolecular interaction energies clarified the contribution of C−H⋯π interactions to the stability of high-temperature crystal β and γ phases via polymorphic transitions. Our results potentially lead to design molecular crystals with polymorphic transitions.

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Crystal structures of four indole derivatives as possible cannabinoid allosteric antagonists

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s2056989015008476 ◽

2015 ◽

Vol 71 (6) ◽

pp. 654-659 ◽

Cited By ~ 4

Author(s):

Jamie R. Kerr ◽

Laurent Trembleau ◽

John M. D. Storey ◽

James L. Wardell ◽

William T. A. Harrison

Keyword(s):

Hydrogen Bond ◽

Crystal Structures ◽

Intermolecular Interaction ◽

Ring System ◽

Consistent Pattern ◽

Indole Derivatives ◽

Π Interactions

The crystal structures of four indole derivatives with various substituents at the 2-, 3- and 5-positions of the ring system are described, namely, ethyl 3-(5-chloro-2-phenyl-1H-indol-3-yl)-3-phenylpropanoate, C25H22ClNO2, (I), 2-bromo-3-(2-nitro-1-phenylethyl)-1H-indole, C16H13BrN2O2, (II), 5-methoxy-3-(2-nitro-1-phenylethyl)-2-phenyl-1H-indole, C23H20N2O3, (III), and 5-chloro-3-(2-nitro-1-phenylethyl)-2-phenyl-1H-indole, C22H17ClN2O2, (IV). The dominant intermolecular interaction in each case is an N—H...O hydrogen bond, which generates either chains or inversion dimers. Weak C—H...O, C—H...π and π–π interactions occur in these structures but there is no consistent pattern amongst them. Two of these compounds act as modest enhancers of CB1 cannabanoid signalling and two are inactive.

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The influence of directed π–π interactions in solution on the thin film organic semiconductor device properties of small molecule polymer blends

Soft Matter ◽

10.1039/c1sm05842h ◽

2011 ◽

Vol 7 (15) ◽

pp. 7065 ◽

Cited By ~ 11

Author(s):

Marie-Beatrice Madec ◽

Sean Butterworth ◽

Pablo Taboada ◽

Richard Heenan ◽

Mark Geoghegan ◽

...

Keyword(s):

Thin Film ◽

Polymer Blends ◽

Small Molecule ◽

Organic Semiconductor ◽

Semiconductor Device ◽

Π Interactions ◽

Device Properties

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Different N—H...π interactions in two indole derivatives

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s2056989016006162 ◽

2016 ◽

Vol 72 (5) ◽

pp. 699-703 ◽

Cited By ~ 3

Author(s):

Jamie R. Kerr ◽

Laurent Trembleau ◽

John M. D. Storey ◽

James L. Wardell ◽

William T. A. Harrison

Keyword(s):

Hydrogen Bonds ◽

Crystal Structures ◽

Intermolecular Interaction ◽

Aromatic Ring ◽

Stacking Interactions ◽

Indole Derivatives ◽

Asymmetric Unit ◽

Π Interactions ◽

Π Stacking

We describe the syntheses and crystal structures of two indole derivatives, namely 6-isopropyl-3-(2-nitro-1-phenylethyl)-1H-indole, C19H20N2O2, (I), and 2-(4-methoxyphenyl)-3-(2-nitro-1-phenylethyl)-1H-indole, C23H20N2O3, (II); the latter crystallizes with two molecules (AandB) with similar conformations (r.m.s. overlay fit = 0.139 Å) in the asymmetric unit. Despite the presence of O atoms as potential acceptors for classical hydrogen bonds, the dominant intermolecular interaction in each crystal is an N—H...π bond, which generates chains in (I) andA+AandB+Binversion dimers in (II). A different aromatic ring acts as the acceptor in each case. The packing is consolidated by C—H...π interactions in each case but aromatic π–π stacking interactions are absent.

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