Sigma/pi interactions in [2.2]paracyclophanes. PE investigations on octamethyltetrasila[2.2]paracyclophane and octamethyltetrasila[2.2](2,5)thiophenophane and -furanophane

1988 ◽  
Vol 110 (13) ◽  
pp. 4117-4120 ◽  
Author(s):  
Rolf. Gleiter ◽  
Wolfgang. Schaefer ◽  
Gerhard. Krennrich ◽  
Hideki. Sakurai
Keyword(s):  
Pi Interactions

Stereospecific 1,3-H Transfer of Indenols Proceeds via Persistent Ion-Pairs Anchored By NH···Pi Interactions

2018 ◽  
Author(s):  
David Ascough ◽  
Fernanda Duarte ◽  
Robert Paton
Keyword(s):  
Computational Analysis ◽  
Ion Pairs ◽  
Ion Pair ◽  
Hydrogen Atom Transfer ◽  
Polar Solvents ◽  
Chirality Transfer ◽  
Activation Barriers ◽  
Sense And Avoid ◽  
Phase Dynamics ◽  
Pi Interactions

The base-catalyzed rearrangement of arylindenols is a rare example of a suprafacial [1,3]-hydrogen atom transfer. The mechanism has been proposed to proceed via sequential [1,5]-sigmatropic shifts, which occur in a selective sense and avoid an achiral intermediate. A computational analysis using quantum chemistry casts serious doubt on these suggestions: these pathways have enormous activation barriers and in constrast to what is observed experimentally, they overwhelmingly favor a racemic product. Instead we propose that a suprafacial [1,3]-prototopic shift occurs in a two-step deprotonation/reprotonation sequence. This mechanism is favored by 15 kcal mol<sup>-1</sup> over that previously proposed. Most importantly, this is also consistent with stereospecificity since reprotonation occurs rapidly on the same p-face. We have used explicitly-solvated molecular dynamics studies to study the persistence and condensed-phase dynamics of the intermediate ion-pair formed in this reaction. Chirality transfer is the result of a particularly resilient contact ion-pair, held together by electrostatic attraction and a critical NH···p interaction which ensures that this species has an appreciable lifetime even in polar solvents such as DMSO and MeOH.

Unusually Strong Interactions Mediated by Both .pi.-.pi. Stacking and CH-.pi. Interactions Present in the Dimer of Nickel(II) Complex Coordinated with n-Butyl-Substituted Salen

1995 ◽  
Vol 117 (8) ◽  
pp. 2377-2378 ◽  
Author(s):  
Kazuo Miyamura ◽  
Akiko Mihara ◽  
Takashi Fujii ◽  
Yohici Gohshi ◽  
Youichi Ishii
Keyword(s):  
Strong Interactions ◽  
Pi Stacking ◽  
Pi Interactions

The nature of .pi.-.pi. interactions

1990 ◽  
Vol 112 (14) ◽  
pp. 5525-5534 ◽  
Author(s):  
Christopher A. Hunter ◽  
Jeremy K. M. Sanders
Keyword(s):  
Pi Interactions

scholarly journals Unexpectedly Large Couplings Between Orthogonal Units in Anthraquinone Polymers

2019 ◽  
Author(s):  
Rocco Peter Fornari ◽  
Piotr de Silva
Keyword(s):  
Molecular Dynamics ◽  
Density Functional Theory ◽  
Ab Initio ◽  
Density Functional ◽  
Lone Pair ◽  
Localized States ◽  
Ab Initio Molecular Dynamics ◽  
Coupling Mechanism ◽  
Functional Theory ◽  
Pi Interactions

Directly linked polyanthraquinones have relatively large electronic couplings between charge-localized states despite near-orthogonality of the monomer units. By using density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulations, we investigate this unusual coupling mechanism and show that this is due to strong lone pair-pi interactions, which are maximized around orthogonal conformations. We find that such materials are largely resilient to dynamic disorder and are promising for organic electronics applications.

scholarly journals Do Cation-PI Interactions Occur in Lipid Bilayers Between Phosphatidylcholine Headgroups and Interfacially Localized Tryptophans?

2010 ◽  
Vol 98 (3) ◽  
pp. 486a ◽  
Author(s):  
Jacques P.F. Doux ◽  
J. Antoinette Killian
Keyword(s):  
Lipid Bilayers ◽  
Pi Interactions

Heteroleptic copper(i) halides with triphenylphosphine and acetylthiourea: synthesis, characterization and biological studies (experimental and molecular docking)

2019 ◽  
Vol 43 (48) ◽  
pp. 19318-19330 ◽  
Author(s):  
Syed Ishtiaq Khan ◽  
Sajjad Ahmad ◽  
Ataf Ali Altaf ◽  
Muhammad Khawar Rauf ◽  
Amin Badshah ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Biological Activities ◽  
Biological Studies ◽  
Pi Interactions

This manuscript presents the synthesis of acetylthiourea and triphenylphosphene based hetroleptic copper(i) halides and their biological activities. H-bonding and hydrophobic pi-interactions were found important for their biological activities.

Counterintuitive consequences of filled ligand .pi. interactions with metal d orbitals

1980 ◽  
Vol 19 (12) ◽  
pp. 3865-3866 ◽  
Author(s):  
John L. Hubbard ◽  
Dennis L. Lichtenberger
Keyword(s):  
Pi Interactions ◽  
D Orbitals
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