scholarly journals Magnesium–halobenzene bonding: mapping the halogen sigma-hole with a Lewis-acidic complex

2021 ◽  
Author(s):  
Alexander Friedrich ◽  
Jürgen Pahl ◽  
Jonathan Eyselein ◽  
Jens Langer ◽  
Nico van Eikema Hommes ◽  
...  
Keyword(s):  
Acidic Complex ◽  
Sigma Hole

Complexes of a highly Lewis acidic Mg cation and the full series of Ph–X (X = F, Cl, Br, I) have been structurally characterized. The Mg⋯X–Ph angle decreases with halogen size on account of the growing halogen σ-hole.

scholarly journals Modulating Chalcogen Bonding and Halogen Bonding Sigma‐Hole Donor Atom Potency and Selectivity for Halide Anion Recognition

2021 ◽  
Author(s):  
Andrew Docker ◽  
Charles Guthrie ◽  
Heike Kuhn ◽  
Paul D. Beer
Keyword(s):  
Anion Recognition ◽  
Halogen Bonding ◽  
Donor Atom ◽  
Halide Anion ◽  
Sigma Hole

Computational insight into the halogen bonded self-assembly of hexa-coordinated metalloporphyrins

2020 ◽  
Vol 22 (20) ◽  
pp. 11558-11566 ◽  
Author(s):  
Jyoti Rani ◽  
Vratta Grover ◽  
Swati Dhamija ◽  
Hatem M. Titi ◽  
Ranjan Patra
Keyword(s):  
Self Assembly ◽  
Ring Current ◽  
Axial Position ◽  
Direct Influence ◽  
Halogen Atoms ◽  
Sigma Hole ◽  
Insight Into

A direct influence of porphyrin's ring current on the sigma-hole potential of halogen atoms at the axial position of metalloporphyrins during halogen bonded self-assembly is determined in this study.

scholarly journals The Thiophene “Sigma-Hole” as a Concept for Preorganized, Specific Recognition of G⋅C Base Pairs in the DNA Minor Groove

2016 ◽  
Vol 22 (43) ◽  
pp. 15404-15412 ◽  
Author(s):  
Pu Guo ◽  
Ananya Paul ◽  
Arvind Kumar ◽  
Abdelbasset A. Farahat ◽  
Dhiraj Kumar ◽  
...  
Keyword(s):  
Minor Groove ◽  
Base Pairs ◽  
Dna Minor Groove ◽  
Specific Recognition ◽  
Sigma Hole

scholarly journals Adaptive responses of sterically confined intramolecular chalcogen bonds

2018 ◽  
Vol 9 (35) ◽  
pp. 7027-7042 ◽  
Author(s):  
Karuthapandi Selvakumar ◽  
Harkesh B. Singh
Keyword(s):  
Chalcogen Atom ◽  
Adaptive Responses ◽  
Donor Behavior ◽  
Sigma Hole

The existence of intramolecular chalcogen bonds (IChBs) in 2,6-disubstituted arylchalcogen derivatives is determined by the substituents and the sigma hole donor behavior of the chalcogen atom in the molecule.

scholarly journals Theoretical Description of R–X⋯NH3 Halogen Bond Complexes: Effect of the R Group on the Complex Stability and Sigma-Hole Electron Depletion

Molecules ◽  
2020 ◽  
Vol 25 (3) ◽  
pp. 530
Author(s):  
Juan Zurita ◽  
Vladimir Rodriguez ◽  
Cesar Zambrano ◽  
Jose Ramón Mora ◽  
Luis Rincón ◽  
...  
Keyword(s):  
Halogen Bond ◽  
Theoretical Description ◽  
Binding Energies ◽  
Complex Stability ◽  
Ethyl Vinyl ◽  
Cooperative Effects ◽  
Pair Density ◽  
Leibler Divergence ◽  
Sigma Hole ◽  
The Stability

In the present work, a number of R–X⋯NH3 (X = Cl, Br, and I) halogen bonded systems were theoretical studied by means of DFT calculations performed at the ωB97XD/6-31+G(d,p) level of theory in order to get insights on the effect of the electron-donating or electron-withdrawing character of the different R substituent groups (R = halogen, methyl, partially fluorinated methyl, perfluoro-methyl, ethyl, vinyl, and acetyl) on the stability of the halogen bond. The results indicate that the relative stability of the halogen bond follows the Cl < Br < I trend considering the same R substituent whereas the more electron-withdrawing character of the R substituent the more stable the halogen bond. Refinement of the latter results, performed at the MP2/6-31+G(d,p) level showed that the DFT and the MP2 binding energies correlate remarkably well, suggesting that the Grimme’s type dispersion-corrected functional produces reasonable structural and energetic features of halogen bond systems. DFT results were also observed to agree with more refined calculations performed at the CCSD(T) level. In a further stage, a more thorough analysis of the R–Br⋯NH3 complexes was performed by means of a novel electron localization/delocalization tool, defined in terms of an Information Theory, IT, based quantity obtained from the conditional pair density. For the latter, our in-house developed C++/CUDA program, called KLD (acronym of Kullback–Leibler divergence), was employed. KLD results mapped onto the one-electron density plotted at a 0.04 a.u. isovalue, showed that (i) as expected, the localized electron depletion of the Br sigma-hole is largely affected by the electron-withdrawing character of the R substituent group and (ii) the R–X bond is significantly polarized due to the presence of the NH3 molecule in the complexes. The afore-mentioned constitutes a clear indication of the dominant character of electrostatics on the stabilization of halogen bonds in agreement with a number of studies reported in the main literature. Finally, the cooperative effects on the [Br—CN]n system (n = 1–8) was evaluated at the MP2/6-31+G(d,p) level, where it was observed that an increase of about ~14.2% on the complex stability is obtained when going from n = 2 to n = 8. The latter results were corroborated by the analysis of the changes on the Fermi-hole localization pattern on the halogen bond zones, which suggests an also important contribution of the electron correlation in the stabilization of these systems.

scholarly journals Lewis acid enhancement by hydrogen-bond donors for asymmetric catalysis

Science ◽  
2017 ◽  
Vol 358 (6364) ◽  
pp. 761-764 ◽  
Author(s):  
Steven M. Banik ◽  
Anna Levina ◽  
Alan M. Hyde ◽  
Eric N. Jacobsen
Keyword(s):  
Hydrogen Bond ◽  
Catalytic Activity ◽  
Asymmetric Catalysis ◽  
Small Molecule ◽  
Lewis Acid ◽  
Low Temperatures ◽  
Noncovalent Interactions ◽  
Enantioselective Reactions ◽  
Acidic Complex ◽  
Hydrogen Bond Donors

Small-molecule dual hydrogen-bond (H-bond) donors such as ureas, thioureas, squaramides, and guanidinium ions enjoy widespread use as effective catalysts for promoting a variety of enantioselective reactions. However, these catalysts are only weakly acidic and therefore require highly reactive electrophilic substrates to be effective. We introduce here a mode of catalytic activity with chiral H-bond donors that enables enantioselective reactions of relatively unreactive electrophiles. Squaramides are shown to interact with silyl triflates by binding the triflate counterion to form a stable, yet highly Lewis acidic, complex. The silyl triflate-chiral squaramide combination promotes the generation of oxocarbenium intermediates from acetal substrates at low temperatures. Enantioselectivity in nucleophile additions to the cationic intermediates is then controlled through a network of noncovalent interactions between the squaramide catalyst and the oxocarbenium triflate.

Could an anisotropic molecular mechanics/dynamics potential account for sigma hole effects in the complexes of halogenated compounds?

2013 ◽  
Vol 34 (13) ◽  
pp. 1125-1135 ◽  
Author(s):  
Krystel El Hage ◽  
Jean-Philip Piquemal ◽  
Zeina Hobaika ◽  
Richard G. Maroun ◽  
Nohad Gresh
Keyword(s):  
Molecular Mechanics ◽  
Halogenated Compounds ◽  
Sigma Hole

Computational approaches and sigma-hole interactions: general discussion

2017 ◽  
Vol 203 ◽  
pp. 131-163 ◽  
Author(s):  
Christer B. Aakeröy ◽  
Saman Alavi ◽  
Lee Brammer ◽  
David L. Bryce ◽  
Timothy Clark ◽  
...  
Keyword(s):  
Computational Approaches ◽  
Sigma Hole

Synthesis of porous and acidic complex metal oxide catalyst based on group 5 and 6 elements

2012 ◽  
Vol 185 (1) ◽  
pp. 224-229 ◽  
Author(s):  
Toru Murayama ◽  
Nozomi Kuramata ◽  
Shunsuke Takatama ◽  
Kosuke Nakatani ◽  
Shoko Izumi ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Oxide Catalyst ◽  
Metal Oxide Catalyst ◽  
Complex Metal ◽  
Acidic Complex ◽  
Group 5 ◽  
Complex Metal Oxide

Biological control of S-nitrosothiol reactivity: potential role of sigma-hole interactions

2020 ◽  
Vol 22 (12) ◽  
pp. 6595-6605
Author(s):  
Niloufar Hendinejad ◽  
Qadir K. Timerghazin
Keyword(s):  
Nitric Oxide ◽  
Biological Control ◽  
Hydrogen Bonding ◽  
Lewis Acids ◽  
Potential Role ◽  
Lewis Bases ◽  
Sigma Hole ◽  
Derivatives Of

S-Nitrosothiols, ubiquitous biological derivatives of nitric oxide, can engage in σ-hole/bonding with Lewis bases, which, in combination with hydrogen bonding with Lewis acids, could be the basis of enzymatic control of S-nitrosothiol reactions.

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