Quantifying the hydrogen-bonding interaction between cation and anion of pure [EMIM][Ac] and evidencing the ion pairs existence in its extremely diluted water solution: Via 13 C, 1 H, 15 N and 2D NMR

2015 ◽  
Vol 1079 ◽  
pp. 120-129 ◽  
Author(s):  
Yu Chen ◽  
Shehong Li ◽  
Zhimin Xue ◽  
Mingyang Hao ◽  
Tiancheng Mu
Keyword(s):  
Hydrogen Bonding ◽  
Water Solution ◽  
Ion Pairs ◽  
2D Nmr ◽  
Hydrogen Bonding Interaction ◽  
Bonding Interaction

scholarly journals Crystal structures and hydrogen bonding in the morpholinium salts of four phenoxyacetic acid analogues

2015 ◽  
Vol 71 (11) ◽  
pp. 1392-1396 ◽  
Author(s):  
Graham Smith ◽  
Daniel E. Lynch
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Ion Pairs ◽  
Phenoxyacetic Acid ◽  
Dimensional Chain ◽  
Hydrogen Bonding Interaction ◽  
One Dimensional ◽  
Bonding Interaction ◽  
Graph Set ◽  
Dichlorophenoxy Acetic Acid

The anhydrous salts morpholinium (tetrahydro-2-H-1,4-oxazin-4-ium) phenoxyacetate, C4H10NO+·C8H7O3−, (I), morpholinium (4-fluorophenoxy)acetate, C4H10NO+·C8H6 FO3−, (II), and isomeric morpholinium (3,5-dichlorophenoxy)acetate (3,5-D), (III), and morpholinium (2,4-dichlorophenoxy)acetic acid (2,4-D), C4H10NO+·C8H5Cl2O3−, (IV), have been determined and their hydrogen-bonded structures are described. In the crystals of (I), (III) and (IV), one of the the aminium H atoms is involved in a three-centre asymmetric cation–anion N—H...O,O′R12(4) hydrogen-bonding interaction with the two carboxyl O-atom acceptors of the anion. With the structure of (II), the primary N—H...O interaction is linear. In the structures of (I), (II) and (III), the second N—H...Ocarboxylhydrogen bond generates one-dimensional chain structures extending in all cases along [100]. With (IV), the ion pairs are linked though inversion-related N—H...O hydrogen bonds [graph setR42(8)], giving a cyclic heterotetrameric structure.

Radical Enzymes Control the Chemistry of Their Highly Reactive Intermediates Using the Quantum Coulombic Effect

2020 ◽  
Author(s):  
Hossein Khalilian ◽  
Gino A. DiLabio
Keyword(s):  
Hydrogen Bonding ◽  
Molecular Orbital ◽  
Reactive Intermediates ◽  
Hydrogen Bonding Interaction ◽  
Orbital Ordering ◽  
Dynamic Nature ◽  
Radical Intermediate ◽  
Highest Occupied Molecular Orbital ◽  
Bonding Interaction ◽  
Close Proximity

Here, we report an exquisite strategy that the B12 enzymes exploit to manipulate the reactivity of their radical intermediate (Adenosyl radical). Based on the quantum-mechanic calculations, these enzymes utilize a little known long-ranged through space quantum Coulombic effect (QCE). The QCE causes the radical to acquire an electronic structure that contradicts the Aufbau Principle: The singly-occupied molecular orbital (SOMO) is no longer the highest-occupied molecular orbital (HOMO) and the radical is unable to react with neighbouring substrates. The dynamic nature of the enzyme and its structure is expected to be such that the reactivity of the radical is not restored until it is moved into close proximity of the target substrate. We found that the hydrogen bonding interaction between the nearby conserved glutamate residue and the ribose ring of Adenosyl radical plays a crucial role in manipulating the orbital ordering

Radical Enzymes Control the Chemistry of Their Highly Reactive Intermediates Using the Quantum Coulombic Effect

2020 ◽  
Author(s):  
Hossein Khalilian ◽  
Gino A. DiLabio
Keyword(s):  
Hydrogen Bonding ◽  
Molecular Orbital ◽  
Reactive Intermediates ◽  
Hydrogen Bonding Interaction ◽  
Orbital Ordering ◽  
Dynamic Nature ◽  
Radical Intermediate ◽  
Highest Occupied Molecular Orbital ◽  
Bonding Interaction ◽  
Close Proximity

Here, we report an exquisite strategy that the B12 enzymes exploit to manipulate the reactivity of their radical intermediate (Adenosyl radical). Based on the quantum-mechanic calculations, these enzymes utilize a little known long-ranged through space quantum Coulombic effect (QCE). The QCE causes the radical to acquire an electronic structure that contradicts the Aufbau Principle: The singly-occupied molecular orbital (SOMO) is no longer the highest-occupied molecular orbital (HOMO) and the radical is unable to react with neighbouring substrates. The dynamic nature of the enzyme and its structure is expected to be such that the reactivity of the radical is not restored until it is moved into close proximity of the target substrate. We found that the hydrogen bonding interaction between the nearby conserved glutamate residue and the ribose ring of Adenosyl radical plays a crucial role in manipulating the orbital ordering

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