Theoretical aspects of the enhancement of metal binding affinity by intramolecular hydrogen bonding and modulating pKavalues

2017 ◽  
Vol 41 (24) ◽  
pp. 15110-15119 ◽  
Author(s):  
Ahmad Motahari ◽  
Alireza Fattahi
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Binding Affinity ◽  
Metal Binding ◽  
Intramolecular Hydrogen Bonding ◽  
Hydrogen Bond Network ◽  
Bond Network ◽  
The Stability ◽  
Intramolecular Hydrogen

The stability balance shows that the hydrogen bond network and modulation of pKavalues can enhance the metal binding affinity.

Supramolecular assembling using synthons with NH—CO(S)—CS—NH and NH—CO—CO—NH functionalities: crystal structures of (S,S)-N,N′-monothiooxalyldileucine methyl ester and its dithio analogue

2004 ◽  
Vol 60 (1) ◽  
pp. 90-96 ◽  
Author(s):  
Biserka Kojić-Prodić ◽  
Berislav Perić ◽  
Zoran Štefanić ◽  
Anton Meden ◽  
Janja Makarević ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Methyl Ester ◽  
Crystal Structures ◽  
Hydrogen Bond Network ◽  
Asymmetric Unit ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Bond Network ◽  
Bonding Systems

To compare the structural properties of oxalamide and thiooxalamide groups in the formation of hydrogen bonds suitable for supramolecular assemblies a series of retropeptides was studied. Some of them, having oxalamide bridges, are gelators of organic solvents and water. However, retropeptides with oxygen replaced by the sp 2 sulfur have not exhibited such properties. The crystal structures of the two title compounds are homostructural, i.e. they have similar packing arrangements. The monothio compound crystallizes in the orthorhombic space group P212121 with two molecules in the asymmetric unit arranged in a hydrogen-bond network with an approximate 41 axis along the crystallographic b axis. However, the dithio and dioxo analogues crystallize in the tetragonal space group P41 with similar packing patterns and hydrogen-bonding systems arranged in agreement with a crystallographic 41 axis. Thus, these two analogues are isostructural having closely related hydrogen-bonding patterns in spite of the different size and polarity of oxygen and sulfur which serve as the proton acceptors.

scholarly journals Conformational analysis and intramolecular interactions in monosubstituted phenylboranes and phenylboronic acids

2013 ◽  
Vol 9 ◽  
pp. 1127-1134 ◽  
Author(s):  
Josué M Silla ◽  
Rodrigo A Cormanich ◽  
Roberto Rittner ◽  
Matheus P Freitas
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Conformational Analysis ◽  
Conformational Equilibrium ◽  
Intramolecular Hydrogen Bonding ◽  
Intramolecular Interactions ◽  
Coupling Constant ◽  
Intramolecular Hydrogen ◽  
Phenylboronic Acids ◽  
Electron Donation

A 1 TS J F,H(O) coupling pathway, dictated by a hydrogen bond, in some 2-fluorobenzoic acids has been observed, while such an interaction does not occur in 2-fluorophenol. Thus, this work reports the conformational analysis of 2-fluorophenylboronic acid (1), in order to evaluate a possible intramolecular OH∙∙∙F hydrogen bond in comparison to an nF→pB interaction, which mimics the quantum nF→σ*OH hydrogen bond that would be expected in 2-fluorophenol. 2-Fluorophenylborane (3), which does not experience hydrogen bonding, was used to verify whether nF→pB interaction governs the conformational equilibrium in 1 due to a predominant OH∙∙∙F hydrogen bond or to other effects. A series of 2-X-phenylboranes (X = Cl, Br, NH2, PH2, OH and SH) were further computationally analyzed to search for electron donors to boron, capable of influencing the conformational equilibrium. Overall, the intramolecular OH∙∙∙F hydrogen bond in 1 is quite stabilizing and dictates the 1 h J F,H(O) coupling constant. Moreover, electron donation to the empty p orbital of boron (for noncoplanar BH2 moiety relative to the phenyl ring) is also significantly stabilizing for the NH2 and PH2 derivatives, but not enough to make the corresponding conformers appreciably populated, because of steric effects and the loss of πCC→pB resonance. Thus, the results found earlier for 2-fluorophenol about the lack of intramolecular hydrogen bonding are now corroborated.

scholarly journals Docking of Platinum Compounds on Cube Rhombellane Functionalized Homeomorphs

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 749
Author(s):  
Beata Szefler ◽  
Przemysław Czeleń
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonds ◽  
Binding Affinity ◽  
Fullerene C60 ◽  
C60 Fullerene ◽  
Binding Affinities ◽  
Hydrogen Bond Network ◽  
Platinum Compounds ◽  
Anti Cancer ◽  
Bond Network

Platinum compounds are anti-cancer drugs and can bind to canonical purine bases, mainly guanine, found within double helical DNA. Platinum compounds can be transferred directly to pathologically altered sites in a specific and site-oriented manner by nanocarriers as potential nanocarriers for carboplatin. Two types of nanostructures were used as potential nanocarriers for carboplatin, the first were functionalized C60 fullerene molecules and the second were rhombellanes. The analyzed nanostructures show considerable symmetry, which affects the affinity of the studied nanocarriers and ligands. Thus symmetry of nanostructures affects the distribution of binding groups on their surface. After the docking procedure, analysis of structural properties revealed many interesting features. In all described cases, binding affinities of complexes of platinum compounds with functionalized fullerene C60 are higher compared with affinities of complexes of platinum compounds with rhombellane structures. All platinum compounds easily create complexes with functionalized fullerene C60, CID_16156307, and at the same time show the highest binding affinity. The binding affinities of lobaplatin and heptaplatin are higher compared with oxaliplatin and nedaplatin. The high value of binding affinity and equilibrium constant K is correlated with creation of strong and medium hydrogen bonds or is correlated with forming a hydrogen bond network. The performed investigations enabled finding nanocarriers for lobaplatin, heptaplatin, oxaliplatin and nedaplatin molecules.

Tautomerism and hydrogen bonding in guaninium phosphite and guaninium phosphate salts

2007 ◽  
Vol 63 (3) ◽  
pp. 448-458 ◽  
Author(s):  
El-Eulmi Bendeif ◽  
Slimane Dahaoui ◽  
Nourredine Benali-Cherif ◽  
Claude Lecomte
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Crystal Structures ◽  
Monoclinic Space Group ◽  
Data Sets ◽  
Hydrogen Bond Network ◽  
Space Group ◽  
X Ray ◽  
Bond Network ◽  
Phosphate Salts

The crystal structures of three similar guaninium salts, guaninium monohydrogenphosphite monohydrate, C5H6N5O+·H2O3P−·H2O, guaninium monohydrogenphosphite dihydrate, C5H6N5O+·H2O3P−·2H2O, and guaninium dihydrogenmonophosphate monohydrate, C5H6N5O+·H2O4P−·H2O, are described and compared. The crystal structures have been determined from accurate single-crystal X-ray data sets collected at 100 (2) K. The two phosphite salts are monoclinic, space group P21/c, with different packing and the monophosphate salt is also monoclinic, space group P21/n. An investigation of the hydrogen-bond network in these guaninium salts reveals the existence of two ketoamine tautomers, the N9H form and an N7H form.

scholarly journals Intra-molecular Interactions in Porous Covalent Organic Frameworks

2014 ◽  
Vol 70 (a1) ◽  
pp. C530-C530
Author(s):  
Rahul Banerjee
Keyword(s):  
Hydrogen Bonding ◽  
Schiff Base ◽  
Molecular Interactions ◽  
Chemical Stability ◽  
Intramolecular Hydrogen Bonding ◽  
Covalent Organic Frameworks ◽  
Covalent Organic Framework ◽  
New Strategy ◽  
The Stability ◽  
Intramolecular Hydrogen

A new strategy of intramolecular hydrogen bonding in 2D covalent organic framework as an extra stabilizing factor has been introduced, which helps to improve the crystallinity, porosity and chemical stability of the COF. Using this concept, highly stable porphyrin containing covalent organic frameworks have been synthesized using the Schiff base reaction. The stability of the COFs mainly arises due to the strong intramolecular O-H...N=C hydrogen bonding. Validation of this postulate was cross-checked by synthesizing methoxy (OCH3) substituted COF in which no hyrogen bonding exists. It was found that methoxy substituted COF have a low crystallinity, porosity and chemical stability as compared to hydrogen bonded COF.

scholarly journals Separation of planar rotamers through intramolecular hydrogen bonding in polysubstituted 5-nitrosopyrimidines

2014 ◽  
Vol 50 (94) ◽  
pp. 14892-14895 ◽  
Author(s):  
L. Čechová ◽  
E. Procházková ◽  
I. Císařová ◽  
M. Dračínský ◽  
Z. Janeba
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Intramolecular Hydrogen Bond ◽  
Chemical Species ◽  
Intramolecular Hydrogen Bonding ◽  
Nitroso Group ◽  
Group Orientation ◽  
Intramolecular Hydrogen

Unique isolation of pairs of planar rotamers, planamers, as chemical species differing only in nitroso group orientation, separable through the presence of a single intramolecular hydrogen bond, is reported.

scholarly journals (Acetonitrile-κN)aqua[N,N′-bis(pyridin-2-ylmethyl)ethane-1,2-diamine-κ4N,N′,N′′,N′′′]zinc(II) perchlorate

2017 ◽  
Vol 73 (10) ◽  
pp. 1568-1571
Author(s):  
Ugochukwu Okeke ◽  
Yilma Gultneh ◽  
Ray J. Butcher
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Three Dimensional ◽  
Structural Features ◽  
Hydrogen Bond Network ◽  
Asymmetric Unit ◽  
Bond Network ◽  
Bifurcated Hydrogen Bond ◽  
Coordinated Water ◽  
Ionic Hydrogen Bonding

The structure of the title compound, [Zn(C14H18N4)(C2H3N)(H2O)](ClO4)2, contains a six-coordinate cation consisting of the tetradentate bispicen ligand, coordinated water, and coordinated acetonitrile, with the latter two ligands adopting acisconfiguration. There are two formula units in the asymmetric unit. Both cations show almost identical structural features with the bispicen ligand adopting the more commoncis-β conformation. One of the four perchlorate anions is disordered over two positions, with occupancies of 0.9090 (15) and 0.0910 (15). There is extensive inter-ionic hydrogen bonding between the perchlorate anions and O—H and N—H groups in the cations, including a bifurcated hydrogen bond between an N—H group and two O atoms of one perchlorate anion. As a result of this extended hydrogen-bond network, the ions are linked into a complex three-dimensional array.

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