scholarly journals Molecular Recognition by Pillar[5]arenes: Evidence for Simultaneous Electrostatic and Hydrophobic Interactions

Pharmaceutics ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 60
Author(s):  
Borja Gómez-González ◽  
Luis García-Río ◽  
Nuno Basílio ◽  
Juan C. Mejuto ◽  
Jesus Simal-Gandara
Keyword(s):  
Molecular Recognition ◽  
Inclusion Complexes ◽  
Electrostatic Interactions ◽  
Alkyl Chain ◽  
Hydrophobic Interactions ◽  
Binding Constants ◽  
Ionic Interactions ◽  
Hydrophobic Effects ◽  
Hydrophobic Character ◽  
Electrostatic And Hydrophobic Interactions

The formation of inclusion complexes between alkylsulfonate guests and a cationic pillar[5]arene receptor in water was investigated by NMR and ITC techniques. The results show the formation of host-guest complexes stabilized by electrostatic interactions and hydrophobic effects with binding constants of up to 107 M−1 for the guest with higher hydrophobic character. Structurally, the alkyl chain of the guest is included in the hydrophobic aromatic cavity of the macrocycle while the sulfonate groups are held in the multicationic portal by ionic interactions.

scholarly journals Molecular Recognition by Pillar[5]arenes: Balance Between Hydrophobic and Electrostatic Interactions

2021 ◽  
Author(s):  
B. Gómez-González ◽  
L. García-Río ◽  
N. Basilio ◽  
J.C. Mejuto ◽  
J. Simal-Gandara
Keyword(s):  
Molecular Recognition ◽  
Inclusion Complexes ◽  
Electrostatic Interactions ◽  
Alkyl Chain ◽  
Binding Constants ◽  
Ionic Interactions ◽  
Hydrophobic Character

The formation of inclusion complexes between alkylsulfonate guests and a cationic pillar[5]arene receptor in water was investigated by NMR and ITC techniques. The results show the formation of host-guest complexes stabilized by electrostatic interactions and hydrophobics effects with binding constants of up to 107 M-1 for the guest with higher hydrophobic character. Structurally, the alkyl chain of the guest is included in the hydrophobic aromatic cavity of the macrocycle while the sulfonate groups are hold in the multicationic portal by ionic interactions.

The binding of bilirubin by immobilized oligopeptides containing lysine

1989 ◽  
Vol 67 (4) ◽  
pp. 596-602 ◽  
Author(s):  
M. Bouvier ◽  
G. R. Brown ◽  
L. E. St-Pierre
Keyword(s):  
Binding Sites ◽  
Hydrophobic Interactions ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Binding Constants ◽  
Ionic Interactions ◽  
Structural Factors ◽  
Adsorption Behaviour ◽  
Bilirubin Adsorption ◽  
Site Binding

Peptides consisting of portions of the sequence Arg-(Lys)2-(Ser)2-Lys-(Ala)3 have been immobilized onto a polyacrylamide support by solid phase peptide synthesis. Isotherms at 0 °C for the adsorption of bilirubin from phosphate buffer by these peptide resins are highly dependent on pH, in the range 7.80–11.00, demonstrating the importance of ionic interactions. The adsorption behaviour of bilirubin-related tetrapyrroles shows that structural factors also influence the process. Peptide resins containing two or more residues of lysine have two binding sites on each pendant and are characterized by positive cooperativity, to a degree that is highly dependent on the number of residues. It is proposed that bilirubin molecules bound by lysine-containing pendants are stacked, the dimer state being stabilized by π-π electron interactions, hydrogen bonds, and hydrophobic interactions. Site binding constants show that arginine-containing pendants manifest a stronger affinity for bilirubin. Keywords: bilirubin, adsorption, lysine, oligopeptides, cooperativity.

Functionalized nanographene sheets with high antiviral activity through synergistic electrostatic and hydrophobic interactions

Nanoscale ◽  
2019 ◽  
Vol 11 (34) ◽  
pp. 15804-15809 ◽  
Author(s):  
Ievgen S. Donskyi ◽  
Walid Azab ◽  
Jose Luis Cuellar-Camacho ◽  
Guy Guday ◽  
Andreas Lippitz ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Electrostatic Interactions ◽  
Hydrophobic Interactions ◽  
Synergistic Action ◽  
Schematic Representation ◽  
Electrostatic And Hydrophobic Interactions ◽  
High Antiviral Activity ◽  
Aliphatic Chains

Schematic representation of synergistic action of electrostatic interactions of polyglycerol sulfate and conjugated aliphatic chains to the surface of nG-PGS.

scholarly journals Interactions between adsorbents and adsorbates in aqueous solutions

2020 ◽  
Vol 92 (10) ◽  
pp. 1655-1662
Author(s):  
Zhijian Wu ◽  
Xiushen Ye ◽  
Haining Liu ◽  
Huifang Zhang ◽  
Zhong Liu ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Electrostatic Interactions ◽  
Hydrophobic Interactions ◽  
Solution Ph ◽  
Electrostatic And Hydrophobic Interactions

AbstractAdsorption is one of the most widely used processes in physicochemical operations. To design an adsorbent for a specific adsorbate, it is important to understand the interactions between adsorbents and adsorbates, which are very important for both adsorption capacity and selectivity. Electrostatic interactions, hydrogen bonding, hydrophobic interactions, complexation, and precipitation are comprehensively discussed. Adjusting solution pH and ionic strength is an effective method to improve the adsorption, especially when electrostatic and hydrophobic interactions are main interactions. With the increase in ionic strength, the hydrophobic interactions between adsorbents and adsorbates increase, while the electrostatic interactions decrease.

Template mediated crystal engineering

1994 ◽  
Vol 52 ◽  
pp. 480-481
Author(s):  
Brigid R. Heywood ◽  
S. Champ
Keyword(s):  
Crystal Engineering ◽  
Electrostatic Interactions ◽  
Alkyl Chain ◽  
Crystallographic Axis ◽  
Two Dimensional ◽  
Engineering Process ◽  
Solution Interface ◽  
Extensive Program ◽  
Geometric Homology ◽  
Long Alkyl Chain

Recent work on the crystallisation of inorganic crystals under compressed monomolecular surfactant films has shown that two dimensional templates can be used to promote the oriented nucleation of solids. When a suitable long alkyl chain surfactant is cast on the crystallisation media a monodispersied population of crystals forms exclusively at the monolayer/solution interface. Each crystal is aligned with a specific crystallographic axis perpendicular to the plane of the monolayer suggesting that nucleation is facilitated by recognition events between the nascent inorganic solid and the organic template.For example, monolayers of the long alkyl chain surfactant, stearic acid will promote the oriented nucleation of the calcium carbonate polymorph, calcite, on the (100) face, whereas compressed monolayers of n-eicosyl sulphate will induce calcite nucleation on the (001) face, (Figure 1 & 2). An extensive program of research has confirmed the general principle that molecular recognition events at the interface (including electrostatic interactions, geometric homology, stereochemical complementarity) can be used to promote the crystal engineering process.

Interaction of sulphone based reactive dyes with cationic surfactant: a spectroscopic and conductometric study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Misbah Iram ◽  
Hamadia Sultana ◽  
Muhammad Usman ◽  
Bazgha Ahmad ◽  
Nadia Akram ◽  
...  
Keyword(s):  
Strong Interaction ◽  
Cetyltrimethylammonium Bromide ◽  
Hydrophobic Interactions ◽  
Reactive Dyes ◽  
Micellar System ◽  
Palisade Layer ◽  
Micellar Systems ◽  
Gibbs Energies ◽  
Electrostatic And Hydrophobic Interactions ◽  
Conductometric Study

Abstract Interaction of sulphone based reactive dyes, designated as dye-1 and dye-2, with cationic micellar system of cetyltrimethylammonium bromide (CTAB), has been investigated by spectroscopic and conductometeric measurements. Efficiency of the selected micellar systems is assessed by the values of binding constant (K b ), partition coefficient (K x ) and respective Gibbs energies. Critical micelle concentration (CMC) of surfactant, electrostatic and hydrophobic interactions as well as polarity of the medium plays significant role in this phenomenon. The negative values of Gibbs energies of binding (∆G b ) and partition (∆G p ) predicts the feasibility and spontaneity of respective processes. Similarly negative values of ∆G m and ∆H m and positive values of ∆S m , calculated from conductometeric data, further, revealed the exothermicity, spontaneity and, thus, stability of system. The results, herein, have disclosed the strong interaction between dye and surfactant molecules. The dye-2 has been observed to be solubilized to greater extent, as compared to dye 1, due to strong interaction ith hydrophiles of CTAB and accommodation of its molecules in palisade layer of micelle closer to the micelle/water interface.

scholarly journals Molecular recognition of organic ammonium ions in solution using synthetic receptors

2010 ◽  
Vol 6 ◽  
Author(s):  
Andreas Späth ◽  
Burkhard König
Keyword(s):  
Molecular Recognition ◽  
Hydrophobic Interactions ◽  
Covalent Bond ◽  
Ammonium Ion ◽  
Synthetic Receptors ◽  
Ammonium Ions ◽  
Wide Range ◽  
Covalent Bond Formation ◽  
Reversible Covalent ◽  
Ion Receptors

Ammonium ions are ubiquitous in chemistry and molecular biology. Considerable efforts have been undertaken to develop synthetic receptors for their selective molecular recognition. The type of host compounds for organic ammonium ion binding span a wide range from crown ethers to calixarenes to metal complexes. Typical intermolecular interactions are hydrogen bonds, electrostatic and cation–π interactions, hydrophobic interactions or reversible covalent bond formation. In this review we discuss the different classes of synthetic receptors for organic ammonium ion recognition and illustrate the scope and limitations of each class with selected examples from the recent literature. The molecular recognition of ammonium ions in amino acids is included and the enantioselective binding of chiral ammonium ions by synthetic receptors is also covered. In our conclusion we compare the strengths and weaknesses of the different types of ammonium ion receptors which may help to select the best approach for specific applications.

scholarly journals Characterization of Virus Adsorption by Using DEAE-Sepharose and Octyl-Sepharose

2002 ◽  
Vol 68 (8) ◽  
pp. 3965-3968 ◽  
Author(s):  
Patricia A. Shields ◽  
Samuel R. Farrah
Keyword(s):  
Sodium Chloride ◽  
Electrostatic Interactions ◽  
Hydrophobic Interactions ◽  
Chloride Concentration ◽  
Sodium Chloride Concentration ◽  
Virus Adsorption ◽  
Nacl Concentration

ABSTRACT Viruses were characterized by their adsorption to DEAE-Sepharose or by their elution from octyl-Sepharose by using buffered solutions of sodium chloride with different ionic strengths. Viruses whose adsorption to DEAE-Sepharose was reduced most rapidly by an increase in the sodium chloride concentration were considered to have the weakest electrostatic interactions with the solids; these viruses included MS2, E1, and φX174. Viruses whose adsorption to DEAE-Sepharose was reduced least rapidly were considered to have the strongest electrostatic interactions with the column; these viruses included P1, T4, T2, and E5. All of the viruses studied adsorbed to octyl-Sepharose in the presence of 4 M NaCl. Viruses that were eluted most rapidly following a decrease in the concentration of NaCl were considered to have the weakest hydrophobic interactions with the column; these viruses included φX174, CB4, and E1. Viruses that were eluted least rapidly from the columns after the NaCl concentration was decreased were considered to have the strongest hydrophobic interactions with the column; these viruses included f2, MS2, and E5.

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