scholarly journals Properly handling negative values in the calculation of binding constants by physicochemical modeling of spectroscopic titration data

2019 ◽  
Vol 33 (11) ◽  
Author(s):  
Nathanael P. Kazmierczak ◽  
Douglas A. Vander Griend
Keyword(s):  
Binding Constants ◽  
Physicochemical Modeling ◽  
Titration Data ◽  
Spectroscopic Titration

scholarly journals Water Soluble Host–Guest Chemistry Involving Aromatic N-Oxides and Sulfonateresorcinarene

Symmetry ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1751
Author(s):  
Kwaku Twum ◽  
Nicholas Schileru ◽  
Bianca Elias ◽  
Jordan Feder ◽  
Leena Yaqoo ◽  
...  
Keyword(s):  
Interaction Parameter ◽  
Binding Constants ◽  
Water Soluble ◽  
Electrostatic Attraction ◽  
Internal Cavity ◽  
Negative Cooperativity ◽  
Binding Isotherm ◽  
Shape Complementarity ◽  
Positive Cooperativity ◽  
Titration Data

Resorcinarenes decorated with sulfonate groups are anionic in nature and water soluble with a hydrophobic electron-rich interior cavity. These receptors are shown to bind zwitterionic aromatic mono-N-oxides and cationic di-N-oxide salts with varying spacer lengths. Titration data fit a 1:1 binding isotherm for the mono-N-oxides and 2:1 binding isotherm for the di-N-oxides. The first binding constants for the di-N-oxides (K1: 104 M−1) are higher compared to the neutral mono-N-oxide (K: 103 M−1) due to enhanced electrostatic attraction from a receptor with an electron-rich internal cavity and cationic and electron deficient N-oxides. The interaction parameter α reveals positive cooperativity for the di-N-oxide with a four-carbon spacer and negative cooperativity for the di-N-oxides that have spacers with more four carbons. This is attributed to shape complementarity between the host and the guest.

scholarly journals Characterization of Co(II)-PAMAM dendrimer complexes with polypropylene oxide core by using UV-VIS spectroscopy

2016 ◽  
Vol 35 (2) ◽  
pp. 263 ◽  
Author(s):  
Ali Serol Ertürk ◽  
Mustafa Ulvi Gürbüz ◽  
Metin Tülü ◽  
Abdürrezzak Emin Bozdoğan
Keyword(s):  
Pamam Dendrimer ◽  
Mri Contrast Agents ◽  
Mri Contrast ◽  
Polypropylene Oxide ◽  
Vis Spectroscopy ◽  
Complexation Agent ◽  
Titration Data ◽  
Spectroscopic Titration ◽  
Optimized Conditions

<p>The aim of this study was to characterize poly(amidoamine) (PAMAM) dendrimer complexes of Co(II) ions by using UV-Vis spectroscopy. For this aim, a generation-4 polypropylene oxide (Jeffamine<sup>®</sup> T-403) cored and amine-terminated PAMAM dendrimer (P<sub>4</sub>) was used as a model complexation agent. Optimum complexation condition for P<sub>4</sub> was determined by potentiometric and spectroscopic titration studies. Extent of protonation (EOP) of the amino groups of P<sub>4</sub> was determined from the potentiometric titration data and validated with spectroscopic titration data. The results indicated that pH 8 was the optimum dendrimer aqueous solution media, where the available number of tertiary amines present in P<sub>4 </sub>was the highest for possible metal complexation. At the optimized conditions, UV-Vis characterization of the Co(II)-P<sub>4</sub> complexes was performed and 585–635 nm <em>d-d</em> transition bands were observed as the characteristic complexation bands of the tertiary amine groups of P<sub>4</sub> with Co(II) ions. Obtained Co(II)-P<sub>4</sub> complexes might be considered for the development of magnetic resonance image (MRI) improvers or MRI contrast agents.</p><p class="Abstract"><span lang="EN-US"><br /></span></p>

Titration Simulations for Understanding of the Binding Equilibrium

2020 ◽  
Author(s):  
Dae Hyup Sohn
Keyword(s):  
Equilibrium Model ◽  
Binding Sites ◽  
Binding Constants ◽  
Reliability Evaluation ◽  
Binding Isotherm ◽  
Guest Chemistry

<p>The reliability evaluation of the predicted binding constants in numerous models is also a challenge for supramolecular host-guest chemistry. Here, I briefly formulate binding isotherm with the derivation of the multivalent equilibrium model for the chemist who wants to determine the binding constants of their compounds. This article gives an in-depth understanding of the stoichiometry of binding equilibrium to take divalent binding equilibria bearing two structurally identical binding sites as an example. The stoichiometry of binding equilibrium is affected by (1) the cooperativity of complex, (2) the concentration of titration media, and (3) the equivalents of guests. The simulations were conducted with simple Python codes.</p>

A Boronic Acid-Based Fluorescence Hydrogel for Monosaccharide Detection

2018 ◽  
Author(s):  
Suying Xu ◽  
Adam Sedgwick ◽  
Souad Elfecky ◽  
Wenbo Chen ◽  
Ashley Jones ◽  
...  
Keyword(s):  
Fluorescent Probe ◽  
Boronic Acid ◽  
Binding Constants ◽  
Strong Fluorescence ◽  
Fluorescence Response ◽  
Turn On ◽  
Fluorescence Turn On ◽  
Hydrogel System

<p>A boronic acid-based anthracene fluorescent probe was functionalised with an acrylamide unit to incorporate into a hydrogel system for monosaccharide detection<i>. </i>In solution, the fluorescent probe<b> </b>displayed a strong fluorescence turn-on response upon exposure to fructose, and an expected trend in apparent binding constants, as judged by a fluorescence response where D-fructose > D-galactose > D-mannose > D-glucose. The hydrogel incorporating the boronic acid monomer demonstrated the ability to detect monosaccharides by fluorescence with the same overall trend as the monomer in solution with the addition of fructose resulting in a 10-fold enhancement (≤ 0.25 M). <b><u></u></b></p>

(Thio)Urea-Functionalized Cavitands as Excellent Receptors for Organic Anions in Polar Media

2004 ◽  
Vol 69 (5) ◽  
pp. 1137-1148 ◽  
Author(s):  
Gennady V. Oshovsky ◽  
Willem Verboom ◽  
David N. Reinhoudt
Keyword(s):  
Binding Sites ◽  
Binding Constants ◽  
Organic Anions ◽  
Isothermal Microcalorimetry ◽  
Polar Media

Ureidocavitand 1 and thioureidocavitand 2 bind in CH3CN organic anions such as acetate, propionate, butyrate, etc. with K values of 2-8 × 105 l mol-1 and 2-9 × 106 l mol-1, respectively, as was determined with isothermal microcalorimetry (ITC). Bringing together four (thio)urea binding sites on a molecular platform gives rise to about 2000 times higher binding constants, compared with those of the corresponding single binding sites. Glucose- and galactose-containing thioureidocavitands 5 and 6 bind acetate in 1:1 CH3CN/water with a K-value of 2.15 × 103 l mol-1.

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