scholarly journals Spectroscopic and Colorimetric Studies for Anions with a New Urea-Based Molecular Cleft

Chemosensors ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 287
Author(s):  
Sanchita Kundu ◽  
Tochukwu Kevin Egboluche ◽  
Zehra Yousuf ◽  
Md. Alamgir Hossain
Keyword(s):  
Hydrogen Bonding ◽  
Binding Affinity ◽  
1H Nmr ◽  
Color Change ◽  
Dihydrogen Phosphate ◽  
Hydrogen Sulfate ◽  
Hydrogen Bonding Interactions

A new simple urea-based dipodal molecular cleft (L) has been synthesized and studied for its binding affinity for a variety of anions by 1H-NMR, UV-Vis and colorimetric techniques in DMSO-d6 and DMSO, respectively. The results from titration studies suggest that the receptor forms a 1:2 complex with each of the anions used via hydrogen bonding interactions and exhibits strong selectivity for fluoride among halides, showing the binding affinity in the order of fluoride > chloride > bromide > iodide; meanwhile, it displays moderate selectivity for acetate among oxoanions, showing the binding affinity in the order of acetate > dihydrogen phosphate > bicarbonate > hydrogen sulfate > nitrate. Colorimetric studies of L for anions in DMSO reveal that the receptor is capable of detecting fluoride, acetate, bicarbonate and dihydrogen phosphate, displaying a visible color change in the presence of the respective anions.

scholarly journals Anion Binding Studies of Urea and Thiourea Functionalized Molecular Clefts

2021 ◽  
Vol 8 ◽  
Author(s):  
Utsab Manna ◽  
Bobby Portis ◽  
Tochukwu K. Egboluche ◽  
Muhammad Nafis ◽  
Md. Alamgir Hossain
Keyword(s):  
Hydrogen Bonding ◽  
Functional Groups ◽  
Color Change ◽  
Anion Binding ◽  
Dihydrogen Phosphate ◽  
Hydrogen Sulfate ◽  
Binding Studies ◽  
Hydrogen Bonding Interactions ◽  
Distinct Color ◽  
Molecular Clefts

Two rationally designed 4-nitrophenyl-based molecular clefts functionalized with thiourea (L1) and urea (L2) have been synthesized and studied for a variety of anions by UV-Vis and colorimetric techniques in DMSO. Results from the binding studies suggest that both L1 and L2 bind halides showing the order: fluoride > chloride > bromide > iodide; and oxoanions showing the order: dihydrogen phosphate > hydrogen sulfate > nitrate > perchlorate. Each receptor has been shown to form a 1:1 complex with an anion via hydrogen bonding interactions, displaying distinct color change for fluoride and dihydrogen phosphate in solution. As compared to the urea-based receptor L2, the thiourea-based receptor L1 exhibits stronger affinity for anions due the presence of more acidic thiourea functional groups.

scholarly journals A Quinoline Based bis-Urea Receptor for Anions: A Selective Receptor for Hydrogen Sulfate

2012 ◽  
Vol 7 (3) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Tiffany H. Russ ◽  
Avijit Pramanik ◽  
Maryam E. Khansari ◽  
Bryan M. Wong ◽  
Alamgir Hossain
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Anion Binding ◽  
Dihydrogen Phosphate ◽  
Theoretical Studies ◽  
Hydrogen Sulfate ◽  
Binding Ability ◽  
Functional Theory ◽  
High Affinity ◽  
Hydrogen Bonding Interactions

A dipodal bis-urea receptor has been synthesized from the reaction of 8-amino quinoline and 1,4-phenylene diisocyanate in dichloromethane, and the anion binding ability of the receptor has been studied using fluoride, chloride, bromide, iodide, perchlorate, nitrate, dihydrogen phosphate and hydrogen sulfate by UV-Vis titrations in DMSO. The results show that the receptor binds each of the anions with a 1:1 stoichiometry, showing high affinity and moderate selectivity for hydrogen sulfate among the anions studied. Ab initio calculations based on density functional theory (DFT) suggest that an anion (X-) is bonded within the cleft formed by the two arms of the receptor through two NH…X- and two aromatic CH…X- interactions. The results from solution and theoretical studies suggest that binding is predominantly influenced by hydrogen bonding interactions and the basicity of anions.

scholarly journals E484K and N501Y SARS-CoV 2 Spike Mutants Increase ACE2 Recognition but Reduce Affinity for Neutralizing Antibody

2021 ◽  
Author(s):  
Sandipan Chakraborty
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Binding Affinity ◽  
Selection Pressure ◽  
Neutralizing Antibody ◽  
Salt Bridge ◽  
Receptor Affinity ◽  
Hydrogen Bonding Interactions ◽  
Π Stacking

SARS-CoV2 mutants emerge as variants of concern (VOC) due to altered selection pressure and rapid replication kinetics. Among them, lineages B.1.1.7, B.1.351, and P.1 contain a key mutation N501Y. B.1.135 and P.1 lineages have another mutation, E484K. Here, we decode the effect of these two mutations on the host receptor, ACE2, and neutralizing antibody (B38) recognition. The gain in binding affinity for the N501Y RBD mutant to the ACE2 is attributed to improved π-π stacking and π-cation interactions. The enhanced receptor affinity of the E484K mutant is caused due to the formation of a specific hydrogen bond and salt-bridge interaction with Glu75 of ACE2. Notably, both the mutations reduce the binding affinity for B38 due to the loss of several hydrogen-bonding interactions. The insights obtained from the study are crucial to interpret the increased transmissibility and reduction in the neutralization efficacy of rapidly emerging SARS-CoV2 VOCs.

Theoretical study of hydrogen bonding interactions in substituted nitroxide radicals

2021 ◽  
Author(s):  
Thufail M. Ismail ◽  
Neetha Mohan ◽  
P. K. Sajith
Keyword(s):  
Hydrogen Bonding ◽  
Interaction Energy ◽  
Electrostatic Potential ◽  
Molecular Electrostatic Potential ◽  
Theoretical Study ◽  
Nitroxide Radicals ◽  
Hydrogen Bonding Interactions ◽  
Bonded Complexes ◽  
Hydrogen Bonded

Interaction energy (Eint) of hydrogen bonded complexes of nitroxide radicals can be assessed in terms of the deepest minimum of molecular electrostatic potential (Vmin).

scholarly journals Circular linkage of intramolecular multi-hydrogen bonding frameworks through nucleophilic substitutions of β-dicarbonyls onto cyanuric chloride and subsequent tautomerisation

RSC Advances ◽  
2020 ◽  
Vol 10 (64) ◽  
pp. 39033-39036
Author(s):  
Ayano Awatani ◽  
Masaaki Suzuki
Keyword(s):  
Hydrogen Bonding ◽  
Cyanuric Chloride ◽  
Nucleophilic Substitutions ◽  
Hydrogen Bonding Interactions ◽  
Triazine Derivatives

Triply β-dicarbonyl-embedded 1,3,5-triazine derivatives result in formation of circular linkage of resonance-assisted hydrogen bonding interactions, which can be regarded as well-delocalized resonance hybrids.

Selective Hydrogen Bonding Controls Temperature Response of Layer-by-Layer Upper Critical Solution Temperature Micellar Assemblies

Soft Matter ◽  
2021 ◽  
Author(s):  
Aliaksei Aliakseyeu ◽  
Victoria Albright ◽  
Danielle Yarbrough ◽  
Samantha Hernandez ◽  
Qing Zhou ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Methacrylic Acid ◽  
Temperature Response ◽  
Solution Temperature ◽  
Layer By Layer ◽  
Critical Solution Temperature ◽  
Hydrogen Bonding Interactions ◽  
Upper Critical Solution Temperature ◽  
Lbl Films

This work establishes a correlation between the selectivity of hydrogen-bonding interactions and the functionality of micelle-containing layer-by-layer (LbL) assemblies. Specifically, we explore LbL films formed by assembly of poly(methacrylic acid)...

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