On the recognition of chloride, bromide and nitrate anions by anthracene–squaramide conjugated compounds: a computational perspective

Orenha, Renato Pereira; Silva, Vanessa Borges da; Caramori, Giovanni F.; Schneider, Felipe S. S.; Piotrowski, Maurício J.; Contreras‐García, Julia; Cárdenas, Carlos; Gonçalves, Marina Briese; Mendizábal, Fernando; Parreira, Renato L. T.

doi:10.1039/d0nj03685d

Cited by 9 publications

(15 citation statements)

References 57 publications

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“…As shown in table 1, receptors 2 and 4, bearing either a nitro ChemPhysChem substituent or two CF 3 groups respectively, turned out to be more efficient than ternary receptors 1 and 3,in good agreement with literature. [30,31] Strong electron withdrawing groups such as nitro or trifluoromethyl induce highest variation of chemical shifts of proton H a . A highest variation correlates with highest impact on association constants.…”

Section: Ground-state-binding Studies By Nmr Mass and Uv/vis Spectros...mentioning

confidence: 99%

Chloride Binding Modulated by Anion Receptors Bearing Tetrazine and Urea

et al. 2022

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Modulation and fine‐tuning of the strength of weak interactions to bind anions are described in a series of synthetic receptors. The general design of the receptors includes both a urea motif and a tetrazine motif. The synthetic sequence towards three receptors is detailed. Impacts of H‐bond strength and linker length between urea and tetrazine on chloride complexation are studied. Binding properties of the chloride anion are examined in both the ground and excited states using a panel of analytical methods (NMR spectroscopy, mass spectrometry, UV/Visible spectroscopies, and fluorescence). A ranking of the receptors by complexation strength has been determined, allowing a better understanding of the structure‐properties relationship on these compounds.

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Section: Ground-state-binding Studies By Nmr Mass and Uv/vis Spectros...mentioning

confidence: 99%

Chloride Binding Modulated by Anion Receptors Bearing Tetrazine and Urea

et al. 2022

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“…The significance of the electrostatic and orbital interactions in the selectivity was also recognized in the studies of other receptors, including pincer‐like molecules, [16k] self‐assembly receptors, [16j] as well as neutral [16b] and charged [16a] supramolecular cages. However, the host‐guest binding results from the competition between attractive forces and repulsive forces.…”

Section: Introductionmentioning

confidence: 89%

Selectivity Rule of Cryptands for Anions: Molecular Rigidity and Bonding Site

Wang

2023

Chemistry A European J

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Cryptands utilize inside CH or NH groups as hydrogen bond (H‐bond) donors to capture anions such as halides. In this work, the nature and selectivity of confined hydrogen bonds inside cryptands were computationally analyzed with the energy decomposition scheme based on the block‐localized wavefunction method (BLW‐ED), aiming at an elucidation of governing factors in the binding between cryptands and anions. It was revealed that the intrinsic strengths of inward hydrogen bonds are dominated by the electrostatic attraction, while the anion preferences (selectivity) of inner CH and NH hydrogen bonds are governed by the Pauli exchange repulsion and electrostatic interaction, respectively. Typical conformers of cages are classified into two groups, including the C3(h)‐symmetrical conformers, in which all halide anions are located near the centroids of cages, and the “semi‐open” conformers, which exhibit shifted bonding sites for different halide anions. Accordingly, the difference in governing factors of selectivity is attributed to either the rigidity of cages or the binding site of anions for these two groups. In details, the C3 conformers of NH cryptands can be enlarged more remarkably than the C3(h)‐symmetrical conformers of CH cryptands as the size of anion (ionic radius) increases, resulting in the relaxation of the Pauli repulsion and a dramatic reduction in electrostatic attraction, which eventually rules the selectivity of NH cryptands for halide anions. By contrary, the CH cryptands are more rigid and cannot effectively reduce the Pauli repulsion, which subsequently governs the anion preference. Unlike C3 conformers whose rigidity determines the selectivity, semi‐open conformers exhibit different binding sites for different anions. From F− to I−, the bonding site shifts toward the outside end of the pocket inside the semi‐open NH cryptand, leading to the significant reduction of the electrostatic interaction that dominates the anion preference. Differently, binding sites are much less affected by the size of anion inside the semi‐open CH cryptand, in which the Pauli exchange repulsion remains the key factor for the selectivity of inner hydrogen bonds.

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“…23 More recent studies have shown that the interaction between Cl − , Br − , and nitrate (NO 3 − ) anions and anthracene-conjugated SQs with −CF 3 and −NO 2 substituents, when analyzed computationally by energy decomposition analysis, is governed by a predominantly noncovalent process that generates attractive interaction energy consisting mainly of electrostatic energy and partly of orbital contribution. 29,32 Despite extensive anion-binding reports on SQs 15,18−33 with aromatic substituents, to the best of our knowledge, no systematic report on the investigation of the binding properties of anions on SQs with only aliphatic substitutions has been attempted before. The presence of aromatic substituents in the NH group in SQs may increase the anion-binding capacity; 15,18−33 however, anions might cause deprotonation by detaching protons from the NH of SQs depending on the substituent of the aromatic ring, 20,24,28 and their low solubility both in some organic solvents 20,24 and in water 28 leads to a lack of understanding of their actual effects against cells in in vitro studies.…”

Section: ■ Introductionmentioning

confidence: 99%

Anion-Binding Properties of Aliphatic Symmetric Squaramide Receptors

Mert,

Erdebil

2024

ACS Omega

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Squaramides (SQs), which are very popular for their Hbonding ability, have attracted great interest due to their wide range of applications such as asymmetric synthesis, pharmacology, and anion transportation. In this study, aliphatic symmetric SQs based on cis/trans-1,2-diaminocyclohexane (DACH) substituted with cyclic tertiary amines, synthesized in four steps under simple reaction conditions, were investigated for the first time for their ability to bind Cl − , Br − , and I − anions. The changes in cis/trans geometric isomers and the cyclic ring (pyrrolidine vs piperidine) were found to have a combined effect on the degree of anion binding. The spectroscopic titrations of the SQs with TBA-Cl, TBA-Br, and TBA-I in the range of 0.2 to 20.0 equiv were monitored by 1 H NMR, and the analyses of the magnitude of chemical shift differences in the NH peaks of the SQs in course of titration were performed by DynaFit and BindFit programs for the calculation of their K a values. All symmetric SQs I−IV were found to selectively bind Cl − anion more strongly than Br − anion to varying degrees depending on the SQ derivatives. Especially, SQ IV, which has a symmetric trans-DACH and a pyrrolidine ring, was found to have the highest Cl − anion-binding ability compared to the other SQs. However, the SQs did not show any change in the chemical shift of the NH proton in 1 H NMR upon successive addition of TBA-I, indicating that they do not interact with I − anion. The stoichiometries of the complexation behavior of SQs I−IV toward Cl − and Br − anions were also analyzed by Job plots.

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On the recognition of chloride, bromide and nitrate anions by anthracene–squaramide conjugated compounds: a computational perspective

Abstract: The anionic recognition area is applicable in several biological fields. Squaramide derived compounds appear as potential structures for recognize anions. Here, the bond mechanisms between the chloride (Cl–), bromide (Br–)...

Cited by 9 publications

References 57 publications

Chloride Binding Modulated by Anion Receptors Bearing Tetrazine and Urea

Chloride Binding Modulated by Anion Receptors Bearing Tetrazine and Urea

Selectivity Rule of Cryptands for Anions: Molecular Rigidity and Bonding Site

Anion-Binding Properties of Aliphatic Symmetric Squaramide Receptors

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