Experimental and Theoretical Evidence of the Bidentate Binding Mode of Dichloroacetamido Groups at the Upper Rim of Calix[4]arene Hydrogen-Bonding Anion Receptors

2004 ◽  
Vol 69 (5) ◽  
pp. 1063-1079 ◽  
Author(s):  
Alessandro Casnati ◽  
Francesca Bonetti ◽  
Francesco Sansone ◽  
Franco Ugozzoli ◽  
Rocco Ungaro

Calix[4]arenes in the 1,3-alternate conformation (1-3) and bearing activated amide groups at the upper rim have been synthesized and their anion binding properties studied and compared with conformationally mobile (4) or cone (Ib) receptors having the same binding groups. Association constants determined in CDCl3 show a stronger complexation for Y-shaped carboxylate anions and a higher efficiency for receptors (Ib and 3) bearing dichloroacetamido moieties as hydrogen bonding donor groups. Molecular modeling studies performed on the cone derivative (Ib) and its 1,3-alternate isomer (10) and ab initio calculations on 4-methoxyaniline derivatives (11-13) used as simplified models, reveal that the α,α-dichloroacetamido moieties bind anions in a bidentate fashion using both the N-H and the CHCl2 as hydrogen bonding donor groups. This explains the higher efficiency in carboxylate binding found for Ib and 3 that incorporate the dichloroacetamido binding unit in their structures.

2004 ◽  
Vol 82 (3) ◽  
pp. 454-460 ◽  
Author(s):  
Zhen-Ya Zeng ◽  
Yong-Bing He ◽  
Lan-Hua Wei ◽  
Jin-Long Wu ◽  
Yan-Yan Huang ◽  
...  

Two new neutral receptors (1 and 2) containing thiourea and amide groups were synthesized by simple steps in good yields. The binding properties of 1 and 2 with anions were examined by UV–vis, fluorescence, and 1H NMR spectroscopy. Receptor 1 had a better AcO–: H2PO4– selectivity in comparison with that for receptor 2. The association constants of 1·AcO–, 2·AcO–, and 2·H2PO4– were higher in comparison with those of other anions (Cl–, Br–, I–, p-NO2PhO–, and p-NO2PhOPO32–). In particular, a clear color change was observed, from pale yellow to red-brown, upon addition of AcO– to the solution of 1 in DMSO. The UV–vis and fluorescence data indicate that a 1:1 stoichiometry complex is formed between compound 1 or 2 and anions through hydrogen-bonding interactions.Key words: neutral receptors, anion recognition, synthesis, hydrogen bonds.


1999 ◽  
Vol 1 (8) ◽  
pp. 1217-1220 ◽  
Author(s):  
José L. Jiménez Blanco ◽  
Juan M. Benito ◽  
Carmen Ortiz Mellet ◽  
José M. García Fernández

RSC Advances ◽  
2017 ◽  
Vol 7 (19) ◽  
pp. 11253-11258 ◽  
Author(s):  
Sheila Ruiz-Botella ◽  
Pietro Vidossich ◽  
Gregori Ujaque ◽  
Eduardo Peris ◽  
Paul D. Beer

The preparation and anion binding properties of 1,3,5-tri-substituted benzene platform-based tripodal receptors containing halogen bonding (XB) iodo-imidazolium and iodo-triazolium motifs, and hydrogen bonding (HB) analogues are described.


1998 ◽  
Vol 45 (1) ◽  
pp. 221-231 ◽  
Author(s):  
J Brzeski ◽  
T Grycuk ◽  
A W Lipkowski ◽  
W Rudnicki ◽  
B Lesyng ◽  
...  

The binding properties of the SPXK- and APXK-type peptides to the AT-rich DNA fragments of different length were studied by measuring the competition of peptides with Hoechst 33258 dye for DNA binding and by the gel shift assay analysis. In parallel to the experimental studies, molecular modeling techniques were used to analyze possible binding modes of the SPXZ and APXK motifs to the AT-rich DNA. The results of the competition measurements and gel shift assays suggest that serine at the i-1 position (i is proline) can be replaced by alanine without affecting the binding properties of the motif. Thus, the presence of the conserved serine in this motif in many DNA-binding proteins is probably not dictated by structural requirements. Based on the results of molecular modeling studies we propose that the binding mode of the SPXK-type motifs to the AT-rich DNA resembles closely that between the N-terminal arm of the homeodomain and DNA. This model confirms that serine in the SPXK motifs is not essential for the DNA binding. The model also indicates that if X in the motif is glutamic acid, this residue is probably protonated in the complex with DNA.


2016 ◽  
Vol 20 (08n11) ◽  
pp. 950-965 ◽  
Author(s):  
Flávio Figueira ◽  
João M.M. Rodrigues ◽  
Andreia A.S. Farinha ◽  
José A.S. Cavaleiro ◽  
João P.C. Tomé

Over the last two decades the preparation of pyrrole-based receptors for anion recognition has attracted considerable attention. In this regard porphyrins, phthalocyanines and expanded porphyrins have been used as strong and selective receptors while the combination of those with different techniques and materials can boost their applicability in different applications as chemosensors and extracting systems. Improvements in the field, including the synthesis of this kind of compounds, can contribute to the development of efficient, cheap, and easy-to-prepare anion receptors. Extensive efforts have been made to improve the affinity and selectivity of these compounds and the continuous expansion of related research makes this chemistry even more promising. In this review, we summarize the most recent developments in anion binding studies while outlining the strategies that may be used to synthesize and functionalize these type of macrocycles.


RSC Advances ◽  
2016 ◽  
Vol 6 (40) ◽  
pp. 33880-33887 ◽  
Author(s):  
S. Byrne ◽  
K. M. Mullen

Herein we report the development of a new series of surface bound triazolium based anion sensors. Differences in the chemical reactivity and anion binding properties were observed; highlighting the need for good surface characterisation techniques such as HR MAS NMR.


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