Fluorescence properties of p-tert-butyldihomooxacalix[4]arene derivatives and the effect of anion complexation

Miranda, Alexandre S.; Martelo, Liliana; Fedorov, Alexander; Berberan‐Santos, Mário N.; Marcos, Paula M.

doi:10.1039/c7nj00652g

Cited by 10 publications

(14 citation statements)

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“…The NO3- and HSO4- anion binding constants with CF 3 -Phurea 5b were also determined by fluorescence in CH 2 Cl 2 . The data obtained (log K ass : NO3- = 3.87 and HSO4- = 4.00) are higher, as expected, than those obtained for 5a (log K ass = 3.5 and 3.7) (Miranda et al, 2017), but follow the same trend. The results are also similar to those obtained by UV-Vis absorption (Table 3), indicating that fluorescence can also be a good method for the determination of the receptor-anion association constants.…”

Section: Resultssupporting

confidence: 81%

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Ditopic Receptors Based on Dihomooxacalix[4]arenes Bearing Phenylurea Moieties With Electron-Withdrawing Groups for Anions and Organic Ion Pairs

et al. 2019

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Two bidentate dihomooxacalix[4]arene receptors bearing phenylurea moieties substituted with electron-withdrawing groups at the lower rim via a butyl spacer (CF3-Phurea 5b and NO2 Phurea 5c) were obtained in the cone conformation in solution, as shown by NMR. The X-ray crystal structure of 5b is reported. The binding affinity of these receptors toward several relevant anions was investigated by 1H NMR, UV-Vis absorption in different solvents, and fluorescence titrations. Compounds 5b and 5c were also tested as ditopic receptors for organic ion pairs, namely monoamine neurotransmitters and trace amine hydrochlorides by 1H NMR studies. The data showed that both receptors follow the same trend and, in comparison with the unsubstituted phenylurea 5a, they exhibit a significant enhancement on their host-guest properties, owing to the increased acidity of their urea NH protons. NO2-Phurea 5c is the best anion receptor, displaying the strongest complexation for F−, closely followed by the oxoanions BzO−, AcO−, and HSO4-. Concerning ion pair recognition, both ditopic receptors presented an outstanding efficiency for the amine hydrochlorides, mainly 5c, with association constants higher than 109 M−2 in the case of phenylethylamine and tyramine.

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Section: Resultssupporting

confidence: 81%

“…Owing to the intrinsic fluorescence of receptors 5 , and to evaluate the changes caused by the introduction of the substituent groups at the p -position of the phenylurea ring, some photophysical properties of 5a and 5b were determined, following previous studies (Miranda et al, 2017).…”

Section: Resultsmentioning

confidence: 99%

Ditopic Receptors Based on Dihomooxacalix[4]arenes Bearing Phenylurea Moieties With Electron-Withdrawing Groups for Anions and Organic Ion Pairs

et al. 2019

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“…As part of our continuous interest on the host–guest properties of homooxacalixarenes (calixarene analogues in which the CH 2 bridges are partly or completely replaced by CH 2 OCH 2 groups) [ 21 , 22 ], we have reported the anion and ion pair recognition of several (thio)ureido-dihomooxacalix[4]arenes [ 23 , 24 , 25 ], including fluorescent receptors [ 26 , 27 ]. The ion affinity of hexahomotrioxacalix[3]arenes, a very interesting macrocycle formed by an 18-membered ring and having only two basic conformations, has also been investigated [ 28 , 29 , 30 , 31 , 32 , 33 ].…”

Section: Introductionmentioning

confidence: 99%

Anion Binding by Fluorescent Ureido-Hexahomotrioxacalix[3]arene Receptors: An NMR, Absorption and Emission Spectroscopic Study

Miranda

Marcos

Ascenso³

et al. 2022

Molecules

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Fluorescent receptors (4a–4c) based on (thio)ureido-functionalized hexahomotrioxacalix[3]arenes were synthesised and obtained in the partial cone conformation in solution. Naphthyl or pyrenyl fluorogenic units were introduced at the lower rim of the calixarene skeleton via a butyl spacer. The binding of biologically and environmentally relevant anions was studied with NMR, UV–vis absorption, and fluorescence titrations. Fluorescence of the pyrenyl receptor 4c displays both monomer and excimer fluorescence. The thermodynamics of complexation was determined in acetonitrile and was entropy-driven. Computational studies were also performed to bring further insight into the binding process. The data showed that association constants increase with the anion basicity, and AcO−, BzO− and F− were the best bound anions for all receptors. Pyrenylurea 4c is a slightly better receptor than naphthylurea 4a, and both are more efficient than naphthyl thiourea 4b. In addition, ureas 4a and 4c were also tested as ditopic receptors in the recognition of alkylammonium salts.

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“…As part of our on-going interest on the host-guest properties of substituted dihomooxacalix[4]arenes (calix[4]arene analogues in which one CH 2 bridge is replaced by one CH 2 OCH 2 group) with (thio)urea units [ 19 , 20 , 21 , 22 , 23 ], we have extended our research into the study of fluorescent receptors for anion [ 24 ] and ion-pair recognition. Thus, dihomooxacalix[4]arene-based fluorescent sensors bearing (thio)urea groups as a binding site and naphthalene moieties as a fluorophore unit were obtained for the first time.…”

Section: Introductionmentioning

confidence: 99%

Dihomooxacalix[4]arene-Based Fluorescent Receptors for Anion and Organic Ion Pair Recognition

et al. 2020

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Fluorescent dihomooxacalix[4]arene-based receptors 5a–5c, bearing two naphthyl(thio)ureido groups at the lower rim via a butyl spacer, were synthesised and obtained in the cone conformation in solution. The X-ray crystal structures of 1,3- (5a) and 3,4-dinaphthylurea (5b) derivatives are reported. Their binding properties towards several anions of different geometries were assessed by 1H-NMR, UV-Vis absorption and fluorescence titrations. Structural and energetic insights of the naphthylurea 5a and 5b complexes were also obtained using quantum mechanical calculations. The data showed that all receptors follow the same trend, the association constants increase with the anion basicity, and the strongest complexes were obtained with F−, followed by the oxoanions AcO− and BzO−. Proximal urea 5b is a better anion receptor compared to distal urea 5a, and both are more efficient than thiourea 5c. Compounds 5a and 5b were also investigated as heteroditopic receptors for biologically relevant alkylammonium salts, such as the neurotransmitter γ-aminobutyric acid (GABA·HCl) and the betaine deoxycarnitine·HCl. Chiral recognition towards the guest sec-butylamine·HCl was also tested, and a 5:2 selectivity for (R)-sec-BuNH3+·Cl− towards (P) or (M) enantiomers of the inherently chiral receptor 5a was shown. Based on DFT calculations, the complex [(S)-sec-BuNH3+·Cl−/(M)-5a] was indicated as the more stable.

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Fluorescence properties of p-tert-butyldihomooxacalix[4]arene derivatives and the effect of anion complexation

Abstract: The intrinsic electronic absorption and fluorescence properties of several dihomooxacalix[4]arenes are studied.

Cited by 10 publications

References 11 publications

Ditopic Receptors Based on Dihomooxacalix[4]arenes Bearing Phenylurea Moieties With Electron-Withdrawing Groups for Anions and Organic Ion Pairs

Ditopic Receptors Based on Dihomooxacalix[4]arenes Bearing Phenylurea Moieties With Electron-Withdrawing Groups for Anions and Organic Ion Pairs

Anion Binding by Fluorescent Ureido-Hexahomotrioxacalix[3]arene Receptors: An NMR, Absorption and Emission Spectroscopic Study

Dihomooxacalix[4]arene-Based Fluorescent Receptors for Anion and Organic Ion Pair Recognition

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