From one to three, modifications of sensing behavior with solvent system: DFT calculations and real-life application in detection of multianalytes (Cu2+, Ni2+ and Co2+) based on a colorimetric Schiff base probe

Pungut, Nur Amira Solehah; Heng, Mok Piew; Saad, Hazwani Mat; Sim, Kae Shin; Lee, Vannajan Sanghiran; Tan, Kong Wai

doi:10.1016/j.molstruc.2021.130453

“…The equilibrium constant for this two-step process was calculated following the methods described by Ramette et al [ 30 ]. The equilibrium constant (K eq = 1.67 × 10 −5 ) was evaluated using the fluorescence of PTP at 430 nm when Zn 2+ was gradually added to the PTP -fluoride adduct ( Supplementary Figure S11a,b ) [ 31 ].…”

Section: Resultsmentioning

confidence: 99%

“…The equilibrium constant for this two-step process was calculated following the methods described by Ramette et al [30]. The equilibrium constant (Keq = 1.67 × 10 −5 ) was evaluated using the fluorescence of PTP at 430 nm when Zn 2+ was gradually added to the PTP-fluoride adduct (Supplementary Figure S11a,b) [31]. Similar UV-Vis spectra were observed upon the respective addition of 5 equivalents of Ag + , Al 3+ , Cd 2+ , Co 2+ , Cr 3+ , Fe 3+ , Fe 2+ , Li + , Mg 2+ , and Ni 2+ (Supplementary Figure S4a).…”

Section: A Combination Of Ptp Tbaf and Zn 2+mentioning

confidence: 99%

1,2,3-Triazoles: Controlled Switches in Logic Gate Applications

Ghosh,

Atkinson,

Gibson

et al. 2023

Sensors

6

0

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A 1,2,3-triazole-based chemosensor is used for selective switching in logic gate operations through colorimetric and fluorometric response mechanisms. The molecular probe synthesized via “click chemistry” resulted in a non-fluorescent 1,4-diaryl-1,2,3-triazole with a phenol moiety (PTP). However, upon sensing fluoride, it TURNS ON the molecule’s fluorescence. The TURN-OFF order occurs through fluorescence quenching of the sensor when metal ions, e.g., Cu2+, and Zn2+, are added to the PTP-fluoride ensemble. A detailed characterization using Nuclear Magnetic Resonance (NMR) spectroscopy in a sequential titration study substantiated the photophysical characteristics of PTP through UV-Vis absorption and fluorescence profiles. A combination of fluorescence OFF-ON-OFF sequences provides evidence of 1,2,3-triazoles being controlled switches applicable to multimodal logic operations. The “INH” gate was constructed based on the fluorescence output of PTP when the inputs are F− and Zn2+. The “IMP” and “OR” gates were created on the colorimetric output responses using the probe’s absorption with multiple inputs (F− and Zn2+ or Cu2+). The PTP sensor is the best example of the “Write-Read-Erase-Read” mimic.

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“…P-Fe-TiO 2 -Cd, P-Fe-TiO 2 -Pb, and P-Fe-TiO 2 -Cd have a smaller energy gap between the HOMO and LUMO than does P-Fe-TiO 2 . A smaller energy gap indicates that the corresponding conjugate is more stable [48], which shows that the structure of P-Fe-TiO 2 is more stable after being combined with heavy metal ions. In addition, the Mulliken charge analysis proved that the best binding site for heavy metal ions is the O atom bridging P and Fe because it has the strongest negative charge (i.e., the O atom with a -0.791C charge in Figure 7(b), the O atom with a -0.772C charge in Figure 7(c), and the O atom with a -0.757C charge in Figure 7(d)) and has the greatest attraction to heavy metal ions (Zhang and Zheng et al, 2021b), as shown in Figure 7.…”

Section: Resultsmentioning

confidence: 99%

Electron-Scale Insights into the Single and Coadsorption Cd(II) Behaviors of a Metal-Nonmetal-Modified Titanium Dioxide

Ren

¹

,

Zheng

²

,

Yang

³

et al. 2021

Adsorption Science & Technology

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Metal (Fe) and nonmetal (P) were used to modify TiO2, and then, several functional groups such as P-O, P=O, Fe-O, and -OH were introduced on its surface to enhance the adsorption capacity for Cd(II), which could reach 121 mg/g. According to the experimental analysis of adsorption performance, chemical adsorption dominates the adsorption process, and the adsorption capacity increases with increasing temperature within a certain range. The results of competitive adsorption experiments showed that both Pb(II) and Cu(II) affect the adsorption of Cd(II) and that the adsorption order of P-Fe-TiO2 for heavy metal ions is Pb II > Cd II > Cu II . We further investigated the adsorption mechanism of P-Fe-TiO2 for Cd(II) and the reasons for the difference in competitive adsorption and used DFT calculations to confirm the experimental results. In the analysis of binding energy and frontier molecular orbitals (FMOs), we confirmed that charge transfer occurred during the adsorption process, so chemical reactions occurred. The binding energy of P-Fe-TiO2 and Pb(II) is the largest. The results of the competitive adsorption experiment also confirmed that the adsorbent has the greatest effect on Pb. Mulliken analysis was used to identify the best binding site on the adsorbent. The results of electrostatic potential, total potential, and differential charge analysis further prove the conclusions described above.

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“…Reaction between rhodamine B hydrazide and o -vanillin, instead of salicylaldehyde, produced compound 4 (Scheme 2), which was reported for the detection of multiple cations such as Cu 2+ , Ni 2+ and Co 2+ in DMSO/tris-sodium chloride buffer (2 : 1, v/v, pH 7.5). 17 The limit of detection values were determined to be 4.0 × 10 −8 M, 3.2 × 10 −7 M and 4.8 × 10 −7 M towards Cu 2+ , Ni 2+ and Co 2+ , respectively.…”

Section: Introductionmentioning

confidence: 91%