scholarly journals Highly Sensitive and Selective Fluorescent Probes for Cu(II) Detection Based on Calix[4]arene-Oxacyclophane Architectures

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2456
Author(s):  
Alexandra I. Costa ◽  
Patrícia D. Barata ◽  
Carina B. Fialho ◽  
José V. Prata
Keyword(s):  
Conjugated Polymers ◽  
Fluorescent Probes ◽  
Density Functional ◽  
Inclusion Complexation ◽  
Copper Ion ◽  
Molecular Probe ◽  
Quantum Yields ◽  
Probe Display ◽  
Electron Transfer Mechanism ◽  
Vis Spectroscopy

A new topological design of fluorescent probes for sensing copper ion is disclosed. The calix[4]arene-oxacyclophane (Calix-OCP) receptor, either wired-in-series in arylene-alt-ethynylene conjugated polymers or standing alone as a sole molecular probe, display a remarkable affinity and selectivity for Cu(II). The unique recognition properties of Calix-OCP system toward copper cation stem from its pre-organised cyclic array of O-ligands at the calixarene narrow rim, which is kept in a conformational rigid arrangement by a tethered oxacyclophane sub-unit. The magnitude of the binding constants (Ka = 5.30 − 8.52 × 104 M−1) and the free energy changes for the inclusion complexation (−ΔG = 27.0 − 28.1 kJmol−1), retrieved from fluorimetric titration experiments, revealed a high sensitivity of Calix-OCP architectures for Cu(II) species. Formation of supramolecular inclusion complexes was evidenced from UV-Vis spectroscopy. The new Calix-OCP-conjugated polymers (polymers 4 and 5), synthesized in good yields by Sonogashira–Hagihara methodologies, exhibit high fluorescence quantum yields (ΦF = 0.59 − 0.65). Density functional theory (DFT) calculations were used to support the experimental findings. The fluorescence on–off behaviour of the sensing systems is tentatively explained by a photoinduced electron transfer mechanism.

Improving peroxymonosulfate activation by copper ion-saturated adsorbent-based single atom catalysts for the degradation of organic contaminants: electron-transfer mechanism and the key role of Cu single atoms

2021 ◽  
Author(s):  
Jingwen Pan ◽  
Baoyu Gao ◽  
Pijun Duan ◽  
Kangying Guo ◽  
Muhammad Akram ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Organic Contaminants ◽  
High Salinity ◽  
Copper Ion ◽  
Single Atom ◽  
Electron Transfer Mechanism ◽  
Persulfate Oxidation ◽  
Single Atoms ◽  
Oxidation Technology

Nonradical pathway-based persulfate oxidation technology is considered to be a promising method for high-salinity organic wastewater treatment.

scholarly journals Solution-Processed OLEDs Based on Thermally Activated Delayed Fluorescence Copper(I) Complexes with Intraligand Charge-Transfer Excited State

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1125
Author(s):  
Teng Teng ◽  
Jinfan Xiong ◽  
Gang Cheng ◽  
Changjiang Zhou ◽  
Xialei Lv ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Density Functional ◽  
Delayed Fluorescence ◽  
Quantum Yields ◽  
Functional Theory ◽  
Solution Processed ◽  
Thermally Activated Delayed Fluorescence ◽  
Light Emitting ◽  
Thermally Activated ◽  
Wide Range

A new series of tetrahedral heteroleptic copper(I) complexes exhibiting efficient thermally-activated delayed fluorescence (TADF) in green to orange electromagnetic spectral regions has been developed by using D-A type N^N ligand and P^P ligands. Their structures, electrochemical, photophysical, and electroluminescence properties have been characterized. The complexes exhibit high photoluminescence quantum yields (PLQYs) of up to 0.71 at room temperature in doped film and the lifetimes are in a wide range of 4.3–24.1 μs. Density functional theory (DFT) calculations on the complexes reveal the lowest-lying intraligand charge-transfer excited states that are localized on the N^N ligands. Solution-processed organic light emitting diodes (OLEDs) based on one of the new emitters show a maximum external quantum efficiency (EQE) of 7.96%.

scholarly journals Ultrafast proton release reaction and primary photochemistry of phycocyanobilin in solution observed with fs-time-resolved mid-IR and UV/Vis spectroscopy

2021 ◽  
Author(s):  
Maximilian Theiß ◽  
Merten Grupe ◽  
Tilman Lamparter ◽  
Maria Andrea Mroginski ◽  
Rolf Diller
Keyword(s):  
Density Functional ◽  
Transient Absorption ◽  
Vibrational Analysis ◽  
Density Functional Theory Calculations ◽  
Chem Phys ◽  
Molecular Structures ◽  
Ir Absorption ◽  
Time Resolved ◽  
Time Constants ◽  
Vis Spectroscopy

AbstractDeactivation processes of photoexcited (λex = 580 nm) phycocyanobilin (PCB) in methanol were investigated by means of UV/Vis and mid-IR femtosecond (fs) transient absorption (TA) as well as static fluorescence spectroscopy, supported by density-functional-theory calculations of three relevant ground state conformers, PCBA, PCBB and PCBC, their relative electronic state energies and normal mode vibrational analysis. UV/Vis fs-TA reveals time constants of 2.0, 18 and 67 ps, describing decay of PCBB*, of PCBA* and thermal re-equilibration of PCBA, PCBB and PCBC, respectively, in line with the model by Dietzek et al. (Chem Phys Lett 515:163, 2011) and predecessors. Significant substantiation and extension of this model is achieved first via mid-IR fs-TA, i.e. identification of molecular structures and their dynamics, with time constants of 2.6, 21 and 40 ps, respectively. Second, transient IR continuum absorption (CA) is observed in the region above 1755 cm−1 (CA1) and between 1550 and 1450 cm−1 (CA2), indicative for the IR absorption of highly polarizable protons in hydrogen bonding networks (X–H…Y). This allows to characterize chromophore protonation/deprotonation processes, associated with the electronic and structural dynamics, on a molecular level. The PCB photocycle is suggested to be closed via a long living (> 1 ns), PCBC-like (i.e. deprotonated), fluorescent species.

scholarly journals A theoretical and experimental study of the adsorptive removal of hexavalent chromium ions using graphene oxide as an adsorbent

2020 ◽  
Vol 18 (1) ◽  
pp. 936-942
Author(s):  
Ardhmeri Alija ◽  
Drinisa Gashi ◽  
Rilinda Plakaj ◽  
Admir Omaj ◽  
Veprim Thaçi ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Hexavalent Chromium ◽  
Adsorption Energy ◽  
Density Functional ◽  
Noncovalent Interactions ◽  
Theoretical Calculations ◽  
Chemical Oxidation ◽  
Chromium Ions ◽  
Adsorption Sites ◽  
Vis Spectroscopy

AbstractThis study is focused on the adsorption of hexavalent chromium ions Cr(vi) using graphene oxide (GO). The GO was prepared by chemical oxidation (Hummers method) of graphite particles. The synthesized GO adsorbent was characterized by Fourier transform infrared spectroscopy and UV-Vis spectroscopy. It was used for the adsorption of Cr(vi) ions. The theoretical calculations based on density functional theory and Monte Carlo calculations were used to explore the preferable adsorption site, interaction type, and adsorption energy of GO toward the Cr(vi) ions. Moreover, the most stable adsorption sites were used to calculate and plot noncovalent interactions. The obtained results are important as they give molecular insights regarding the nature of the interaction between GO surface and the adsorbent Cr(vi) ions. The found adsorption energy of −143.80 kcal/mol is indicative of the high adsorptive tendency of this material. The adsorption capacity value of GO toward these ions is q = 240.361 mg/g.

scholarly journals Transparent Ion-Exchange Membrane Exhibiting Intense Emission under a Specific pH Condition Based on Polypyridyl Ruthenium(II) Complex with Two Imidazophenanthroline Groups

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 400
Author(s):  
Hajime Kamebuchi ◽  
Satoshi Tamaki ◽  
Atsushi Okazawa ◽  
Norimichi Kojima
Keyword(s):  
Ion Exchange ◽  
Emission Intensity ◽  
Density Functional ◽  
Emission Spectra ◽  
Density Functional Theory Calculations ◽  
Ion Exchange Membrane ◽  
Quantum Yields ◽  
Relative Emission Intensity ◽  
Nafion Film ◽  
Exchange Membrane

The development and the photophysical behavior of a transparent ion-exchange membrane based on a pH-sensitive polypyridyl ruthenium(II) complex, [(bpy)2RuII(H2bpib)RuII(bpy)2](ClO4)4 (bpy = 2,2′-bipyridine, H2bpib = 1,4-bis([1,10]phenanthroline[5,6-d]-imidazol-2-yl)benzene), are experimentally and theoretically reported. The emission spectra of [(bpy)2RuII(H2bpib)RuII(bpy)2]@Nafion film were observed between pH 2 and pH 11 and showed the highest relative emission intensity at pH 5 (λmaxem = 594.4 nm). The relative emission intensity of the film significantly decreased down to 75% at pH 2 and 11 compared to that of pH 5. The quantum yields (Φ) and lifetimes (τ) showed similar correlations with respect to pH, Φ = 0.13 and τ = 1237 ns at pH 5, and Φ = 0.087 and τ = 1014 ns and Φ = 0.069 and τ = 954 ns at pH 2 and pH 11, respectively. These photophysical data are overall considerably superior to those of the solution, with the radiative- (kr) and non-radiative rate constants (knr) at pH 5 estimated to be kr = 1.06 × 105 s−1 and knr = 7.03 × 105 s−1. Density functional theory calculations suggested the contribution of ligand-to-ligand- and intraligand charge transfer to the imidazolium moiety in Ru-H3bpib species, implying that the positive charge on the H3bpib ligand works as a quencher. The Ru-Hbpib species seems to enhance non-radiative deactivation by reducing the energy of the upper-lying metal-centered excited state. These would be responsible for the pH-dependent “off-on-off” emission behavior.

scholarly journals Spectroscopic, X-ray Diffraction and Density Functional Theory Study of Intra- and Intermolecular Hydrogen Bonds in Ortho-(4-tolylsulfonamido)benzamides

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 926
Author(s):  
Malose J. Mphahlele ◽  
Eugene E. Onwu ◽  
Marole M. Maluleka
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Hydrogen Bonds ◽  
Density Functional ◽  
Tetrahedral Geometry ◽  
Hindered Rotation ◽  
Hydrogen Bond Acceptor ◽  
Functional Theory ◽  
Vis Spectroscopy ◽  
Hydrogen Bonded

The conformations of the title compounds were determined in solution (NMR and UV-Vis spectroscopy) and in the solid state (FT-IR and XRD), complemented with density functional theory (DFT) in the gas phase. The nonequivalence of the amide protons of these compounds due to the hindered rotation of the C(O)–NH2 single bond resulted in two distinct resonances of different chemical shift values in the aromatic region of their 1H-NMR spectra. Intramolecular hydrogen bonding interactions between the carbonyl oxygen and the sulfonamide hydrogen atom were observed in the solution phase and solid state. XRD confirmed the ability of the amide moiety of this class of compounds to function as a hydrogen bond acceptor to form a six-membered hydrogen bonded ring and a donor simultaneously to form intermolecular hydrogen bonded complexes of the type N–H···O=S. The distorted tetrahedral geometry of the sulfur atom resulted in a deviation of the sulfonamide moiety from co-planarity of the anthranilamide scaffold, and this geometry enabled oxygen atoms to form hydrogen bonds in higher dimensions.

scholarly journals Nitrile-Substituted 2-(Oxazolinyl)-Phenols: Minimalistic Excited-State Intramolecular Proton Transfer (ESIPT)-Based Fluorophores

2020 ◽  
Author(s):  
Dominik Göbel ◽  
Daniel Duvinage ◽  
Tim Stauch ◽  
Boris Nachtsheim
Keyword(s):  
Excited State ◽  
Solid State ◽  
Proton Transfer ◽  
Density Functional ◽  
Intramolecular Proton Transfer ◽  
Crystal Structure Analysis ◽  
Quantum Yields ◽  
Functional Theory ◽  
Emission Properties ◽  
Emission Enhancement

Herein, we present minimalistic single-benzene, excited-state intramolecular proton transfer (ESIPT) based fluorophores as powerful solid state emitters. The very simple synthesis gave access to all four regioisomers of nitrile-substituted 2(oxazolinyl)phenols (MW = 216.1). In respect of their emission properties they can be divided into aggregation-induced emission enhancement (AIEE) luminophores (1-CN and 2-CN), dual state emission (DSE) emitters (3-CN) and aggregation-caused quenching (ACQ) fluorophores (4‐CN). Remarkably, with compound 1-CN we discovered a minimalistic ESIPT based fluorophore with extremely high quantum yield in the solid state ΦF = 87.3% at λem = 491 nm. Furthermore, quantum yields in solution were determined up to ΦF = 63.0%, combined with Stokes shifts up till 11.300 cm–1. Temperature dependent emission mapping, crystal structure analysis and time-dependent density functional theory (TDDFT) calculations gave deep insight into the origin of the emission properties.<br>

scholarly journals 1,3,4-Thiadiazole-Containing Azo Dyes: Synthesis, Spectroscopic Properties and Molecular Structure

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2822
Author(s):  
Agnieszka Kudelko ◽  
Monika Olesiejuk ◽  
Marcin Luczynski ◽  
Marcin Swiatkowski ◽  
Tomasz Sieranski ◽  
...  
Keyword(s):  
Azo Dyes ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Spectroscopic Properties ◽  
Radiation Absorption ◽  
Functional Theory ◽  
Chemical Structures ◽  
Vis Spectroscopy ◽  
High Yields

Three series of azo dyes derived from 2-amino-5-aryl-1,3,4-thiadiazoles and aniline, N,N-dimethylaniline and phenol were synthesized in high yields by a conventional diazotization-coupling sequence. The chemical structures of the prepared compounds were confirmed by 1H-NMR, 13C-NMR, IR, UV-Vis spectroscopy, mass spectrometry and elemental analysis. In addition, the X-ray single crystal structure of a representative azo dye was presented. For explicit determination of the influence of a substituent on radiation absorption in UV-Vis range, time-dependent density functional theory calculations were performed.

scholarly journals DFT Prediction of Factors Affecting the Structural Characteristics, the Transition Temperature and the Electronic Density of Some New Conjugated Polymers

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1207
Author(s):  
Quoc-Trung Vu ◽  
Thi-Thuy-Duong Tran ◽  
Thuy-Chinh Nguyen ◽  
Thien Vuong Nguyen ◽  
Hien Nguyen ◽  
...  
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Conjugated Polymers ◽  
Bond Length ◽  
Density Functional ◽  
Structural Characteristics ◽  
Side Chain ◽  
Electronic Density ◽  
Energy Field ◽  
Energy Bandgap

Conjugated polymers are promising materials for various cutting-edge technologies, especially for organic conducting materials and in the energy field. In this work, we have synthesized a new conjugated polymer and investigated the effect of distance between bond layers, side-chain functional groups (H, Br, OH, OCH3 and OC2H5) on structural characteristics, phase transition temperature (T), and electrical structure of C13H8OS using Density Functional Theory (DFT). The structural characteristics were determined by the shape, network constant (a, b and c), bond length (C–C, C–H, C–O, C–S, C–Br and O–H), phase transition temperatures, and the total energy (Etot) on a base cell. Our finding shows that the increase of layer thickness (h) of C13H8OS–H has a negligible effect on the transition temperature, while the energy bandgap (Eg) increases from 1.646 eV to 1.675 eV. The calculation of bond length with different side chain groups was carried out for which C13H8OS–H has C–H = 1.09 Å; C13H8OS–Br has C–Br = 1.93 Å; C13H8OS–OH has C–O = 1.36 Å, O–H = 0.78 Å; C13H8OS–OCH3 has C–O = 1.44 Å, O–H =1.10 Å; C13H8OS–OC2H5 has C–O = 1.45 Å, C–C = 1.51Å, C–H = 1.10 Å. The transition temperature (T) for C13H8OS–H was 500 K < T < 562 K; C13H8OS–Br was 442 K < T < 512 K; C13H8OS–OH was 487 K < T < 543 K; C13H8OS–OCH3 was 492 K < T < 558 K; and C13H8OS–OC2H5 was 492 K < T < 572 K. The energy bandgap (Eg) of Br is of Eg = 1.621 eV, the doping of side chain groups H, OH, OCH3, and OC2H5, leads to an increase of Eg from 1.621 eV to 1.646, 1.697, 1.920, and 2.04 eV, respectively.

scholarly journals UV–Vis Absorption Properties of New Aromatic Imines and Their Compositions with Poly({4,8-bis[(2-Ethylhexyl)oxy]Benzo[1,2-b:4,5-b′]Dithiophene-2,6-diyl}{3-Fluoro-2-[(2-Ethylhexyl)Carbonyl]Thieno[3,4-b]Thiophenediyl})

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4191 ◽  
Author(s):  
Agnieszka Gonciarz ◽  
Robert Pich ◽  
Krzysztof Artur Bogdanowicz ◽  
Beata Jewloszewicz ◽  
Wojciech Przybył ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Organic Solar Cells ◽  
Density Functional ◽  
Bulk Heterojunction ◽  
Theoretical Calculations ◽  
Dft Methods ◽  
Functional Theory ◽  
Chemical Structures ◽  
Vis Spectroscopy ◽  
Aromatic Imines

In this paper, four new aromatic imines containing at least one thiazole-based heterocycle were analyzed in detail by UV–Vis spectroscopy, taking into consideration their chemical structures and interactions with PTB7, a known polymeric electron donor widely used in bulk heterojunction organic solar cells. It is demonstrated that the absorption spectra of the investigated active compositions can be modified not only by changing the chemical structure of imine, but also via formulations with PTB7. For all investigated imines and PTB7:imine compositions, calibration curves were obtained in order to find the optimum concentration in the composition with PTB7 for expansion and optimization of absorption spectra. All imines and PTB7:imine compositions were investigated in 1,2-dichlorobenzene by UV–Vis spectroscopy in various concentrations, monitoring the changes in the π–π* and n–π* transitions. With increasing imine concentrations, we did not observe changes in absorption maxima, while with increasing imine concentrations, a hypochromic effect was observed. Finally, we could conclude that all investigated compositions exhibited wide absorptions of up to 800 nm and isosbestic points in the range of 440–540 nm, confirming changes in the macromolecular organization of the tested compounds. The theoretical calculations of their vibration spectra (FTIR) and LUMO–HOMO levels by Density Functional Theory (DFT) methods are also provided. Finally, IR thermal images were measured for organic devices based on imines and the imine:PTB7 composite.

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