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Sanna Angotzi M, Mameli V, Khanal S, Veverka M, Vejpravova J, Cannas C. Effect of different molecular coatings on the heating properties of maghemite nanoparticles. NANOSCALE ADVANCES 2022; 4:408-420. [PMID: 35178500 PMCID: PMC8765356 DOI: 10.1039/d1na00478f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 11/08/2021] [Indexed: 05/04/2023]
Abstract
In this work, the effect of different molecular coatings on the alternating magnetic field-induced heating properties of 15 nm maghemite nanoparticles (NPs) in water dispersions was studied at different frequencies (159-782 kHz) and field amplitudes (100-400 G). The original hydrophobic oleate coating was replaced with dimercaptosuccinic acid (DMSA) or polyethylene glycol trimethoxysilane (PEGTMS), while cetrimonium bromide (CTAB) or stearic acid-poloxamer 188 (SA-P188) was intercalated or encapsulated, respectively, to transfer the dispersions into water. Surface modification, based on intercalation processes, induced clustering phenomena with the formation of spherical-like assemblies (CTAB and SA-P188), while ligand-exchange strategies kept the particles isolated. The clustering phenomenon has detrimental effects on the heating performances compared with isolated systems, in line with the reduction of Brown relaxation times. Furthermore, broader comprehension of the heating phenomenon in this dynamic system is obtained by following the evolution of SPA and ILP with time and temperature beyond the initial stage.
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Affiliation(s)
- Marco Sanna Angotzi
- Department of Chemical and Geological Sciences, University of Cagliari S.S. 554 Bivio per Sestu, Monserrato 09042 CA Italy
- Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM) Via Giuseppe Giusti 9 50121 Firenze (FI) Italy
| | - Valentina Mameli
- Department of Chemical and Geological Sciences, University of Cagliari S.S. 554 Bivio per Sestu, Monserrato 09042 CA Italy
- Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM) Via Giuseppe Giusti 9 50121 Firenze (FI) Italy
| | - Shankar Khanal
- Department of Condensed Matter Physics, Charles University Ke Karlovu 5 12116 Prague 2 Czech Republic
| | - Miroslav Veverka
- Department of Condensed Matter Physics, Charles University Ke Karlovu 5 12116 Prague 2 Czech Republic
| | - Jana Vejpravova
- Department of Condensed Matter Physics, Charles University Ke Karlovu 5 12116 Prague 2 Czech Republic
| | - Carla Cannas
- Department of Chemical and Geological Sciences, University of Cagliari S.S. 554 Bivio per Sestu, Monserrato 09042 CA Italy
- Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM) Via Giuseppe Giusti 9 50121 Firenze (FI) Italy
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Quantum chemical studies on structural, spectroscopic, nonlinear optical, and thermodynamic properties of the 1,2,4-triazole compound. HETEROCYCL COMMUN 2021. [DOI: 10.1515/hc-2020-0130] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Abstract
In this study, the structure of 4-[4-(diethylamino)-benzylideneamino]-5-benzyl-2H-1,2,4-triazol-3(4H)-one (DBT) was examined through spectroscopic and theoretical analyses. In this respect, the geometrical, vibrational frequency, 1H and 13C-nuclear magnetic resonance (NMR) chemical shifts, thermodynamic, hyperpolarizability, and electronic properties including the highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) energies of DBT as a potential non-linear optical (NLO) material were investigated using density functional theory at the B3LYP level with the 6-311G basis set. 1H and 13C-NMR chemical shifts of DBT with the gauge-invariant atomic orbital and continuous set of gauge transformation methods (in the solvents) were estimated, and the computed chemical shift values displayed excellent alignment with observed ones. Time-dependent density-functional theory (TD-DFT) calculations with the integral equation formalism polarizable continuum model within various solvents and gas phases in the ground state were used to evaluate UV-vis absorption and fluorescence emission wavelengths. Thermodynamic parameters including enthalpy, heat capacity, and entropy for DBT were also calculated at various temperatures. Moreover, calculations of the NLO were carried out to obtain the title compound’s electric dipole moment and polarizability properties. To illustrate the effect of the theoretical method on the spectroscopic and structural properties of DBT, experimental data of structural and spectroscopic parameters were used. The correlational analysis results were observed to indicate a strong relationship between the experimental and theoretical results.
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Wang CH, Liu ZY, Huang CH, Chen CT, Meng FY, Liao YC, Liu YH, Chang CC, Li EY, Chou PT. Chapter Open for the Excited-State Intramolecular Thiol Proton Transfer in the Room-Temperature Solution. J Am Chem Soc 2021; 143:12715-12724. [PMID: 34355563 DOI: 10.1021/jacs.1c05602] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We report here, for the first time, the experimental observation on the excited-state intramolecular proton transfer (ESIPT) reaction of the thiol proton in room-temperature solution. This phenomenon is demonstrated by a derivative of 3-thiolflavone (3TF), namely, 2-(4-(diethylamino)phenyl)-3-mercapto-4H-chromen-4-one (3NTF), which possesses an -S-H···O═ intramolecular H-bond (denoted by the dashed line) and has an S1 absorption at 383 nm. Upon photoexcitation, 3NTF exhibits a distinctly red emission maximized at 710 nm in cyclohexane with an anomalously large Stokes shift of 12 230 cm-1. Upon methylation on the thiol group, 3MeNTF, lacking the thiol proton, exhibits a normal Stokes-shifted emission at 472 nm. These, in combination with the computational approaches, lead to the conclusion of thiol-type ESIPT unambiguously. Further time-resolved study renders an unresolvable (<180 fs) ESIPT rate for 3NTF, followed by a tautomer emission lifetime of 120 ps. In sharp contrast to 3NTF, both 3TF and 3-mercapto-2-(4-(trifluoromethyl)phenyl)-4H-chromen-4-one (3FTF) are non-emissive. Detailed computational approaches indicate that all studied thiols undergo thermally favorable ESIPT. However, once forming the proton-transferred tautomer, the lone-pair electrons on the sulfur atom brings non-negligible nπ* contribution to the S1' state (prime indicates the proton-transferred tautomer), for which the relaxation is dominated by the non-radiative deactivation. For 3NTF, the extension of π-electron delocalization by the diethylamino electron-donating group endows the S1' state primarily in the ππ* configuration, exhibiting the prominent tautomer emission. The results open a new chapter in the field of ESIPT, covering the non-canonical sulfur intramolecular H-bond and its associated ESIPT at ambient temperature.
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Affiliation(s)
- Chun-Hsiang Wang
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan (R.O.C.)
| | - Zong-Ying Liu
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan (R.O.C.)
| | - Chun-Hao Huang
- Department of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan (R.O.C.)
| | - Chao-Tsen Chen
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan (R.O.C.)
| | - Fan-Yi Meng
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan (R.O.C.)
| | - Yu-Chan Liao
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan (R.O.C.)
| | - Yi-Hung Liu
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan (R.O.C.)
| | - Chao-Che Chang
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan (R.O.C.)
| | - Elise Y Li
- Department of Chemistry, National Taiwan Normal University, Taipei 11677, Taiwan (R.O.C.)
| | - Pi-Tai Chou
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan (R.O.C.)
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Karaboduk K. Modification of screen-printed gold electrode with 1,4-dithiothreitol: application to sensitive voltammetric determination of Sudan II. FOOD QUALITY AND SAFETY 2021. [DOI: 10.1093/fqsafe/fyaa039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Abstract
Objectives
The aim of this study is to investigate the electrochemical behavior of Sudan II (SuII) using a screen-printed gold electrode (SPGE) modified with 1,4-dithiothreitol (DTT) and to determine the amount of Sudan II by voltammetry.
Materials and Methods
A DTT-modified screen-printed gold electrode (DTT/SPGE) was fabricated and its application for differential pulse voltammetric (DPV) determination of SuII was reported. Fourier transform infrared spectroscopy (FT-IR), cyclic voltammetry and electrochemical impedance spectroscopy were used for the characterization of the modified electrode. The effects of instrumental and chemical parameters were optimized for the determination of SuII. The fabricated electrode was used for the analysis of SuII in fortified and real samples. High-performance liquid chromatography was preferred as a reference method for the evaluation of the obtained voltammetric results.
Results
The electrochemical studies and FT-IR demonstrated that the SPGE was modified with DTT. The obtained peak current at DTT/SPGE was 6.67 times higher than that recorded with SPGE. At the optimized conditions of DPV in pH = 2.5 of H2SO4, the oxidation peak current of SuII was proportional to its concentration in range: 0.001–1.500 μmol l–1 with a detection limit of 0.0002 μmol l–1 (S/N = 3). For the analysis of SuII, 101.67%–104.33% of recovery percentage was obtained.
Conclusions
A new electrode was successfully improved for the determination of SuII. This highly selective and sensitive electrode supplied the fast determination of SuII in ketchup, chili sauce and salsa dip sauce. In addition, voltammetric and chromatographic results are found to be consistent.
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Affiliation(s)
- Kuddusi Karaboduk
- Life Sciences Application and Research Center, Gazi University, Golbasi, Ankara, Turkey
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Sorrentino JP, Orsi DL, Altman RA. Acid-Catalyzed Hydrothiolation of gem-Difluorostyrenes to Access α,α-Difluoroalkylthioethers. J Org Chem 2021; 86:2297-2311. [PMID: 33471529 PMCID: PMC7869866 DOI: 10.1021/acs.joc.0c02440] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The substitution of hydrogen atoms with fluorine in bioactive molecules can greatly impact physicochemical, pharmacokinetic, and pharmacodynamic properties. However, current synthetic methods cannot readily access many fluorinated motifs, which impedes utilization of these groups. Thus, the development of new methods to introduce fluorinated functional groups is critical for developing the next generation of biological probes and therapeutic agents. The synthesis of one such substructure, the α,α-difluoroalkylthioether, typically requires specialized conditions that necessitate early-stage installation. A late-stage and convergent approach to access α,α-difluoroalkylthioethers could involve nucleophilic addition of thiols across gem-difluorostyrenes. Unfortunately, under basic conditions, nucleophilic addition to gem-difluorostyrenes generates an anionic intermediate that can undergo facile elimination of fluoride to generate α-fluorovinylthioethers. To overcome this decomposition, we herein exploit an acid-based catalyst system to facilitate simultaneous nucleophilic addition and protonation of the unstable intermediate. Ultimately, the optimized mild conditions afford the desired α,α-difluoroalkylthioethers in high selectivity and moderate to excellent yields. These α,α-difluoroalkylthioethers are less nucleophilic and more oxidatively stable relative to nonfluorinated thioethers, suggesting the potential application of this unexplored functional group in biological probes and therapeutic agents.
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Affiliation(s)
- Jacob P. Sorrentino
- Department of Medicinal Chemistry, The University of Kansas, Lawrence, Kansas 66045, United States
| | - Douglas L. Orsi
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts 02142, United States
| | - Ryan A. Altman
- Department of Medicinal Chemistry and Molecular Pharmacology and Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, United States
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Synthesis of thiolated polysaccharides for formation of polyelectrolyte multilayers with improved cellular adhesion. Carbohydr Polym 2016; 157:1205-1214. [PMID: 27987824 DOI: 10.1016/j.carbpol.2016.10.088] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 10/21/2016] [Accepted: 10/29/2016] [Indexed: 12/27/2022]
Abstract
Intrinsic cross-linking is not only useful for increasing stability, but also for tailoring mechanical properties of polyelectrolyte multilayers (PEM) on implants and tissue engineering scaffolds. Here, a novel route for synthesizing thiolated chitosan (t-Chi) based on the application of 3,3'-dithiodipropionic acid was applied, while thiolated chondroitin sulfate (t-CS) was conjugated by 3,3'-dithiobis (propanoic hydrazide). Both products were subsequently reduced to obtain the free thiols. The thiol content, structural changes and degree of substitution were studied by UV-vis, FTIR, Raman and 1H NMR spectroscopy, respectively. Chi and CS can be used for PEM formation with the layer-by-layer method, due to the cationic nature of Chi at pH values below 5.0 and the anionic character of CS. Comparative studies on the formation of native Chi/CS versus t-Chi/t-CS PEM with surface plasmon resonance and ellipsometry revealed higher layer mass. We also found that the PEM composed of t-Chi/t-CS had superior cell adhesion properties for human keratinocytes in comparison to the native PEM.
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Bandyopadhyay S, Chattopadhyay S, Dey A. The protonation state of thiols in self-assembled monolayers on roughened Ag/Au surfaces and nanoparticles. Phys Chem Chem Phys 2016; 17:24866-73. [PMID: 26343998 DOI: 10.1039/c5cp04450b] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The protonation state of thiols in self-assembled monolayers (SAMs) on Ag and Au surfaces and nanoparticles (NPs) has been an issue of contestation. It has been recently demonstrated that deuterating the thiol proton produces ostentatious changes in the Raman spectra of thiols and can be used to detect the presence of the thiol functional group. Surface enhanced Raman spectroscopy (SERS) of H/D substituted aliphatic thiols on Ag surfaces clearly shows the presence of S-H vibration between 2150-2200 cm(-1) which shifts by 400 cm(-1) upon deuteration and a simultaneous >20 cm(-1) shift in the C-S vibration of thiol deuteration. Large shifts (>15 cm(-1)) in the C-S vibration are also observed for alkyl thiol SAMs on Au surfaces. Alternatively, neither the S-H vibration nor the H/D isotope effect on the C-S vibration is observed for alkyl thiol SAMs on Ag/Au NPs. XPS data on Ag/Au surfaces bearing aliphatic thiol SAMs show the presence of both protonated and deprotonated thiols while on Ag/Au NPs only deprotonated thiols are detected. These data suggest that aliphatic thiol SAMs on Au/Ag surfaces are partially protonated whereas they are totally deprotonated on Au/Ag NPs. Aromatic PhSH SAMs on Ag/Au surfaces and Ag/Au NPs do not show these vibrations or H/D shifts as well indicating that the thiols are deprotonated at these interfaces.
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Affiliation(s)
- Sabyasachi Bandyopadhyay
- Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Kolkata, West Bengal 70003, India.
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Gökce H, Öztürk N, Ceylan Ü, Alpaslan YB, Alpaslan G. Thiol-thione tautomeric analysis, spectroscopic (FT-IR, Laser-Raman, NMR and UV-vis) properties and DFT computations of 5-(3-pyridyl)-4H-1,2,4-triazole-3-thiol molecule. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2016; 163:170-180. [PMID: 27054702 DOI: 10.1016/j.saa.2016.03.041] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 03/21/2016] [Accepted: 03/27/2016] [Indexed: 06/05/2023]
Abstract
In this study, the 5-(3-pyridyl)-4H-1,2,4-triazole-3-thiol molecule (C7H6N4S) molecule has been characterized by using FT-IR, Laser-Raman, NMR and UV-vis spectroscopies. Quantum chemical calculations have been performed to investigate the molecular structure (thione-thiol tautomerism), vibrational wavenumbers, electronic transition absorption wavelengths in DMSO solvent and vacuum, proton and carbon-13 NMR chemical shifts and HOMOs-LUMOs energies at DFT/B3LYP/6-311++G(d,p) level for all five tautomers of the title molecule. The obtained results show that the calculated vibrational wavenumbers, NMR chemical shifts and UV-vis wavelengths are in a good agreement with experimental data.
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Affiliation(s)
- Halil Gökce
- Vocational High School of Health Services, Giresun University, 28100 Giresun, Turkey.
| | - Nuri Öztürk
- Dereli Vocational High School, Giresun University, 28950 Giresun, Turkey
| | - Ümit Ceylan
- Vocational High School of Health Services, Giresun University, 28100 Giresun, Turkey
| | - Yelda Bingöl Alpaslan
- Department of Biophysics, Faculty of Medicine, Giresun University, 28100 Giresun, Turkey
| | - Gökhan Alpaslan
- Vocational High School of Health Services, Giresun University, 28100 Giresun, Turkey
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Roy S, Baral A, Bhattacharjee R, Jana B, Datta A, Ghosh S, Banerjee A. Preparation of multi-coloured different sized fluorescent gold clusters from blue to NIR, structural analysis of the blue emitting Au7 cluster, and cell-imaging by the NIR gold cluster. NANOSCALE 2015; 7:1912-1920. [PMID: 25529745 DOI: 10.1039/c4nr04338c] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Blue, green, orange-red, red and NIR emitting gold quantum clusters have been prepared in aqueous media by using a bioactive peptide glutathione (reduced) at physiological pH. Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) analyses show that the core structure sizes of the five different gold clusters are Au7 (blue), Au16 (green), Au19 (orange-red), Au21 (red) and Au22 (NIR). The photo-stability and pH-stability of these quantum clusters have been measured, and these are photo-stable against continuous UV irradiation for a few hours. They also exhibit moderate to good pH-stability within the pH range of 5-12.5. A computational study reveals the organisation of gold atoms in the thiolate-protected blue quantum cluster and its several structural parameters, including the mode of interaction of ligand molecules with Au atoms in the Au7 cluster. Interestingly, it has been found that NIR emitting gold quantum cluster can easily be internalized into the adenocarcinomic human alveolar basal epithelial cell line (A549 cell line). Moreover, a MTT assay indicates that our NIR emitting gold quantum cluster show very low cytotoxicy to A549 cancer cells.
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Affiliation(s)
- Subhasish Roy
- Department of Biological Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032, India.
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