556 results on '"ALKANETHIOLS"'
Search Results
2. Palladium-Catalyzed Carbothiolation by Using Thioesters with Formation of a Quaternary Carbon.
- Author
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Okura, Yoshifumi, Ito, Ryunosuke, Kumazawa, Hyu, and Nakada, Masahisa
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THIOESTERS , *CHROMANS , *ALKANETHIOLS , *BIOCHEMICAL substrates , *CARBON , *PALLADIUM catalysts - Abstract
A Pd-catalyzed carbothiolation using thioesters, with the formation of a quaternary carbon, is described. Carbothiolation using thioesters was problematic due to a direct-coupling side reaction that produced a sulfide, but this side reaction was successfully suppressed by an appropriate selection of the thioester and the reaction conditions. In the preparation of chroman or coumaran derivatives by this method, the reaction using S -phenyl 4-methoxybenzenecarbothioate Pd(PPh3)4 , and Cs2 CO3 at 100 °C in toluene afforded the desired products in good yields (77–92%). The carbothiolation reaction also proceeded with esters of alkanethiols in higher yields (56–93%) than those obtained from the previously reported carbothiolation using triisopropylsilyl (TIPS) thioethers (12–63%). The developed Pd-catalyzed carbothiolation is applicable in the preparation of a wide range of products, including a tetralin derivative and an indoline derivative. The Pd-catalyzed carbothiolation using thioesters was found to be comparable with a previously reported carbothiolation using TIPS thioethers in terms of the yield and substrate scope, and to be a superior alternative owing to the stability and lower cost of thioesters. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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3. Controlled Release of Volatile Enones from Monomeric and Dimeric Thioether, Sulfoxide and Sulfone Profragrances.
- Author
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Trachsel, Alain, Leocata, Sabine, de Saint Laumer, Jean‐Yves, and Herrmann, Andreas
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SULFUR compounds , *KETONES , *ALKANETHIOLS , *SULFIDES , *SULFOXIDES , *VOLATILE organic compounds , *PERFUMES , *CARBONYL compounds - Abstract
Thioether (sulfide) profragrances are readily prepared by 1,4‐addition of alkanethiols to enones (thia‐Michael reaction). Under ambient conditions, they slowly release the parent enones, thus generating a long‐lasting perfumery effect. The fragrance release of profragrances obtained by 1,4‐addition of S, O and N nucleophiles to enones was compared on cotton and on a hard surface for monomeric and dimeric structures. To avoid the uncontrolled generation of volatile sulfur compounds from thioethers, we investigated the extent to which different side reactions occurred next to the expected formation of enones and alkanethiols. Headspace analyses on cotton showed that enones and aldehydes were the major reaction products, whereas none or only traces of β‐mercaptoketones, diketones or alkanethiols were detected. The absence of alkanethiols indicated that 1,4‐elimination of thioethers was not a major pathway for fragrance release. Extraction of the cotton sheets after analysis showed that thioethers were oxidised to sulfoxides, which then can generate enones by 1,4‐elimination. Thioethers, sulfoxides and sulfones were shown to efficiently release enones in practical applications. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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4. Biochemistry of Targets and Probes
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Carrara, Sandro and Carrara, Sandro
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- 2024
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5. Effect of Solution Composition on the Desorption Behavior of Self-Assembled Monolayers of Alkanethiols with Different Terminal Groups.
- Author
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Ovchinnikova, S. N. and Aleksandrova, T. P.
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ALKANETHIOLS , *MONOMOLECULAR films , *DESORPTION , *AMINO group , *SULFHYDRYL group , *ALKALINE solutions , *CHRONOAMPEROMETRY - Abstract
Voltammetry and chronoamperometry are used to study the effect of the solution composition on the desorption behavior of self-assembled monolayers of alkanethiols with approximately the same chain length but different terminal groups of thiols (R: –CH3, –CH2OH, and –NH2). The hydrophilic properties of the terminal groups for the studied thiols increased in the –CH3 –NH2 ≤ –CH2OH series. It is found that the anionic and cationic composition of electrolyte affected significantly the electrochemical stability and blocking ability of self-assembled monolayers of thiols with different terminal groups. It is established that the electrochemical stability and blocking ability of the self-assembled monolayers decreased in the Li+, Na+, K+ series in alkaline solutions regardless of the thiol terminal group. The cation nature in perchlorate and chloride solutions manifested itself only for thiol with the –NH2 terminal group. The shape of cathodic voltammograms changed for this thiol when passing from alkaline to and Сl– medium, possibly owing to a change in the amino group protonation degree. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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6. A synthesis of triacetyl-substituted 1,2,3,4-tetrahydropyridine by the reaction of 3-[(alkylsulfanyl)methyl]pentane-2,4-diones with aniline.
- Author
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Baeva, Larisa A., Gataullin, Rail R., and Nugumanov, Radik M.
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ANILINE , *ALKANETHIOLS , *RING formation (Chemistry) - Abstract
The condensation of 3-[(alkylsulfanyl)methyl]pentane-2,4-diones with aniline in the presence of catalytic amounts of acetic acid led to the formation of 1,1',1''-(6-methyl-1-phenyl-1,2,3,4-tetrahydropyridine-3,3,5-triyl)triethanone. The reaction is presumably a tandem process, incorporating the formation of β-enaminone, elimination of the alkanethiol molecule from the β-enaminone and the starting pentane-2,4-dione, and a subsequent [4+2] cycloaddition of the resulting intermediates. The mechanism of the conversion may also involve intramolecular cyclization of the Michael addition products of 3-[(alkylsulfanyl)methyl]pentane-2,4-dione to 3-(imidoyl)but-3-en-2-one, formed from β-enaminones during the elimination of alkanethiols. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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7. Potassium salts catalyzed oxidative coupling of alkanethiols with sulfur: the effect of solid-liquid phase transfer of crown ether.
- Author
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Xu, Zhaoyang, Zhang, Zihan, Wang, Rui, Li, Fei, and Jiang, Heng
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OXIDATIVE coupling , *POTASSIUM salts , *ALKANETHIOLS , *SULFUR , *CROWN ethers , *ATMOSPHERIC pressure , *WEATHER - Abstract
Potassium salts (KA, A = anion) that catalyzed the oxidative coupling of alkanethiols (RSH) to dialkyl disulfide (R2S2) were investigated by using sulfur as oxidant and 18-crown-6 ether as phase transfer agent under solvent-free conditions at atmospheric pressure. Crown ether (15-crown-5 ether, 18-crown-6 ether, dibenzo-18-crown-6 ether) showed excellent solid-liquid phase transfer effect in solid KA catalyzed reaction. RS− is the key active species of the KA catalyzed reaction. The catalytic activity of KA is affected by the pKa of conjugated acid (HA) of anion A− in KA. The larger the pKa of the corresponding HA, the more active for KA to activate RSH to generate RS−. Among the KA investigated, the yield of (n-C8H17)2S2 for the K2CO3, K3PO4·3H2O and K2SnO3·3H2O catalyzed reaction reached more than 98.0%. The yield of R2S2 can reach more than 95.0% by 0.1 mol% 18-C-6 (based on sulfur) and 0.1 mol% K2CO3 (based on sulfur) catalyzed the oxidative coupling of different alkanethiols. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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8. Self-Assembly of Alkanethiols on an Oxide-Free Surface of a Copper Electrode from Alkaline Solutions under Electrochemical Control.
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Ovchinnikova, S. N. and Alexandrova, T. P.
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COPPER surfaces , *COPPER electrodes , *ALKANETHIOLS , *ALKALINE solutions , *COPPER , *ETHANOL - Abstract
Using voltammetry and chronoamperometry, the formation process and properties of insulating nanofilms of alkanethiols with different chain lengths (butane-, octane-, dodecanethiol) obtained on an oxide-free copper surface were studied. The electrochemical method for modifying the copper surface includes the removal of the oxide layer by its cathodic reduction, the adsorption of a thiol under electrochemical control, followed by studying the properties of the resulting nanofilm by voltammetry in one solution. It is shown that, with this approach, a dense thiol film is formed, with its blocking properties depending on the adsorption potential, the time of contact of the electrode with the thiol-containing solution, the thiol concentration, and the presence of dissolved oxygen in the solution. The introduction of ethanol into an aqueous alkali solution leads to a significant acceleration of the process of self-assembly of dodecanethiol, but greatly inhibits the process of self-assembly of butanethiol. The approach proposed in this work makes it possible to use aerated low-concentration thiol-containing solutions to obtain alkanethiol films on the Cu surface with good blocking properties. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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9. The plasmonic behaviours of gold nanoparticles with different thiol (n = 6, 10, 12) capping agents.
- Author
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Amos, Olusegun, Mehl, Georg. H., and Pashameah, Rami Adel
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PLASMONICS ,GOLD nanoparticles ,SULFHYDRYL group ,WAVELENGTH assignment ,ULTRAVIOLET radiation - Abstract
The intense absorbance and scattering of incident light at the surface plasmon resonance wavelength of gold nanoparticles (AuNPs) is of paramount importance in its various and diverse applications. Being governed by their morphologies and surface chemistry, the optical property of AuNPs can be tuned to suit variety of applications by careful and systematic engineering of the particle surface. Among other variables, the nature of the ligands or capping agents employed and their concentrations play vital roles. Three different alkanethiols, namely 1-dodecanethiol (DDT), 1-decanethiol (DT) and 1-hexanethiol (HT) were investigated as capping agents in different concentration of gold/thiol ([Au]/[Thiol]) ratios of 7:1, 5:1, 3:1, 1:1, 1:3 and 1:5. First, the AuNPs with average particle sizes of 2 nm and characterised by
1 H NMR, UV–visible, and TEM. The1 H NMR confirmed the capping of gold nanoparticles by the thiol. The TEM image confirmed the monodispersity of the nanoparticles with average size distributions of 2.4 nm, and plasmon absorption wavelength peaks at 505 nm was confirmed by the UV. There were variations in the values of the plasmonic peaks with the nature and concentrations of the capping agents. [ABSTRACT FROM AUTHOR]- Published
- 2023
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10. Organic superbase-catalyzed oxidation of alkanethiols to dialkyl disulfides by elemental sulfur.
- Author
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Zhang, Zihan, Xu, Zhaoyang, Wang, Rui, Li, Fei, and Jiang, Heng
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ALKANETHIOLS , *SULFUR , *ORGANIC bases , *OXIDATION , *ATMOSPHERIC pressure , *DISULFIDES - Abstract
Under atmospheric pressure and solvent-free conditions, organic superbase (SB) catalyzed the oxidation of alkanethiols (RSH) to dialkyl disulfides (R2S2) by using sulfur as oxidant was investigated. The results showed that amidines (DBU, DBN) and guanidines (BTMG, MTBD, TMG) exhibited significantly higher catalytic activity than common organic bases. Under the condition of 3.0 molar ratio of RSH/S (50 mol% excess of RSH), 99–100% yield of (n-C8H17)2S2 could be obtained with 0.1 mol% SB and more than 95% yield of (n-C8H17)2S2 could be also obtained even if with 0.001 mol% SB. The yield of target product R2S2 (R = alkyl, phenyl) was still obtained above 90% when the molar ratio of RSH/S was 2.1 (5 mol% excess of RSH). R2S3 was the only by-product, and no R2S4 was generated. The deprotonation ability of SB to RSH is significantly higher than that of common organic bases, and RS− is the key active species in the catalytic reaction. This synthetic method has the advantages of operational simplicity, inexpensive, and the applicability to 20–30 g scale synthesis strengthen its potential applications for preparing disulfide at an industrial scale. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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11. A Simple and Modular Access to 4-Mercapto-4-methylpentanoic Acid: A Useful Building Block in Antibody-Drug Conjugates Research.
- Author
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Salamone, Logan, Lepeintre, Martin, Revil-Baudard, Vincent L., Serpier, Fabien, and Petit, Laurent
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ANTIBODY-drug conjugates , *INTERMEDIATES (Chemistry) , *CARBOXYLIC acids , *SODIUM compounds , *ESTERS , *ALKANETHIOLS - Abstract
Keywords: ADC; xanthate chemistry; gaseous olefins; amide coupling; linker; Maytansinoids; mercapto acid EN ADC xanthate chemistry gaseous olefins amide coupling linker Maytansinoids mercapto acid 2177 2185 9 07/03/23 20230718 NES 230718 Antibody-Drug Conjugates (ADC) belong to a novel class of anti-cancer drugs whose principle is based on targeted therapy approaches. ADC, xanthate chemistry, gaseous olefins, amide coupling, Maytansinoids, mercapto acid, linker Finally, a masked I N i -methylamino acid was coupled successfully to the acid, highlighting the feasibility of our method in ADC chemistry. Amide Coupling; General Procedure 4-((Ethoxycarbonothioyl)thio)-4-methylpentanoic acid ( B 23 b ; 0.75 g, 3.2 mmol, 1.0 equiv.) was dissolved in EtOAc (20 mL) and the resulting solution was cooled to 0-5 °C. [Extracted from the article]
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- 2023
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12. Theoretical Study of Au-S Interaction in Clusters Models of a α-cyclodextrin Complex.
- Author
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ORELLANA, CARLOS and MENDIZABAL, FERNANDO
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GOLD clusters ,SULFHYDRYL group ,INTERMOLECULAR interactions ,THIOLS ,ALKANETHIOLS ,DISPERSION (Chemistry) ,CAPTOPRIL ,MOLECULES - Abstract
Theoretical calculations were correlated to elucidate the interface interaction between thiol groups of host-guest systems and gold cluster. The 1-octanethiol molecule acts as guest into a-cyclodextrin host to form a supramolecular complex in which is stabilizing gold clusters. The intermolecular interaction and the vibrational frequencies nature between a host-guest system and gold cluster were elucidated by a theoretical point of view at the MP2, SCS-MP2, and PBE-D3 methods. It is showing a van der Waals interaction and a good vibrational frequencies correlation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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13. Tunable CO2 electroreduction to ethanol and ethylene with controllable interfacial wettability.
- Author
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Lin, Yan, Wang, Tuo, Zhang, Lili, Zhang, Gong, Li, Lulu, Chang, Qingfeng, Pang, Zifan, Gao, Hui, Huang, Kai, Zhang, Peng, Zhao, Zhi-Jian, Pei, Chunlei, and Gong, Jinlong
- Subjects
ELECTROLYTIC reduction ,ETHYLENE ,WETTING ,ETHANOL ,ALKANETHIOLS - Abstract
The mechanism of how interfacial wettability impacts the CO
2 electroreduction pathways to ethylene and ethanol remains unclear. This paper describes the design and realization of controllable equilibrium of kinetic-controlled *CO and *H via modifying alkanethiols with different alkyl chain lengths to reveal its contribution to ethylene and ethanol pathways. Characterization and simulation reveal that the mass transport of CO2 and H2 O is related with interfacial wettability, which may result in the variation of kinetic-controlled *CO and *H ratio, which affects ethylene and ethanol pathways. Through modulating the hydrophilic interface to superhydrophobic interface, the reaction limitation shifts from insufficient supply of kinetic-controlled *CO to that of *H. The ethanol to ethylene ratio can be continuously tailored in a wide range from 0.9 to 1.92, with remarkable Faradaic efficiencies toward ethanol and multi-carbon (C2+ ) products up to 53.7% and 86.1%, respectively. A C2+ Faradaic efficiency of 80.3% can be achieved with a high C2+ partial current density of 321 mA cm−2 , which is among the highest selectivity at such current densities. The mechanism of how interfacial wettability impacts the CO2 electcgq Herein, the authors describe the design and realization of controllable equilibrium of kinetic controlled *CO and *H to reveal its contribution to ethylene and ethanol pathways. [ABSTRACT FROM AUTHOR]- Published
- 2023
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14. Formation and Thermal Stability of Ordered Self-Assembled Monolayers by the Adsorption of Amide-Containing Alkanethiols on Au(111).
- Author
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Son, Young Ji, Han, Jin Wook, Kang, Hungu, Seong, Sicheon, Han, Seulki, Maeda, Shoichi, Chikami, Shunta, Hayashi, Tomohiro, Hara, Masahiko, and Noh, Jaegeun
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THERMAL stability , *SCANNING tunneling microscopy , *ALKANETHIOLS , *X-ray photoelectron spectroscopy , *REARRANGEMENTS (Chemistry) , *MONOMOLECULAR films - Abstract
We examined the surface structure, binding conditions, electrochemical behavior, and thermal stability of self-assembled monolayers (SAMs) on Au(111) formed by N-(2-mercaptoethyl)heptanamide (MEHA) containing an amide group in an inner alkyl chain using scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) to understand the effects of an internal amide group as a function of deposition time. The STM study clearly showed that the structural transitions of MEHA SAMs on Au(111) occurred from the liquid phase to the formation of a closely packed and well-ordered β-phase via a loosely packed α-phase as an intermediate phase, depending on the deposition time. XPS measurements showed that the relative peak intensities of chemisorbed sulfur against Au 4f for MEHA SAMs formed after deposition for 1 min, 10 min, and 1 h were calculated to be 0.0022, 0.0068, and 0.0070, respectively. Based on the STM and XPS results, it is expected that the formation of a well-ordered β-phase is due to an increased adsorption of chemisorbed sulfur and the structural rearrangement of molecular backbones to maximize lateral interactions resulting from a longer deposition period of 1 h. CV measurements showed a significant difference in the electrochemical behavior of MEHA and decanethiol (DT) SAMs as a result of the presence of an internal amide group in the MEHA SAMs. Herein, we report the first high-resolution STM image of well-ordered MEHA SAMs on Au(111) with a (3 × 2√3) superlattice (β-phase). We also found that amide-containing MEHA SAMs were thermally much more stable than DT SAMs due to the formation of internal hydrogen networks in MEHA SAMs. Our molecular-scale STM results provide new insight into the growth process, surface structure, and thermal stability of amide-containing alkanethiols on Au(111). [ABSTRACT FROM AUTHOR]
- Published
- 2023
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15. Ground solid permanganate oxidative coupling of thiols into symmetrical/unsymmetrical disulfides: selective and improved process.
- Author
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Nguyen, Ngan-Giang Thi, Nguyen, Xuan-Triet, Nguyen, Ngoc-Huy, Luu, Thi Xuan Thi, and Dao, Xuan-Tien
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OXIDATIVE coupling , *DISULFIDES , *POTASSIUM permanganate , *INTERRACIAL couples , *THIOLS , *ALKANETHIOLS , *ALCOHOL , *FUNCTIONAL groups - Abstract
The oxidation of thiols to the symmetrical disulfides by using ground solid potassium permanganate under mild and solvent-free conditions has allowed us to selectively oxidize thiols in the presence of other readily oxidized functional groups such as alcohol, aldehyde, amine and alkene without the risk of producing undesired products via competitive oxidation reactions. Unsymmetrical disulfides have also been obtained in moderate to good yields from the oxidative coupling of mixed thiols. Furthermore, ultrasound or microwave irradiation is able to shorten the reaction time compared to conventional stirring in case of the oxidation of sterically demanding alkanethiols or arenethiols. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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16. Modification of 1-Hexene Vinylidene Dimer into Primary and Tertiary Alkanethiols.
- Author
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Kovyazin, Pavel V., Bikmeeva, Almira Kh., Palatov, Eldar R., and Parfenova, Lyudmila V.
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ALKANETHIOLS , *DISULFIDES , *THIOUREA , *SUBSTITUTION reactions , *SULFOXIDES , *THIOLS , *SUPPLY & demand - Abstract
Aliphatic thiols are in high demand in materials chemistry. Herein, a synthesis of thio-derivatives of 1-hexene vinylidene dimer is described. The approach, based on a hydroalumination reaction with further replacement of the organoaluminum function with sulfur using thiourea or dimethyl disulfide, provides anti-Markovnikov products, 2-butyloctane-1-thiol or 5-(methylsulfanylmethyl)undecane, in moderate yields. The reaction of a vinylidene dimer with phosphorus pentasulfide in the presence of catalytic amounts of (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) selectively gives the Markovnikov product, 5-methylundecane-5-thiol, with a yield of up to 77%. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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17. Model of self assembled monolayer based molecular diodes made of ferrocenyl-alkanethiols.
- Author
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Duche, David, Planchoke, Ujwol, Florian-Xuan Dang, Le Rouzo, Judikael, Bescond, Marc, Simon, Jean-Jacques, Balaban, Teodor Silviu, and Escoubas, Ludovic
- Subjects
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MONOMOLECULAR films , *ALKANETHIOLS , *DIODES , *QUANTUM tunneling , *RECTIFICATION (Electricity) - Abstract
There has been significant work investigating the use of self assembled monolayers (SAMs) made of ferrocenyl terminated alkanethiols for realizing molecular diodes, leading to remarkably large forward-to-reverse current rectification ratios. In this study, we use a multiband barrier tunneling model to examine the electrical properties of SAM-based molecular diodes made of HSC9Fc, HSC11Fc, and HSCiFcC13-i (0 ≤ I ≤ 13). Using our simple physical model, we reproduce the experimental data of charge transport across various ferrocenyl substituted alkanethiols performed by Nijhuis, Reus, and Whitesides [J. Am. Chem. Soc. 132, 18386184016 (2010)] and Yuan et al. [Nat. Commun. 6, 6324 (2015)]. Especially, the model allows predicting the rectification direction in HSCiFcC13-i (0 ≤I ≤13) based molecular diodes depending on the position of the ferrocenyl (Fc) moiety within the molecules. We show that the asymmetry of the barrier length at both sides of the Highest Occupied Molecular Orbital of the ferrocenyl moiety strongly contributes to the rectifying properties of ferrocenyl-alkanethiol based molecular junctions. Furthermore, our results reveal that bound and quasi-bound states play an important role in the charge transport. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
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18. Picosecond time resolved conductance measurements of redox molecular junctions.
- Author
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Arielly, Rani, Nachman, Nirit, Zelinskyy, Yaroslav, May, Volkhard, and Selzer, Yoram
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OXIDATION-reduction reaction , *ALKANETHIOLS , *HEAT conduction , *PICOSECOND pulses , *PHYSICAL constants - Abstract
Due to bandwidth limitations of state of the art electronics, the transient transport properties of molecular junctions are experimentally a terra incognita, which can only be explored if novel picosecond current-probing techniques are developed. Here we demonstrate one such approach: the laser pulsepair sequence scheme. The method is used to monitor in picosecond resolution the oxidation state of a redox molecule, 6-ferrocenyl-1-hexanethiol, within a junction and to quantify its redox rate constant, which is found to be (80 ps)-1. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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19. The sustainable microwave approach to H2S and RSH activation into Di- and Trisulfides in N-Methylpyrrolidone.
- Author
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Galustyan, A., Burmistrova, D.A., Fokin, V.A., Berberova, N.T., and Smolyaninov, I.V.
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ORGANOSULFUR compounds , *MICROWAVES , *HYDROGEN sulfide , *HYDROCARBONS , *POLYSULFIDES , *ALKANETHIOLS - Abstract
• Sustainable microwave method for H 2 S and RSH transformation to value-added products. • N-methylpyrrolidone is used as a reaction medium for the synthesis of polysulfides. • The process enables the synthesis of organosulfur compounds from technogenic waste. A reagent- and waste-free method for the transformation of hydrogen sulfide and thiols with С 3 -С 8 hydrocarbons groups into value-added di- and trisulfides is proposed under the microwave irradiation. The hydrogen sulfide solution in N-methylpyrrolidone was used as the reaction medium to occur the interaction with different thiols. The influence of the microwave irradiation power, duration, the temperature and thiol structure on the yield and ratio of target products has been investigated. It is found that the effective microwave power for activation of H 2 S and RSH should be at least 200 W, while increasing the reaction temperature reduces the contact time. The maximum values for the yield of di- and trisulfides were obtained at 280 W and 100 °C. High selectivity of trisulfide formation was observed in the case of alkanethiols C 3 -C 5 , especially for compounds with isomeric hydrocarbons groups. Differences in the mechanisms of H 2 S interaction with linear and branched thiols based on the formation of alkylhydropolysulfide intermediates have been identified. The proposed scheme of utilization of H 2 S and low-molecular-weight thiols into organic polysulfides under microwave irradiation was suggested. [Display omitted] [ABSTRACT FROM AUTHOR]
- Published
- 2024
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20. Reactions of (1-Bromoethenyl)(diphenyl)phosphine Oxide with NH-, OH-, and SH-Nucleophiles.
- Author
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Ovakimyan, M. Zh., Gasparyan, G. Ts., Poghosyan, A. S., Bichakhchyan, A. S., Derdzyan, L. V., Stepanyan, H. M., and Muradyan, R. E.
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PHOSPHINE oxides , *DIPHENYL , *ANTIBACTERIAL agents , *ALKANETHIOLS , *PYRAZOLES , *TRIAZOLES - Abstract
The reactions of (1-bromoethenyl)(diphenyl)phosphine oxide with NH-, OH-, SH-nucleophiles were studied. The reaction of phosphine oxide with alcohols and alkanethiols led to the formation of the corresponding adducts, while in reactions with pyrazole, imidazole and triazole (E)-(vinyl)(diphenyl)phosphine oxide 2-(azol-1-yl)-derivatives were formed. Antibacterial and antitumor activity of (1-bromoethenyl)(diphenyl)phosphine oxide and its derivatives was studied. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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21. Localized surface plasmon resonance inflection points for improved detection of chemisorption of 1-alkanethiols under total internal reflection scattering microscopy.
- Author
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Ryu, Kyeong Rim, Kim, Geun Wan, and Ha, Ji Won
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SURFACE plasmon resonance , *GOLD nanoparticles , *ALKANETHIOLS , *WAVELENGTHS , *CHEMISORPTION - Abstract
Plasmonic gold nanoparticles are widely used in localized surface plasmon resonance (LSPR) sensing. When target molecules adsorb to the nanoparticles, they induce a shift in the LSPR scattering spectrum. In conventional LSPR sensing, this shift is monitored at the maximum of the LSPR scattering peak. Herein, we describe the sensitivity of detecting chemisorption of 1-alkanethiols with different chain lengths (1-butanethiol and 1-haxanethiol) on single gold nanorods (AuNRs) of fixed diameter (25 nm) and three different aspect ratios under a total internal reflection scattering microscope. For single AuNRs of all sizes, the inflection point (IF) at the long-wavelength side (or low-energy side) of the LSPR scattering peak showed higher detection sensitivity than the traditionally used peak maximum. The improved sensitivity can be ascribed to the shape change of the LSPR peak when the local refractive index is increased by chemisorption. Our results demonstrate the usefulness of tracking the curvature shapes by monitoring the homogeneous LSPR IF at the red side of the scattering spectrum of single AuNRs. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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22. Non-covalently embedded oxytocin in alkanethiol monolayer as Zn2+ selective biosensor.
- Author
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Attia, Jessica, Nir, Sivan, Mervinetsky, Evgeniy, Balogh, Dora, Gitlin-Domagalska, Agata, Alshanski, Israel, Reches, Meital, Hurevich, Mattan, and Yitzchaik, Shlomo
- Subjects
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OXYTOCIN , *ALKANETHIOLS , *ZINC ions , *BIOSENSORS , *PEPTIDES - Abstract
Peptides are commonly used as biosensors for analytes such as metal ions as they have natural binding preferences. In our previous peptide-based impedimetric metal ion biosensors, a monolayer of the peptide was anchored covalently to the electrode. Binding of metal ions resulted in a conformational change of the oxytocin peptide in the monolayer, which was measured using electrochemical impedance spectroscopy. Here, we demonstrate that sensing can be achieved also when the oxytocin is non-covalently integrated into an alkanethiol host monolayer. We show that ion-binding cause morphological changes to the dense host layer, which translates into enhanced impedimetric signals compared to direct covalent assembly strategies. This biosensor proved selective and sensitive for Zn2+ ions in the range of nano- to micro-molar concentrations. This strategy offers an approach to utilize peptide flexibility in monitoring their response to the environment while embedded in a hydrophobic monolayer. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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23. Microscopic mechanism of electron transfer through the hydrogen bonds between carboxylated alkanethiol molecules connected to gold electrodes.
- Author
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Yang Li, Xingchen Tu, Minglang Wang, Hao Wang, Sanvito, Stefano, and Shimin Hou
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ALKANETHIOLS , *HYDROGEN bonding , *CHARGE exchange , *CARBOXYLATION , *GOLD electrodes , *ATOMIC structure , *GREEN'S functions - Abstract
The atomic structure and the electron transfer properties of hydrogen bonds formed between two carboxylated alkanethiol molecules connected to gold electrodes are investigated by employing the non-equilibrium Green's function formalism combined with density functional theory. Three types of molecular junctions are constructed, in which one carboxyl alkanethiol molecule contains two methylene, -CH2, groups and the other one is composed of one, two, or three -CH2 groups. Our calculations show that, similarly to the cases of isolated carboxylic acid dimers, in these molecular junctions the two carboxyl, -COOH, groups form two H-bonds resulting in a cyclic structure. When self-interaction corrections are explicitly considered, the calculated transmission coefficients of these three H-bonded molecular junctions at the Fermi level are in good agreement with the experimen-tal values. The analysis of the projected density of states confirms that the covalent Au-S bonds localized at the molecule-electrode interfaces and the electronic coupling between -COOH and S dominate the low-bias junction conductance. Following the increase of the number of the -CH2 groups, the coupling between -COOH and S decreases deeply. As a result, the junction conductance decays rapidly as the length of the H-bonded molecules increases. These findings not only provide an explanation to the observed distance dependence of the electron transfer properties of H-bonds, but also help the design of molecular devices constructed through H-bonds. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
24. Random telegraph signals by alkanethiol-protected Au nanoparticles in chemically assembled single-electron transistors.
- Author
-
Kano, Shinya, Azuma, Yasuo, Tanaka, Daisuke, Sakamoto, Masanori, Teranishi, Toshiharu, Smith, Luke W., Smith, Charles G., and Majima, Yutaka
- Subjects
- *
NUCLEAR particle research , *NANOPARTICLES , *SEMICONDUCTORS , *HISTOGRAMS , *ALKANETHIOLS - Abstract
We have studied random telegraph signals (RTSs) in a chemically assembled single-electron transistor (SET) at temperatures as low as 300 mK. The RTSs in the chemically assembled SET were investigated by measuring the source-drain current, using a histogram of the RTS dwell time, and calculating the power spectrum density of the drain current-time characteristics. It was found that the dwell time of the RTS was dependent on the drain voltage of the SET, but was independent of the gate voltage. Considering the spatial structure of the chemically assembled SET, the origin of the RTS is attributed to the trapped charges on an alkanethiol-protected Au nanoparticle positioned near the SET. These results are important as they will help to realize stable chemically assembled SETs in practical applications. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
25. Atmospheric Oxygen Mediated Radical Hydrothiolation of Alkenes.
- Author
-
McCourt, Ruairí O. and Scanlan, Eoin M.
- Subjects
- *
ATMOSPHERIC oxygen , *ENE reactions , *FUNCTIONAL groups , *ALKANETHIOLS , *ALKENES , *REACTIVE oxygen species - Abstract
A mild, metal‐free, atmospheric oxygen‐mediated radical hydrothiolation of alkenes (and alkyne) is reported. A variety of sulfur containing motifs including alkanethiols, thiophenols and thioacids undergo an atmospheric oxygen‐mediated radical hydrothiolation reaction with a plethora of alkenes in good yield with excellent functional group compatibility, typically with short reaction times to furnish a range of functionalized products. Biomolecules proved tolerant to the conditions and the procedure is robust and easily executable requiring no specialized equipment. Concise mechanistic studies confirm the process proceeds through radical intermediates in a thiol‐ene reaction manifold. The methodology offers an efficient "green" approach for thiol‐ene mediated "click" ligation and a milder alternative to thermally initiated hydrothiolation processes. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
26. A Robust Methodology for the Synthesis of Phosphorothioates, Phosphinothioates and Phosphonothioates.
- Author
-
Jones, David J., O'Leary, Eileen M., and O'Sullivan, Timothy P.
- Subjects
- *
THIOPHOSPHATES , *ALKANETHIOLS , *MOLECULAR weights , *SULFUR , *HETEROCYCLIC compounds - Abstract
A robust methodology for the synthesis of phosphorothioates, phosphinothioates and phosphonothioates, including those bearing low molecular weight S‐alkyl side‐chains, is presented. Application of the "caesium effect" in conjunction with the disulfide 3,3'‐dithiobis(propionitrile), which acts as a shelf‐stable sulfur source, avoids recourse to malodorous alkanethiols and toxic P−Cl precursors. A diverse range of sulfur‐containing organophosphorus targets, including phosphorus‐based heterocycles, may be prepared in consistently high yields. This chemistry also provides ready access to the corresponding DBU salts which are potential substrates for Pd‐catalysed coupling reactions. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
27. Study of parameters affecting microcontact printing of thiols on gold-coated substrate.
- Author
-
Jaywant, Swapna A. and Arif, Khalid Mahmood
- Subjects
- *
MOLECULAR weights , *THIOLS , *ALKANETHIOLS , *POLYMERS , *PALLADIUM , *MICROMACHINING - Abstract
Microcontact printing (μ CP) is a type of soft-lithography technique, which is widely used for patterning self-assembled monolayers (SAMs). It is a convenient method to form SAMs of bio/chemical ink onto different surfaces such as polymers, palladium, silver and gold. A wide range of applications of this technology includes micromachining, patterning proteins, cells or DNA in biosensors. However, the application primarily depends on the type of the ink used. Here, we present an experimental study that provides information about the parameters that affect the μ CP process. Two different thiol inks (dithiothreitol (DTT) and glutathione (GSH)) have been used for obtaining SAMs on gold-coated substrates. Our findings suggest that transferring the alkanethiols over the gold surface is extremely dependent upon the molecular weight of thiol compound, concentration of the thiol solution and pH value of the buffer used. Furthermore, higher the molecular weight, concentration and pH value of the ink, lower is the time required for the process of μ CP. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
28. Interfacial electron transfer between Geobacter sulfurreducens and gold electrodes via carboxylate-alkanethiol linkers: Effects of the linker length.
- Author
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Füeg, M., Borjas, Z., Estevez-Canales, M., Esteve-Núñez, A., Pobelov, I.V., Broekmann, P., and Kuzume, A.
- Subjects
- *
GEOBACTER , *CHARGE exchange , *GOLD electrodes , *CARBOXYLATES , *ALKANETHIOLS - Abstract
Abstract Geobacter sulfurreducens (Gs) attachment and biofilm formation on self-assembled monolayers (SAMs) of carboxyl-terminated alkanethiol linkers with varied chain length on gold (Au) was investigated by electrochemical and microscopic methods to elucidate the effect of the surface modification on the current production efficiency of Gs cells and biofilms. At the initial stage of the cell attachment, the electrochemical activity of Gs cells at a submonolayer coverage on the SAM-Au surface was independent of the linker length. Subsequently, multiple potential cyclings indicated that longer linkers provided more biocompatible conditions for Gs cells than shorter ones. For Gs biofilms, on the other hand, the turnover current decreased exponentially with the linker length. During the biofilm formation, bacteria need to adjust from the initial planktonic state to an electrode-respiring state, which was triggered by a strong electrochemical stress found for shorter linkers, resulting in the formation of mature biofilms. Our results suggest that the initial cell attachment and the biofilm formation are two inherently different processes. Therefore, the effects of linker molecules, electron transfer efficiency and biocompatibility, must be explored simultaneously to understand both processes to increase the current production of electrogenic microorganisms in microbial fuel cells. Graphical abstract Unlabelled Image Highlights • Longer linkers provide more biocompatible condition for the attachment of Gs cells. • Gs biofilm growth is hindered by long linkers. • ET efficiency and biocompatibility are keys to improve the current production. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
29. Synthesis of Ethyl 2-[Alkyl(benzyl)sulfanylmethyl]-3-oxobutanoates and 3H-Pyrazol-3-ones Based Thereon.
- Author
-
Baeva, L. A., Nugumanov, R. M., Biktasheva, L. F., Nugumanov, T. R., and Fatykhov, A. A.
- Subjects
- *
FORMALDEHYDE , *ETHYL acetoacetate , *ALKANETHIOLS , *SODIUM hydroxide , *TAUTOMERISM , *HYDRAZINE - Abstract
Three-component condensation of ethyl acetoacetate with formaldehyde and alkanethiols in the presence of 0.1 equiv of sodium hydroxide afforded ethyl 2-[(alkylsulfanyl)methyl]-3-oxobutanoates, and analogous reaction with phenylmethanethiol led to the formation of ethyl 2-[(benzylsulfanyl)methyl]-2-(hydroxymethyl)-3-oxobutanoate. The condensation products reacted with hydrazine hydrate in ethanol at room temperature to give 4-{[alkyl(or benzyl)sulfanyl]methyl}-5-methyl-2,4-dihydro-3H-pyrazol-3-ones which were shown to exist in DMSO-d6 mainly as 1H-pyrazol-5(3)-ol tautomers. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
30. Tuning the interparticle distances in self-assembled gold nanoparticle films with their plasmonic responses.
- Author
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Kim, In-Hyun, Kim, Ji Hoon, Choi, Jeong-Yong, Shin, Chae Ho, Kim, Jung-Hwan, Bae, Gyun-Tack, and Shin, Kuan Soo
- Subjects
- *
MOLECULAR self-assembly , *GOLD nanoparticles , *DENSITY functional theory , *SERS spectroscopy , *STABILIZING agents , *ALKANETHIOLS - Abstract
Graphical abstract Highlight • Investigates the localized surface plasmon resonance (LSPR) properties of 2D film of Au nanoparticles on a glass substrate formed at the water-hexane interface. • 2D films of the Au nanoparticles with the ability to control the interparticle distances by the alkyl chain lengths of alkanethiol. • Density functional theory (DFT) calculation and finite-difference time domain (FDTD) simulation have been used to confirm the interparticle distances. • Au nanoparticles and also exhibit distinct interparticle-distance-dependent surface-enhanced Raman scattering (SERS) characteristics. Abstract This study presents the fabrication and characterization of imine-functionalized Au nanoparticle (Au NP) film using Poly (ethyleneimine) (PEI) as a reducing and surface stabilizing reagent. The PEI-capped Au NPs can be self-assembled at the water-hexane interface by adding alcohol containing alkanethiol. Furthermore, large-area film made from PEI and alkanethiol-capped Au NPs is produced on a glass substrate with varying interparticle distances that can be controlled by the alkyl chain lengths, ranging from C2 (ethanethiol), C4 (1-butnaethiol), C6 (1-hexanethiol), C8 (1-octanethiol), to C10 (1-decanethiol) at the water-hexane interface. These 2D films show strong collective localized surface plasmon resonance (LSPR) extinction bands that are tunable via near-field coupling of adjacent Au NPs. Pronounced chain-length-dependent red shifts of the SPR bands have been observed for the PEI-capped Au films. The obtained PEI-capped Au films exhibit distinct interparticle-distance-dependent SERS characteristics. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
31. Tailoring the Strength of Nanoporous Gold by Self-Assembled Monolayers of Alkanethiols.
- Author
-
Mameka, Nadiia, Lührs, Lukas, Heissler, Stefan, Gliemann, Hartmut, and Wöll, Christof
- Published
- 2018
- Full Text
- View/download PDF
32. Existence of a Precipitation Threshold in the Electrostatic Precipitation of Oppositely Charged Nanoparticles.
- Author
-
Nakanishi, Hideyuki, Deák, András, Hólló, Gábor, and Lagzi, István
- Subjects
- *
NANOPARTICLES , *ALKANETHIOLS , *GOLD nanoparticles , *NANOSTRUCTURED materials , *X-ray diffraction - Abstract
Oppositely charged nanoparticles precipitate rapidly only at the point of electroneutrality, wherein their charges are macroscopically compensated. We investigated the aggregation and precipitation of oppositely charged nanoparticles at concentrations ranging from 10 to 10−3 mm (based on gold atoms) by using UV/Vis measurements. We employed solutions of equally sized (4.6 nm) gold nanoparticles, which were functionalized and stabilized with either positively or with negatively charged alkanethiols. Results showed that oppositely charged nanoparticles do not precipitate if their concentration is below a certain threshold even if the electroneutrality condition is fulfilled. This finding suggests a universal behavior of chemical systems comprising oppositely charged building blocks such as ions and charged nanoparticles. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
33. Tetrahydrofuran Highly Enhances SAMDI Efficiency.
- Author
-
Yoo, Jin, Kang, Hyunook, Kim, Mi Kyoung, Chong, Youhoon, Bae, Se Won, and Yeo, Woon‐Seok
- Subjects
- *
TETRAHYDROFURAN , *BIOCONJUGATES , *IMMOBILIZED proteins , *SURFACE chemistry , *MATRIX-assisted laser desorption-ionization - Abstract
The control experiment using MeOH instead of THF showed no meaningful differences in SAMDI spectra as the fraction of MeOH increased, clearly implying that SAMDI efficiency was enhanced by THF (Supporting Information Figure S2). Keywords: Mass spectrometry; Self-assembled monolayer; SAMDI; Tetrahydrofuran; Alkanethiols EN Mass spectrometry Self-assembled monolayer SAMDI Tetrahydrofuran Alkanethiols 369 371 3 03/22/21 20210301 NES 210301 The use of tetrahydrofuran for a matrix-dissolving solvent highly improved the SAMDI MS efficiency for the analysis of SAMs on gold. We examined carboxylic acid-presenting SAMs and biomacromolecule-conjugated SAMs such as GST, -casein, and -casein and found that THF effectively enhanced the SAMDI signals. [Extracted from the article]
- Published
- 2021
- Full Text
- View/download PDF
34. Nanografting: A Method for Bottom-up Fabrication of Designed Nanostructures
- Author
-
Tian, Tian, LeJeune, Zorabel M., Serem, Wilson K., Yu, Jing-Jiang, Garno, Jayne C., and Tseng, Ampere A., editor
- Published
- 2011
- Full Text
- View/download PDF
35. Low detection limits using sandwich and inhibition assays on long-range surface plasmon waveguide biosensors.
- Author
-
Khodami, Maryam and Berini, Pierre
- Subjects
- *
POLARITONS , *WAVEGUIDES , *MICROFLUIDICS , *ALKANETHIOLS , *IMMUNOASSAY - Abstract
A long-range surface plasmon polariton waveguide composed of a gold stripe embedded in CYTOP with an etched microfluidic channel has been used as a label-free real-time biosensor to demonstrate enhanced assay formats capable of very low detection limits. Specifically, sandwich and inhibition (competitive) assays were developed and demonstrated using Bovine Serum Albumin (BSA) and anti-BSA produced in rabbit as a model bio-specific pair. Carbodiimide coupling to a self-assembled COOH-terminated alkanethiol monolayer on the gold stripe was used to immobilize biomaterial to its surface. The optical output power from the biosensor was measured continuously over time and converted into surface mass density. Titration curves were extracted for both immunoassays. We demonstrate that protein concentrations in solution of 10 pg/ml can be detected with a signal-to-noise ratio of 20 using this new optical biosensor technology. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
36. A perspective on the magnetism of alkanethiol-coated gold thin films.
- Author
-
Dong, Pengcheng and Trudel, Simon
- Subjects
- *
MAGNETISM , *ALKANETHIOLS , *MAGNETIC properties , *ANISOTROPY , *FERROMAGNETISM - Abstract
Intriguing ferromagnetic behaviour has been reported in gold thin films — a diamagnetic material in the bulk — wherein large magnetic moments and uncommon anisotropy are often hallmark features. The tuning of the electronic and magnetic properties by the presence of molecular self-assembled monolayers has been proposed. In this work, we present the study of the magnetism of a wide collection of alkanethiols of differing chain lengths coated on Au. We find no or only very weak magnetism, casting doubt on the universality and reproducibility of this phenomenon. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
37. Facile Preparation of Functional Group Gradient Surfaces by Desorption and Re‐Adsorption of Alkanethiols on Gold.
- Author
-
Kang, Hyunook, Jung, Woong, and Yeo, Woon‐Seok
- Subjects
- *
NANOPARTICLES , *MONOMOLECULAR films , *CHEMICAL reactions , *MASS spectrometry , *MATRIX-assisted laser desorption-ionization , *SURFACE chemistry - Published
- 2018
- Full Text
- View/download PDF
38. Regioselective Synthesis of 3-[2-(Alkylsulfanyl)ethyl]pyrazoles by Reaction of Alkanethiols with 3-Alkenylpyrazoles.
- Author
-
Kobelevskaya, V. A., Popov, A. V., Levkovskaya, G. G., Rudyakova, E. V., and Rozentsveig, I. B.
- Subjects
- *
ALKANETHIOLS , *REGIOSELECTIVITY (Chemistry) , *PYRAZOLE derivatives , *MARKOVNIKOV'S rule , *ALKENYL group - Abstract
3-Alkenyl-5-chloropyrazoles reacted with alkanethiols on heating to 60°C to afford in good yields 3-[2-(alkylsulfanyl)ethyl]-5-chloropyrazoles as a result of anti-Markovnikov addition to the alkenyl group. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
39. Mixed‐monolayer of N‐hydroxysuccinimide‐terminated cross‐linker and short alkanethiol to improve the efficiency of biomolecule binding for biosensing.
- Author
-
Ataman Sadık, Demet, Eksi‐Kocak, Haslet, Ertaş, Gülay, Boyacı, İsmail Hakkı, and Mutlu, Mehmet
- Subjects
- *
ALKANETHIOLS , *BIOMOLECULES , *BIOSENSORS , *STERIC hindrance , *SURFACE plasmon resonance , *SURFACE chemistry - Abstract
The goal of this study was to use a novel surface chemistry for modifying gold surfaces to decrease the steric hindrance, minimize the nonspecific bindings while providing directed immobilization of proteins for advancing the transducer property and to provide a biosensing platform for surface plasmon resonance (SPR) applications. Mixed self‐assembled monolayers (mSAMs) were prepared using 3,3′‐Dithiodipropionic acid di (N‐hydroxysuccinimide ester) (DSP) and 6‐mercapto‐1‐hexanol (MCH) and the selected model proteins bovine serum albumin (BSA) and lysozyme were tested for binding efficiency. First, binding of these two proteins at constant concentration to different DSP:MCH mSAMs were compared to deduce the best molar ratio for forming mSAM using a continuous flow system coupled to SPR. Coincidently the maximum protein binding DSP:MCH mSAM were the same for both proteins. The change in Response Unit (∆RU) signal due to protein binding between DSP SAM and maximum protein binding DSP:MCH mSAM for lysozyme binding was more in comparison to BSA binding. Second, the effect of BSA and lysozyme concentration on binding efficiency to maximum protein binding DSP:MCH mSAM were compared and discussed. Lysozyme and BSA were shown to reach saturations on the same monolayer at concentrations of 5.7x10−5 and 8.96x10−6 [M] respectively, hence the molar ratio for limit concentrations is 6:1. The DSP SAM, MCH SAM, and DSP:MCH mSAMs where maximum and minimum protein binding occurs were also characterized with XPS and Attenuated total reflectance‐Fourier transform infrared (ATR‐FTIR) spectroscopy. Blank gold surface, maximum protein binding DSP:MCH mSAM and BSA immobilized DSP:MCH mSAM on gold surface were also investigated utilizing tapping mode AFM. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
40. Characterization of 11-mercaptoundecanoic and 3-mercaptopropionic acids adsorbed on silver by surface-enhanced Raman scattering.
- Author
-
Marques, Flávia C., Oliveira, Gabriela P., Teixeira, Raïssa A.R., Justo, Rodrigo M.S., Neves, Tatiana B.V., and Andrade, Gustavo F.S.
- Subjects
- *
ALKANETHIOLS , *SILVER nanoparticles , *SULFHYDRYL group , *CARBOXYLATES , *SOLVENTS - Abstract
Abstract Functionalized n -alkanethiols such as 11-mercaptoundecanoic (MUA) and 3-mercaptopropionic (MPA) acids are likely to adsorb in silver nanoparticles (AgNPs) solely through the thiol group (-SH) or also involving the carboxylate group (−COO−) in their structures. The relative tendency is closely related to pH conditions, solvent or the surface potential of the metallic nanoparticles. The SERS effect (Surface Enhancement Raman Scattering) was used for improving the understanding of MUA and MPA group interaction as well as the orientation of these organic compounds adsorbed on AgNPs and the influence of Cu(II) in solution. When analyzing the MPA SERS spectrum, it was verified that the thiol moiety was preferred to adsorb on the AgNPs surface in the thiolate form, presenting both anti and gauche conformations in both acidic and basic media. MUA SERS spectrum however, indicated that solely an anti conformation for the thiol moiety adsorbed on the AgNPs surface in both acidic and basic media. Adding Cu2+ ion resulted in coordination to the carboxyl or carboxylate moieties was confirmed by the downshift of the band assigned to OCO stretching. The presence of Cu(II) increased the tendency of gauche conformation for MPA; the coordination of MUA to Cu(II) resulted in a more upright conformation of the carboxylic/carboxylate moieties in both acidic and basic media, respectively. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
41. Catalytic Conversion of Petroleum Dialkyl Disulfides to Dialkyl Sulfides.
- Author
-
Mashkina, A. V. and Khairulina, L. N.
- Subjects
PETROLEUM chemicals ,ALKANETHIOLS ,METHANETHIOL ,ETHANETHIOL ,METHYL ethyl ketone - Abstract
A mixture of lower dialkyl disulfides (R = C
1 -C2 ) obtained by the demercaptanization of petrochemicals is converted to alkanethiols and dialkyl sulfides under the action of solid acid catalysts. In a helium medium, the main reaction products are methanethiol and ethanethiol; the total dialkyl sulfide selectivity is less than 20%. In a mixture of disulfides with methanol, the main reaction products are dimethyl, methyl ethyl, and diethyl sulfides; the total selectivity for these products achieves 98%. [ABSTRACT FROM AUTHOR]- Published
- 2018
- Full Text
- View/download PDF
42. Structures and properties of alkanethiol-modified graphene oxide/solution-polymerized styrene butadiene rubber composites: Click chemistry and molecular dynamics simulation.
- Author
-
Luo, Yanlong, Wu, Youping, Luo, Kaiqiang, Cai, Fei, Zhai, Tianshu, and Wu, Sizhu
- Subjects
- *
GRAPHENE oxide , *POLYBUTADIENE , *CLICK chemistry , *ALKANETHIOLS , *MOLECULAR structure , *POLYSTYRENE , *MOLECULAR dynamics , *SOLUTION (Chemistry) - Abstract
Alkanethiol-modified graphene oxides (GOs) containing alkanethiol (C x GO) molecules with varying chain lengths were synthesized through click chemistry. Then, C x GO/solution-polymerized styrene butadiene rubber (C x GO/SSBR) composites with different C x GO loadings were prepared by a solution-mixing method. By combining experiment and molecular dynamics (MD) simulation, we investigated the relationship between the microstructures and properties of the C x GO/SSBR composites. Results showed that the 1-heptanethiol-modified GO (C 7 GO)/SSBR composite had the smallest fractional free volume and the least mobility of the polymer chains. Moreover, the 1-octadecanethiol-modified GO (C 18 GO)/SSBR composite displayed the largest binding energy (E binding ). Thermal stability, gas barrier, dynamic, and static mechanical properties were improved by introducing C x GO. The long chain length of C x GO indicated that the composites had good performance. We believe that these results provide a basis for the design and fabrication of high-performance GO/SSBR composites. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
43. Solvent effect on electron transfer through alkanethiols.
- Author
-
Nikitina, Victoria A., Rudnev, Alexander V., Nazmutdinov, Renat R., Tsirlina, Galina A., and Wandlowski, Thomas
- Subjects
- *
SOLVENTS , *CHARGE exchange , *ALKANETHIOLS , *AQUEOUS solutions , *IONIC liquids - Abstract
The data on the rate constants for ferrocene/ferrocenium (Fc/Fc + ) electron transfer in ionic liquid 1-butyl-3-methyl imidazolium tetrafluoroborate ([bmim][BF 4 ]) are reported for a series of -S-(CH 2 ) n -Fc adlayers (n = 8…16) on polycrystalline gold. The values and trends are compared to the previously published data for similar series in aqueous medium, as well as to the results for ‘free’ Fc at -S-(CH 2 ) n − 1 -CH 3 modified gold in the same ionic liquid. For the latter case, the trend is opposite as compared to that in the available aqueous series (attached and ‘free’ ruthenium ammine complex): the ratio of rate constants for attached and ‘free’ reactants decreases with electrode-reactant distance in the former case, and increases in the latter. The presented comparison discovers the role of reactant and product work terms, which are essential for attached reactants as well because of conformational diversity. Corresponding contributions are estimated from molecular modeling and considered in terms of reaction volume. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
44. Modification of a Mercury Electrode with Different Thioalkanes: Structure‐Sensitive Bovine Serum Albumin Analysis.
- Author
-
Ostatná, Veronika, Černocká, Hana, Hasoň, Stanislav, and Paleček, Emil
- Subjects
MERCURY electrodes ,PROTEIN analysis ,ALKANETHIOLS ,ELECTROCHEMISTRY ,X-ray diffraction - Abstract
Abstract: Chronopotentiometric stripping (CPS) in combination with mercury electrodes is convenient for structure‐sensitive protein analysis. By using this method, we tested the discrimination between native and denatured bovine serum albumin (BSA) at various alkanethiol self‐assembled monolayers (SAMs). Our results showed that alkanethiol SAMs with different headgroups or different chain lengths had different influences on the efficiency of CPS in protecting BSA from the electric field‐induced denaturation. SAMs with longer alkanethiol chain lengths were more efficient in protecting BSA from denaturation at negatively charged electrode surface than those formed by short‐chain alkanethiols. Short alkanethiol SAMs could be prepared by co‐adsorption with the protein on the electrode surface, which was not possible with the long‐chain alkanethiols. CPS data were supported by impedance analysis. We believe that our work will be useful in the electrochemical sensing of nucleic acid‐protein and protein‐protein binding. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
45. Thiol‐ene photofunctionalization of 1,4‐polymyrcene.
- Author
-
Matic, Aleksandar and Schlaad, Helmut
- Subjects
ADDITION polymerization ,THIOGLYCOLIC acid ,BENZOPHENONES ,POLYMERIZATION ,ALKANETHIOLS ,PHOTOCHEMISTRY ,REGIOSELECTIVITY (Chemistry) - Abstract
Abstract: 1,4‐Polymyrcene was synthesized by anionic polymerization of β‐myrcene and was subjected to photochemical functionalization with various thiols (i.e. methyl thioglycolate, methyl 3‐mercaptopropionate, butyl 3‐mercaptopropionate, ethyl 2‐mercaptopropionate and 2‐methyl‐2‐propanethiol) using benzophenone/UV light as the radical source. The yield of thiol addition to the trisubstituted double bonds of 1,4‐polymyrcene decreased in the order 1° thiol (ca 95%) > 2° thiol (ca 80%) > 3° thiol (<5%), due to the reversibility of the thiol‐ene reaction. Remarkably, thiol addition to the side‐chain double bonds was 8 − 10 times (1° thiol) or 24 times (2° thiol) faster than to the main‐chain double bonds, which can be explained by the different accessibility of the double bonds and steric hindrance. Despite the use of a 10‐fold excess of thiol with respect to myrcene units, the thiol‐ene addition was accompanied by chain coupling reactions, which in the extreme case of 3° thiol (or in the absence of thiol) resulted in the formation of insoluble crosslinked material. As an example, a methyl‐thioglycolate‐functionalized 1,4‐polymyrcene was saponified/crosslinked to give submicron polyelectrolyte particles in dilute alkaline solution. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
46. Impact of gold-1-decanethiol-SAM formation and removal cycles on the surface properties of polycrystalline gold and SAM quality.
- Author
-
Thal, Dana, Kahlert, Heike, Chinnaya, Jeyabharathi, Ahrens, Paula, and Hasse, Ulrich
- Subjects
- *
ALKANETHIOLS , *REACTIVE oxygen species , *PHOTOLYSIS (Chemistry) , *HYDROGEN peroxide , *GOLD - Abstract
The impact of 1-decanethiol self-assembled monolayer (SAM) formation and removal cycles on polycrystalline Au surfaces and SAM quality was studied with the help of CV, DPV, Pb-UPD, STM, and AFM. The SAM removal was accomplished by dissolution with oxygen radicals generated by UV photolysis of aqueous hydrogen peroxide. During the first Au-SAM formation and removal cycles, the surface roughness decreased. After that, the surface properties remained almost unaffected, indicating that the cyclic treatment removed the most reactive gold surface sites, until a rather stable surface resulted, which guaranteed highly reproducible SAM formation. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
47. Hydrophilic surfaces via the self-assembly of nitrile-terminated alkanethiols on gold.
- Author
-
Park, Chul Soon, Zenasni, Oussama, Marquez, Maria D., Moore, H. Justin, and Lee, T. Randall
- Subjects
- *
HYDROPHILIC surfaces , *ALKANETHIOLS , *NITRILES - Abstract
A series of CN-terminated alkanethiols were synthesized and used to generate selfassembled monolayers (SAMs) on gold. The SAMs were characterized using ellipsometry, contact angle goniometry, polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), and X-ray photoelectron spectroscopy (XPS). The SAMs were compared to those derived from a series of analogous CH3-terminated alkanethiols. The CN-terminated SAMs exhibited lower film thicknesses than the CH3-terminated SAMs, which was largely due to their greater tilt angle on the surface. Additionally, the CN-terminated SAMs form well-ordered films on flat gold surfaces with relative packing densities being indistinguishable from the CH3-terminated SAMs. The CNterminated SAMs exhibited a less hydrophobic character than the SAMs derived from CH3- terminated adsorbates, which was attributed to the dipole moment of the terminal group as well as the lone pair of the nitrogen atom of the CN-terminal group. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
48. An integrated experimental-theoretical approach to understand the electron transfer mechanism of adsorbed ferrocene-terminated alkanethiol monolayers.
- Author
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Stragliotto, María F., Fernández, José L., Dassie, Sergio A., and Giacomelli, Carla E.
- Subjects
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ALKANETHIOLS , *FERROCENE , *MONOMOLECULAR films , *CHARGE exchange , *CYCLIC voltammetry , *ELECTROLYTES - Abstract
In this work, the electron transfer mechanism of self-assembled monolayers of 6-ferrocenyl-1-hexanethiol (FcC6SH) on Au(111) substrates is addressed from two perspectives. To acquire a complete overview of the involved pathways, cyclic voltammetry and scanning electrochemical microscopy (SECM) were combined using an integrated experimental-theoretical approach. In the first case, the electrochemical behaviour is evaluated in the light of computer simulations of the experimental voltammetric response measured at successive potential scans in different supporting electrolytes. Successive potential scans change the lateral interactions between adsorbed Fc molecules that affect the oxidation of the electroactive monolayer. Furthermore, ion-pair formation between the oxidized ferrocene moieties and the anions of the supporting electrolyte controls the electron transfer process as well as the type of the lateral interactions. In the second case, a thin-layer cell based formalism is used to develop a new model to understand feedback SECM experiments carried out with an additional redox mediator in solution. Since these experiments sense the parallel pathways of the electron transfer mechanism (pinholes and direct electron tunnelling and mediated electron transfer through the monolayer), the results are processed by using the new developed model for the analysis of the multipathway electron transfer mechanism. On that sense, the experimental results are processed by using the new SECM model accounting for the parallel electron transfer via the monolayer and the pinholes simultaneously. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
49. Two-Step Nanoscale Approach for Well-Defined Complex Alkanethiol Films on Au Surfaces.
- Author
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Neupane, S., Losada-Pérez, P., Vivegnis, S., Mekhalif, Z., Delhalle, J., Bashir, A., and Renner, F. U.
- Subjects
- *
ALKANETHIOLS , *GOLD nanoparticles , *COMPLEX compounds , *MOLECULAR self-assembly , *ATOMIC force microscopy - Abstract
Controlling the molecular organization of organic self-assembled monolayers (SAM) is of utmost importance in nanotechnology, molecular electronics, and surface science. Here we propose two well-differentiated approaches, double printing based on microcontact printing (μ-cp) and molecular backfilling adsorption, to produce complex alkanethiol films. The resulting films on model Au surfaces were characterized by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and contact angle measurements. Double printing alkanethiols results in clear coexisting regions where no molecular displacement is observed, highlighting the slow diffusion rates of long alkanethiols and large attractive interaction between long alkyl chains. Exposing a single-print μ-cp Au substrate to an additional alkanethiol solution yields the formation of differently ordered domain boundaries with different thickness and micrometer lateral size. The high order is a result of enhanced molecular mobility and restructuring during solution backfilling. The formed molecular assemblies constitute an excellent testing ground for nanoscale phenomena that strongly depend on the nanoscale geometrical and chemical features of the surface such as designed functionality or corrosion initiation and inhibition. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
50. Modification of surfaces of silver nanoparticles for controlled deposition of silicon, manganese, and titanium dioxides.
- Author
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Abdulrahman, Heman Burhanalden, Krajczewski, Jan, and Kudelski, Andrzej
- Subjects
- *
SILVER nanoparticles , *SILICA , *TITANIUM dioxide , *RAMAN spectroscopy , *ALKANETHIOLS - Abstract
In this work we show that nanometric-thick layers of SiO 2 , MnO 2 , and TiO 2 may be effectively deposited on various silver nanoparticles (including cubic Ag nanoparticles) covered by a very thin (below 0.4 nm) layer of silver sulphide. The background in Raman measurements generated by sulphide-protected Ag nanoparticles is significantly smaller than that for analogous Ag nanoparticles protected by a monolayer formed from alkanethiols – depositing alkanethiols on a surface of anisotropic silver nanoparticles is the current standard method used for protecting a surface of Ag nanoparticles before depositing a layer of silica. Because of significantly smaller generated Raman background, Ag@SiO 2 nanostructures with an Ag 2 S linkage layer between the silver core and the silica shell are very promising low-background electromagnetic nanoresonators for carrying out Raman analysis of various surfaces – especially using what is known as shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS). Sample SHINERS analyses of various surfaces (including pesticide-contaminated surfaces of tomatoes) using cubic-Ag@SiO 2 nanoparticles as electromagnetic nanoresonators are also presented. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
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