Protonation of Ferrocene Derivatives with Strong Acids. Kinetic Relationships of the Redox Isomerism of Ferrocenylcarbenium Ions

2020 ◽  
Vol 90 (6) ◽  
pp. 994-1001
Author(s):  
V. M. Fomin ◽  
A. V. Markin ◽  
N. N. Shuklina
Keyword(s):  
Ferrocene Derivatives ◽  
Redox Isomerism ◽  
Strong Acids

New Ferrocene Compounds as Selective Cyclooxygenase (COX-2) Inhibitors: Design, Synthesis, Cytotoxicity and Enzyme-inhibitory Activity

2018 ◽  
Vol 18 (2) ◽  
pp. 295-301 ◽  
Author(s):  
Shabnam Farzaneh ◽  
Elnaz Zeinalzadeh ◽  
Bahram Daraei ◽  
Soraya Shahhosseini ◽  
Afshin Zarghi
Keyword(s):  
Cell Lines ◽  
Inhibitory Activity ◽  
Fibroblast Cell ◽  
Breast Cancer Cell Lines ◽  
Ferrocene Derivatives ◽  
Cox 2 ◽  
Cytotoxicity Effects ◽  
Cox 2 Inhibitors ◽  
Mcf 7

Background: Due to the astonishing properties of ferrocene and its derivatives, it has a broad application in diverse areas. Numerous ferrocene derivatives demonstrated anti-proliferative activity. Also COX-2, as a key isoenzyme for production of prostaglandins, is frequently overexpressed in various cancers. It is now recognized that COX-2 over expression promotes tumorigenic functions which can be suppressed by COX-2 inhibitors, a phenomenon useful for the preventing of tumor progression. The combination of COX-2 inhibitors with other anti-cancer or cancer prevention drugs may reduce their side effects in future cancer prevention and treatment. Objective: Owing to high anticancer potential of ferrocene derivatives and considerable COX-2 inhibitory and cytotoxicity effects of our previously synthesized chalcones, we decided to incorporate the ferrocenyl moiety into appropriate COX-2 inhibitor chalcone based scaffold, to evaluate COX-2 inhibitory activity as well as anticancer activities. Methods: Chalcones were synthesized via clasien-schmidt condensation of methylsulfonyl aldehyde and acetyl ferrocene. Further different amines with solvent free and ultra sound condition were reacted with chalcones to have different 1-ferrocenyl-3-amino carbonyl compounds. Docking study was carried out with Auto Dock vina software. All the newly-synthesized compounds were evaluated for their cyclooxygenase-2 (COX-2) inhibitory activity using chemiluminescent enzyme assays as well as cytotoxicity activity against MCF-7 and T47D and fibroblast cell lines by MTT assay. Results: In vitro COX-1/COX-2 inhibition studies demonstrated that all compounds were selective inhibitors of the COX-2 isozyme with IC50 values in the highly potent 0.05-0.12 µM range, and COX-2 selectivity indexes (SI) in the 148.3-313.7 range. These results indicated that either potency or selectivity of COX-2 inhibitory activity was affected by the nature and size of the substituents on C-3 of propane-1-one. Also anti-proliferative and toxicity activities of synthesized compounds against breast cancer cell lines MCF-7 and T47D and fibroblast cell lines showed that the synthesized compounds had mild to moderate cytotoxicity against MCT7 and T47D breast cancer cell lines at 10 µM concentration. In vitro COX-1/COX-2 inhibition studies and anticancer activity against MCF-7, identified 1-ferrocenyl-3-(4-methylsulfonylphenyl) propen-1-one as a potent compound (IC50 COX-2 = 0.05 µM, MCF-7: % inhibition (at concentration of 10 µM) = 32.7%), and also 1-ferrocenyl-3- (propan-1-amine)-3-(4-methylsulfonylphenyl) propan-1-one showed the most selectivity on COX-2 inhibition (selectivity index= 313.7). Conclusion: A novel group of ferrocene compounds, possessing a methyl sulfonyl COX-2 pharmacophore were synthesized to investigate the effect of different substituents on selectivity and potency of COX-2 inhibitory activity and their cytotoxicity effects. This study indicates that 1-ferrocenyl-3-amino carbonyl compounds having ferrocene motif and methyl sulfonyl COX-2 pharmacophore is a suitable scaffold to design COX-2 inhibitors and anti-cancer agents.

Aqueous acid-aided corrosion products removal from the surface of the brass elements of heat exchangers

2019 ◽  
pp. 110-115
Author(s):  
L. M. Mironovich ◽  
A. Yu. Eliseev ◽  
A. Yu. Eliseeva
Keyword(s):  
Heat Exchangers ◽  
Solution Temperature ◽  
Cleaning Process ◽  
Complex Effect ◽  
Aqueous Acid ◽  
Surface Configuration ◽  
Additional Input ◽  
Heat Exchange Equipment ◽  
Working Solution ◽  
Strong Acids

The paper studies complex effect of various factors on the process of cleaning brass brand L-68, used for the manufacture of heat exchange equipment. It has been established that acids of various strengths can be used as working solutions. The speed of the cleaning process depends on the nature of the acid and its initial concentration. For strong acids, a working solution with low concentration is recommended, followed by an increase in their concentration during the cleaning process. Additional input of oxygen into the system and an increase of the working solution temperature increase the cleaning rate of brass. The cleaning process proceeds without significant changes in the surface configuration, and, consequently, the expenditure of metal.

Substituent effect on wave numbers of C=O valence vibrations in ferrocene derivatives

1983 ◽  
Vol 48 (6) ◽  
pp. 1635-1646 ◽  
Author(s):  
Alexander Perjéssy ◽  
Štefan Toma
Keyword(s):  
Linear Correlation ◽  
Substituent Effect ◽  
Empirical Relation ◽  
Ferrocene Derivatives ◽  
Wave Numbers ◽  
Complex Structural ◽  
Transmission Factors

Wave numbers of C=O valence vibrations of 83 ferrocene derivatives have been measured in tetrachloromethane. For a series of 154 compounds containing ferrocene skeleton linear correlation has been found between wave numbers of C=O vibration and X+(R) constants of structural fragments in the sense of modified and extended Seth-Paul-Van Duyse equation. Validity has been verified of the recently derived empirical relation for calculation of the X+(R) constants of complex structural fragments from values of constants of substituents and transmission factors for simple structural groupings. The transmission factors γ and π' for 1,3- and 1,1'-ferrocene system have been found to be well applicable to calculation of constants of structural fragments containing ferrocene skeleton.

Hydrophobic Ferrocene Derivatives as Potential Standards in Electrochemistry

1997 ◽  
Vol 62 (2) ◽  
pp. 185-198 ◽  
Author(s):  
Jaroslav Podlaha ◽  
Petr Štěpnička ◽  
Róbert Gyepes ◽  
Vladimír Mareček ◽  
Alexander Lhotský ◽  
...  
Keyword(s):  
Surface Tension ◽  
Cyclic Voltammetry ◽  
Redox Potential ◽  
Diffusion Coefficients ◽  
Carbon Electrodes ◽  
X Ray Diffraction ◽  
Ferrocene Derivatives ◽  
X Ray ◽  
Special Cases ◽  
As Solubility

Ferrocene (FcH) derivatives monosubstituted by palmitoyl (1), hexadecyl (2), 1-adamantoyl (3) or 1-adamantylmethyl (4) groups were sythesized and characterized by NMR, mass and 57Fe Mossbauer spectroscopy. The structure of 1-adamantoylferrocene was determined by single-crystal X-ray diffraction. Cyclic voltammetry on gold and glass-like carbon electrodes demonstrated that the compounds can serve as electrochemical standards for special cases since their ferrocene/ferricinium redox potential remains stable and reversible, while the properties such as solubility, diffusion coefficients and surface tension are strongly solvent-dependent.

scholarly journals Solvent-Controlled Self-Assembled Oligopyrrolic Receptor

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1771
Author(s):  
Fei Wang ◽  
Kejiang Liang ◽  
Mads Christian Larsen ◽  
Steffen Bähring ◽  
Masatoshi Ishida ◽  
...  
Keyword(s):  
Materials Science ◽  
Science Research ◽  
Polymeric Chain ◽  
Supramolecular System ◽  
Receptor System ◽  
One Dimensional ◽  
X Ray ◽  
Host Guest Complex ◽  
Colorimetric Response ◽  
Strong Acids

We report a fully organic pyridine-tetrapyrrolic U-shaped acyclic receptor 10, which prefers a supramolecular pseudo-macrocyclic dimeric structure (10)2 in a less polar, non-coordinating solvent (e.g., CHCl3). Conversely, when it is crystalized from a polar, coordinating solvent (e.g., N,N-dimethylformamide, DMF), it exhibited an infinite supramolecular one-dimensional (1D) “zig-zag” polymeric chain, as inferred from the single-crystal X-ray structures. This supramolecular system acts as a potential receptor for strong acids, e.g., p-toluenesulfonic acid (PTSA), methane sulfonic acid (MSA), H2SO4, HNO3, and HCl, with a prominent colorimetric response from pale yellow to deep red. The receptor can easily be recovered from the organic solution of the host–guest complex by simple aqueous washing. It was observed that relatively stronger acids with pKa < −1.92 in water were able to interact with the receptor, as inferred from 1H NMR titration in tetrahydrofuran-d8 (THF-d8) and ultraviolet–visible (UV–vis) spectroscopic titrations in anhydrous THF at 298 K. Therefore, this new dynamic supramolecular receptor system may have potentiality in materials science research.

DO WEAK OR STRONG ACIDS REMOVE CARBONATE CONTAMINATION FROM ANCIENT TOOTH ENAMEL MORE EFFECTIVELY? THE EFFECT OF ACID PRETREATMENT ON RADIOCARBON AND δ13C ANALYSES

Radiocarbon ◽  
2021 ◽  
pp. 1-18
Author(s):  
Rachel Wood ◽  
Andre Barros Curado Fleury ◽  
Stewart Fallon ◽  
Thi Mai Huong Nguyen ◽  
Anh Tuan Nguyen
Keyword(s):  
Acetic Acid ◽  
Chelating Agents ◽  
Tooth Enamel ◽  
Mineral Phase ◽  
Acid Pretreatment ◽  
Skeletal Material ◽  
Lower Porosity ◽  
Hot Environments ◽  
Strong Acids

ABSTRACT In hot environments, collagen, which is normally targeted when radiocarbon (14C) dating bone, rapidly degrades. With little other skeletal material suitable for 14C dating, it can be impossible to obtain dates directly on skeletal materials. A small amount of carbonate occurs in hydroxyapatite, the mineral phase of bone and tooth enamel, and has been used as an alternative to collagen. Unfortunately, the mineral phase is often heavily contaminated with exogenous carbonate causing 14C dates to underestimate the true age of a sample. Although tooth enamel, with its larger, more stable crystals and lower porosity, is likely to be more robust to diagenesis than bone, little work has been undertaken to investigate how exogenous carbonate can be effectively removed prior to 14C dating. Typically, acid is used to dissolve calcite and etch the surface of the enamel, but it is unclear which acid is most effective. This study repeats and extends earlier work using a wider range of samples and acids and chelating agents (hydrochloric, lactic, acetic and propionic acids, and EDTA). We find that weaker acids remove carbonate contaminants more effectively than stronger acids, and acetic acid is the most effective. However, accurate dates cannot always be obtained.

scholarly journals Occupations and exposure events in acute and subacute irritant-induced asthma

2021 ◽  
pp. oemed-2020-107323
Author(s):  
Irmeli Lindström ◽  
Jussi Lantto ◽  
Kirsi Karvala ◽  
Satu Soini ◽  
Katriina Ylinen ◽  
...  
Keyword(s):  
Acute Onset ◽  
High Exposure ◽  
Root Cause ◽  
Multiple Exposures ◽  
Lack Of Information ◽  
Hygiene Measures ◽  
Work Tasks ◽  
Causative Agents ◽  
Strong Acids ◽  
Normal Work

BackgroundExposures leading to irritant-induced asthma (IIA) are poorly documented.MethodsWe retrospectively screened the medical records of patients with IIA diagnosed in an occupational medicine clinic during 2000–2018. We classified the cases into acute (onset after single exposure) and subacute (onset after multiple exposures) IIA. We analysed in detail, occupations, causative agents and their air levels in the workplace, exposure events and the root causes of high exposure.ResultsAltogether 69 patients were diagnosed with IIA, 30 with acute and 39 with subacute IIA. The most common occupational groups were industrial operators (n=23, 33%), metal and machinery workers (n=16, 11%) and construction workers (n=12, 8%). Among industrial operators significantly more cases had subacute IIA than acute IIA (p=0.002). Forty cases (57%) were attributable to some type of corrosive acidic or alkaline chemical. Acute IIA followed accidents at work in different types of occupation, while subacute IIA was typical among industrial operators performing their normal work tasks under poor work hygiene conditions. The most common root cause was lack of information or false guidance in acute IIA (n=11, 36%) and neglect of workplace hygiene measures in subacute IIA (n=29, 74%).ConclusionsAccidents are the main causes of acute IIA, whereas subacute IIA can develop in normal work in risk trades with poor work hygiene. Airborne strong acids or bases seem to be the most important causative agents of acute and subacute IIA. The different risk profiles of acute and subacute IIA should be considered in the prevention and identification of the cases.

scholarly journals An Electrochemical Evaluation of Novel Ferrocene Derivatives for Glutamate and Liver Biomarker Biosensing

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 254
Author(s):  
Geok Hong Soon ◽  
Mary Deasy ◽  
Eithne Dempsey
Keyword(s):  
Film Studies ◽  
Redox Potentials ◽  
Signal Loss ◽  
Electronic Effects ◽  
Ferrocene Derivatives ◽  
Electroactive Films ◽  
Glutamate Oxidase ◽  
Electronic Effects Of Substituents ◽  
Glutamyl Transpeptidase

Here, we present an evaluation of two new monosubstituted ferrocene (Fc) derivatives, 3-(1H-pyrrol-1-yl)propanamidoferrocene and 1-hydroxy-2-[2-(thiophen-3-yl)-ethylamino]ethylferrocene, as glutamate oxidase mediators, together with their preparation and characterisation. Taking into consideration the influence of the electronic effects of substituents on the redox potentials of the Fc species, two candidates with pyrrole or thiophene moieties were proposed for investigation. Film studies involved potential sweeping in the presence of pyrrole or 3,4-ethylenedioxythiophene monomers resulting in stable electroactive films with % signal loss upon cycling ranging from 1 to 7.82% and surface coverage (Γ) 0.47–1.15 × 10−9 mol/cm2 for films formed under optimal conditions. Construction of a glutamate oxidase modified electrode resulted in second-generation biosensing with the aid of both cyclic voltammetry and hydrodynamic amperometry, resulting in glutamate sensitivity of 0.86–1.28 μA/mM and Km (app) values over the range 3.67–5.01 mM. A follow-up enzyme assay for liver biomarker γ-glutamyl transpeptidase realised unmediated and mediated measurement establishing reaction and incubation time investigations and a realising response over <100 U/L γ-glutamyl transpeptidase with a sensitivity of 5 nA/UL−1.

scholarly journals The Activating Effect of Strong Acid for Pd-Catalyzed Directed C–H Activation by Concerted Metalation-Deprotonation Mechanism

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4083
Author(s):  
Heming Jiang ◽  
Tian-Yu Sun
Keyword(s):  
Activation Energy ◽  
Dft Calculations ◽  
Energy Barrier ◽  
Computational Study ◽  
Strong Acid ◽  
Activation Energy Barrier ◽  
Pd Catalysts ◽  
Acid Ligand ◽  
Strong Acids

A computational study on the origin of the activating effect for Pd-catalyzed directed C–H activation by the concerted metalation-deprotonation (CMD) mechanism is conducted. DFT calculations indicate that strong acids can make Pd catalysts coordinate with directing groups (DGs) of the substrates more strongly and lower the C–H activation energy barrier. For the CMD mechanism, the electrophilicity of the Pd center and the basicity of the corresponding acid ligand for deprotonating the C–H bond are vital to the overall C–H activation energy barrier. Furthermore, this rule might disclose the role of some additives for C–H activation.

Ionization of moderately strong acids in aqueous solution. I. Trifluoro- and trichloroacetic acids

1970 ◽  
Vol 74 (21) ◽  
pp. 3773-3780 ◽  
Author(s):  
Arthur K. Covington ◽  
J. G. Freeman ◽  
T. H. Lilley
Keyword(s):  
Aqueous Solution ◽  
Strong Acids
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