The synthesis and properties of iron, ruthenium, and osmium octabutoxynaphthalocyanine

2012 ◽  
Vol 16 (09) ◽  
pp. 1068-1071 ◽  
Author(s):  
Junhwan Kim ◽  
Malcolm E. Kenney
Keyword(s):  
Mass Spectrometry ◽  
Iron Complexes ◽  
Axial Ligand ◽  
Iron Complex ◽  
Free Iron ◽  
Metal Free ◽  
Ligand Free ◽  
The Stability

New series of iron, ruthenium, and osmium octabutoxynaphthalocyanines were synthesized by inserting corresponding metals into the metal-free octabutoxynaphthalocyanine. Although preparation of axial ligand-free iron octabutoxynaphthalocyanines was reported before, we could not reproduce the synthesis by following the reported method. We attributed the failure to the instability of the iron octabutoxynaphthalocyanines. Bis-ligation increased the stability of the iron complex but only sufficiently for characterization. The application of iron complexes will be limited by their instability. However, ruthenium and osmium formed stable complexes with this macrocycle ring but with significantly lower reaction yields. These new complexes were characterized by NMR, UV-vis, and mass spectrometry.

scholarly journals Application of Lipid Class Ratios for Sample Stability Monitoring—Evaluation of Murine Tissue Homogenates and SDS as a Stabilizer

Metabolites ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 277
Author(s):  
Sabrina Krautbauer ◽  
Raquel Blazquez ◽  
Gerhard Liebisch ◽  
Marcus Hoering ◽  
Philip Neubert ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Lipid Class ◽  
High Resolution Mass Spectrometry ◽  
Lipolytic Activity ◽  
Sodium Dodecyl ◽  
Lipid Profiles ◽  
Lipolytic Action ◽  
Sample Stability ◽  
Tissue Homogenates ◽  
The Stability

Lipids are a ubiquitous class of structurally complex molecules involved in various biological processes. In the fast-growing field of lipidomics, preanalytical issues are frequently neglected. Here, we investigated the stability of lipid profiles of murine liver, brain, lung, heart, and spleen homogenates by quantitative flow injection analysis using tandem mass spectrometry and high-resolution mass spectrometry. Storage of tissue homogenates at room temperature showed substantial alterations of the lipid profiles reflecting lipolytic action. Therefore, ratios of ceramide to sphingomyelin, lysophosphatidylethanolamine to phosphatidylethanolamine, lysophosphatidylcholine to phosphatidylcholine, and diglyceride to triglyceride were applied to monitor sample stability and the effect of sodium dodecyl sulfate (SDS) as a potential stabilizing agent. The addition of SDS led to a concentration-dependent stabilization of lipid profiles in liver, brain, and heart homogenates, while in lung and spleen homogenates, in particular, the lysophosphatidylethanolamine to phosphatidylethanolamine ratio increased upon addition of SDS. In conclusion, we demonstrated that lipid class ratios reflecting lipolytic activity could be applied to evaluate both the stability of samples and the influence of stabilizers.

scholarly journals Development and validation of the method for the detection of glimepiride via derivatization employing N-methyl-N-(trimethylsilyl) trifluoroacetamide using gas chromatography-mass spectrometry

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Priyanka Verma ◽  
Atul Bajaj ◽  
R. M. Tripathi ◽  
Sudhir K. Shukla ◽  
Suman Nagpal
Keyword(s):  
Diabetes Mellitus ◽  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Drug Users ◽  
Coefficient Of Determination ◽  
Gas Chromatography Mass Spectrometry ◽  
Biological Matrices ◽  
Chromatography Mass Spectrometry ◽  
Ms Analysis ◽  
The Stability

Abstract Background Recent advances in the diversified anti-diabetic drugs have appeared in the startling increase in the count of poisoning cases. The epidemics of diabetes mellitus are increasing; hence, the no. of anti-diabetic drug users raised by 42.9%. The use of glimepiride raised to 24%. As the toxicity and drug cases are also escalating with increasing epidemics of diabetes mellitus, a novel gas chromatography-mass spectrometry (GC-MS) method for detecting glimepiride in biological matrices is developed. Results Liquid-liquid extraction method was employed by using 1-butanol: hexane (50:50, v/v) under an alkaline medium, and then back extraction was done via acetic acid. Distinct derivatization techniques were employed for the sample preparation for GC-MS analysis, i.e., silylation and acylation. Derivatization approaches were optimized under different parameters, i.e., reaction temperature and reaction time. N-Methyl-N-(trimethylsilyl) trifluoroacetamide [MSTFA] was found to be the best sound derivatization reagent for the GC-MS analysis of glimepiride. Total ion current (TIC) mode was selected for the monitoring of ions of trimethylsilyl (TMS) derivative of glimepiride with an m/z ratio of 256. Distinct parameters like specificity, carryover, stability, precision, and accuracy were evaluated for validating the identification method. The GC-MS method is found to be linear and illustrated within the range 500 to 2500 ng/ml with the value of R2 (coefficient of determination) at 0.9924. The stability of the extracted and derivatized glimepiride was accessed with regard to processed/extracted sample conditions and autosampler conditions, respectively. Accuracy at each concentration level was within the + 15% of the nominal concentration. Precision (%) for the interday and intraday analysis was found to be in the respectable spectrum. Conclusion Henceforth, the proposed GC-MS method can be employed for the determination of glimepiride in biological matrices.

scholarly journals Neutrophil Gelatinase-Associated Lipocalin Expresses Antimicrobial Activity by Interfering with l-Norepinephrine-Mediated Bacterial Iron Acquisition

2010 ◽  
Vol 54 (4) ◽  
pp. 1580-1589 ◽  
Author(s):  
Marcus Miethke ◽  
Arne Skerra
Keyword(s):  
Iron Acquisition ◽  
Primary Source ◽  
Iron Complexes ◽  
Iron Complex ◽  
Immune Defense ◽  
Uptake System ◽  
Iron Chelate ◽  
Neutrophil Gelatinase Associated Lipocalin ◽  
Bacterial Uptake ◽  
Neutrophil Gelatinase

ABSTRACT l-norepinephrine (NE) is a neuroendocrine catecholamine that supports bacterial growth by mobilizing iron from a primary source such as holotransferrin to increase its bioavailability for cellular uptake. Iron complexes of NE resemble those of bacterial siderophores that are scavenged by human neutrophil gelatinase-associated lipocalin (NGAL) as part of the innate immune defense. Here, we show that NGAL binds iron-complexed NE, indicating physiological relevance for both bacterial and human iron metabolism. The fluorescence titration of purified recombinant NGAL with the FeIII·(NE)3 iron complex revealed high affinity for this ligand, with a K D of 50.6 nM. In contrast, the binding protein FeuA of Bacillus subtilis, which is involved in the bacterial uptake of triscatecholate iron complexes, has a K D for FeIII·(NE)3 of 1.6 μM, indicating that NGAL is an efficient competitor. Furthermore, NGAL was shown to inhibit the NE-mediated growth of both E. coli and B. subtilis strains that either are capable or incapable of producing their native siderophores enterobactin and bacillibactin, respectively. These experiments suggest that iron-complexed NE directly serves as an iron source for bacterial uptake systems, and that NGAL can function as an antagonist of this iron acquisition process. Interestingly, a functional FeuABC uptake system was shown to be necessary for NE-mediated growth stimulation as well as its NGAL-dependent inhibition. This study demonstrates for the first time that human NGAL not only neutralizes pathogen-derived virulence factors but also can effectively scavenge an iron-chelate complex abundant in the host.

Nucleophilic addition to di- and poly-iron arene complex cations

1996 ◽  
Vol 74 (11) ◽  
pp. 2073-2082 ◽  
Author(s):  
Alaa S. Abd-Ei-Aziz ◽  
Debbie A. Armstrong ◽  
Shelly Bernardin ◽  
Harold M. Hutton
Keyword(s):  
Nucleophilic Addition ◽  
Iron Complexes ◽  
Iron Complex ◽  
Cyanide Anion ◽  
Meta Position ◽  
Arene Complex ◽  
Nmr Techniques ◽  
Cyano Groups ◽  
Predominant Effect

Hydride and cyanide addition to a series of di- and polycyclopentadienyliron arene complex cations with etheric bridges is described. Reaction of the di-iron complexes with sodium borohydride resulted in the formation of a number of adducts.p-Methyl- and o,o-dimethylphenoxybenzene cyclopentadienyliron complexes were used as models in this study to allow for the characterization of the analagous di-iron complexes. The use of HH COSY and CH COSY NMR techniques enabled us to identify the isomeric nature of these adducts. The hydride addition results indicated that the etheric substituent had the predominant effect over the methyl group, leading to a higher addition ratio to the meta-, followed by the ortho-, then the para-positions. It was also clear that in the di-iron system, the hydride addition to each complexed arene ring took place independently. The addition of the cyanide anion to di- and poly-iron arene systems was more selective than that of the hydride anion. Reaction of sodium cyanide with p-methyl- or o-methyl-substituted arene complexes led to the formation of one adduct, with the cyanide being added to the meta position to the etheric bridges. However, cyanide addition to the di-iron complex, with a methyl substituent attached at the meta position of each complexed arene, led to the formation of a mixture of adducts. Cyanide addition to the poly-iron system with p-substituted arenes proved to be very selective, allowing for the formation of one adduct. Oxidative demetallation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) produced the uncomplexed polyaromatic ethers with cyano groups in a very good yield. Key words: cyclopentadienyliron, arene, nucleophilic addition, hydride, cyanide.

scholarly journals Mass Spectrometry Imaging Using Dynamically Harmonized FT-ICR at Million Resolving Power: Rationalizing and Optimizing Sample Preparation and Instrumental Parameters

2020 ◽  
Author(s):  
Mathieu Tiquet ◽  
Raphaël La Rocca ◽  
Daan van Kruining ◽  
Pilar Martinez-Martinez ◽  
Gauthier Eppe ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
High Resolution ◽  
Mass Spectrometry Imaging ◽  
Mass Range ◽  
Maldi Mass Spectrometry ◽  
Mass Accuracy ◽  
Ion Current ◽  
Resolving Power ◽  
Lipid Mass ◽  
The Stability

<p><i>MALDI mass spectrometry imaging (MSI) is a powerful analytical method giving access to the 2D localizations of compounds in a thin section of a sample. To properly discern isobaric compounds in complex biological samples, dynamically harmonized ICR cell (ParaCell©) has been introduce to achieve extreme spectral resolution. However, high resolution MS images realized on a 9.4T FTICR High resolution instrument with recommended parameters suffered from an abnormal shifting of m/z ratios pixel to pixel. Resulting datasets show poor mass accuracy measurements and resolutions under estimations. By following the behavior of the Total Ion Current in function of the number of laser shots, the abnormal mass shifting phenomenon has been linked to the stability of the Total Ion Current (TIC) during images acquisitions. An optimization of laser parameters is proposed in order to limit the observed mass shift to retain machine specifications during MSI analyses. It is also shown that the method has been successfully employed to realize quality MS images with resolution above 1,000,000 in the lipid mass range across the whole image.</i></p>

scholarly journals REDOX-REGULATION OF GELATINASES DURING GROWTH OF CISPLATIN-SENSITIVE AND RESISTANT GUERIN CARCINOMA

2015 ◽  
Vol 37 (1) ◽  
pp. 36-39
Author(s):  
A P Burlaka ◽  
I I Ganusevich ◽  
Yu V Lozovska ◽  
N Yu Lukianova ◽  
V F Chekhun
Keyword(s):  
Nadph Oxidase ◽  
Blood Serum ◽  
Tumor Cells ◽  
Redox Regulation ◽  
Tumor Tissue ◽  
Iron Complexes ◽  
Superoxide Radicals ◽  
Free Iron ◽  
Iron Pool ◽  
High Level

Study was aimed to analyze the dynamics of changes and study interrelations between content of ferritin, transferrin, active gelatinas es (MMP-2 and -9) in blood serum and tumor tissue, free iron, rate of superoxide radicals generation in tumor, activity of NADPH-oxidase and iNOS in neutrophils rats with sensitive and resistant strains of Guerin carcinoma (GC). Materials and Methods: In order to obtain resistant tumor, 12 courses of cisplatin chemotherapy have been carried out on rats bearing GC. Levels of transferrin and free iron were determined by analysis of EPR spectra from computerized radiospectrometer EPR R E-1307 at temperature of liquid nitrogen. Rate of superoxide radicals and nitric oxide generation in tumor and neutrophils of blood was determined by EPR using spin traps at room temperature. Content of ferritin in tumor homogenate and blood serum of rats with GC was determined by ELISA method using corresponding kits. Concentration of active forms of MMP-2 and -9 in obtained samples was determined using method of zymography. Results: Unregulated generation of superoxide radicals and NO by mitochondria of tumor cells and NADPH-oxidase and iNOS neutrophils via oxidation of iron-containing proteins causes the accumulation of “free iron” complexes in blood and tumor tissue of rats able to evoke oxide-induced damages of macromolecules. It has been shown that for resistant strain of carcinoma, as compared with sensitive one, significantly higher concentrations of active forms of MMP-2 and -9 in blood serum of rats are typical. Dynamics of gelatinases activity changes in tumor tissue corresponds in general with dynamics of changes in serum. In tumor tissue of rats the indices of gelatinases activity positively correlate with rate of superoxide radicals generation, content of “free iron” complexes, ferritin and activity of transferrin. Cytostatic agent increased levels of reactive oxygen species (ROS) and self-amplify rate of superoxide radicals generation. In turn, activation of MMPs via superoxide-depending regulation allows tumor cells to facilitate migration, invasion and finally — formation of metastatic centers. Mentioned above tumor “oxide phenotype” determines high level of its aggressiveness and forms corresponding level of drug resistance. Conclusions: Thus, high levels of superoxide radicals oxidize transport proteins and form free iron pool. Iron ions, via Haber — Weiss mechanism, initiate generation of the hydroxyl radicals, which also enhance oxidation processes.

scholarly journals The Copper(II) Ions Solvent Extraction with a New Compound: 2,6-Bis(4-Methoxybenzoyl)-Diaminopyridine

Processes ◽  
2019 ◽  
Vol 7 (12) ◽  
pp. 954 ◽  
Author(s):  
Daria Bożejewicz ◽  
Katarzyna Witt ◽  
Małgorzata A. Kaczorowska ◽  
Borys Ośmiałowski
Keyword(s):  
Mass Spectrometry ◽  
Solvent Extraction ◽  
High Resolution ◽  
Stability Constant ◽  
Tandem Mass Spectrometry ◽  
High Resolution Mass Spectrometry ◽  
Chloroform Solution ◽  
Tandem Mass ◽  
The Stability ◽  
Resolution Mass

A new compound 2,6-bis(4-methoxybenzoyl)-diaminopyridine (L) was used as an extractant for copper(II) ion recovery in a solvent extraction conducted at a temperature of 25 °C. The best results (99% recovery of copper(II) ions) were obtained when the aqueous phase contained 0.001 mol/dm3 Cu(II) and 0.2 mol/dm3 NH3 (pH~5.8), while the organic phase was a 0.001 mol/dm3 chloroform solution of 2,6-bis(4-methoxybenzoyl)-diaminopyridine. Spectrophotometry studies were used to determine the dissociation constant of the tested compound and determine the stability constant of the complex of subjected compound with copper(II) ions. The high-resolution mass spectrometry (HRMS) and higher energy collisional dissociation tandem mass spectrometry (HCD MS/MS) methods have been applied for the confirmation of the structure of 2,6-bis(4-methoxybenzoyl)-diaminopyridine and to determine its complexation with Cu(II) in solution.

All-PEGylated redox-active metal-free organic molecules in non-aqueous redox flow battery

2020 ◽  
Vol 8 (31) ◽  
pp. 15715-15724 ◽  
Author(s):  
Jingchao Chai ◽  
Amir Lashgari ◽  
Xiao Wang ◽  
Caroline K. Williams ◽  
Jianbing “Jimmy” Jiang
Keyword(s):  
Organic Molecules ◽  
Redox Flow Battery ◽  
Flow Battery ◽  
Active Materials ◽  
Metal Free ◽  
Redox Active ◽  
Active Metal ◽  
Molecular Sizes ◽  
The Stability ◽  
Redox Active Metal

A non-aqueous redox flow battery based on all-PEGylated, metal-free compounds is presented. The PEGylation enhances the stability of the redox-active materials, alleviating crossover by increasing the anolyte and catholyte species’ molecular sizes.

Thiyl radical promoted iron-catalyzed-selective oxidation of benzylic sp3 C–H bonds with molecular oxygen

2019 ◽  
Vol 55 (84) ◽  
pp. 12699-12702 ◽  
Author(s):  
Shasha Geng ◽  
Baojian Xiong ◽  
Yun Zhang ◽  
Juan Zhang ◽  
Yun He ◽  
...  
Keyword(s):  
Molecular Oxygen ◽  
Selective Oxidation ◽  
Thiyl Radical ◽  
Free Iron ◽  
Ligand Free

A ligand-free iron-catalyzed method for the oxygenation of benzylic sp3 C–H bonds by molecular oxygen (1 atm) using a thiyl radical as a cocatalyst has been developed.

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