Nitrogen–Sulfur Ligand Systems via Reduction of Schiff's Base – Zinc Complexes Derived from Benzothiazolines

1974 ◽  
Vol 52 (7) ◽  
pp. 1054-1058 ◽  
Author(s):  
James L. Corbin ◽  
Dale E. Work
Keyword(s):  
Sodium Borohydride ◽  
Metal Ion ◽  
Chelating Agents ◽  
Chloroform Solution ◽  
Zinc Complexes ◽  
Schiff’S Base ◽  
Simple Route ◽  
Sulfur Ligand

The coordinated imine groups of the Schiff's base – zinc complexes derived from various 2-substituted benzothiazolines are easily reduced with sodium borohydride to the corresponding amines. Removal of the metal ion from these reduced complexes yields the free ligands, providing a simple route to novel aminomercaptan chelating agents. Compounds of bi-, tri-, and tetradentate types were prepared in this manner.Evidence is given for a disproportionation of 2,2′-dimethyl-2,2′-bibenzothiazolinyl into 2-methylbenzothiazoline and 2-methylbenzothiazole in chloroform solution.

scholarly journals Sodium borohydride (NaBH4) as a high-capacity material for next-generation sodium-ion capacitors

2021 ◽  
Vol 19 (1) ◽  
pp. 432-441
Author(s):  
Pawel Jeżowski ◽  
Olivier Crosnier ◽  
Thierry Brousse
Keyword(s):  
Energy Density ◽  
Sodium Borohydride ◽  
Metal Ion ◽  
High Capacity ◽  
Negative Electrode ◽  
Sodium Ion ◽  
Modern World ◽  
Next Generation ◽  
Good Efficiency ◽  
Voltage Range

Abstract Energy storage is an integral part of the modern world. One of the newest and most interesting concepts is the internal hybridization achieved in metal-ion capacitors. In this study, for the first time we used sodium borohydride (NaBH4) as a sacrificial material for the preparation of next-generation sodium-ion capacitors (NICs). NaBH4 is a material with large irreversible capacity of ca. 700 mA h g−1 at very low extraction potential close to 2.4 vs Na+/Na0. An assembled NIC cell with the composite-positive electrode (activated carbon/NaBH4) and hard carbon as the negative one operates in the voltage range from 2.2 to 3.8 V for 5,000 cycles and retains 92% of its initial capacitance. The presented NIC has good efficiency >98% and energy density of ca. 18 W h kg−1 at power 2 kW kg−1 which is more than the energy (7 W h kg−1 at 2 kW kg−1) of an electrical double-layer capacitor (EDLC) operating at voltage 2.7 V with the equivalent components as in NIC. Tin phosphide (Sn4P3) as a negative electrode allowed the reaching of higher values of the specific energy density 33 W h kg−1 (ca. four times higher than EDLC) at the power density of 2 kW kg−1, with only 1% of capacity loss upon 5,000 cycles and efficiency >99%.

scholarly journals Chelation and Metal-Ion Complex Formation of Chitosan Treated Cotton

2019 ◽  
Vol 8 (3) ◽  
pp. 93-100 ◽  
Author(s):  
Sudirman Habibie
Keyword(s):  
Cotton Fabric ◽  
Metal Ion ◽  
Chelating Agents ◽  
Transition Metal Ions ◽  
Cotton Fabrics ◽  
Carboxyl Groups ◽  
Polycarboxylic Acid ◽  
Salt Solutions ◽  
Polycarboxylic Acids ◽  
Zinc Salts

Chitin dan chitosan adalah bahan “chelate” yang sangat kuat untuk ion transisi logam terutama tembaga, nikel dan merkuri, dan sifat-sifat ini yang akan intensif di bahas. Pada studi ini kain kapas (cotton) dikerjakan dengan larutan chitosan-asam polikarboksilat untuk memperoleh kain kapas-chitosan yang mengandung gugus group karboksilat (-COOH) dan gugus amina (-NH2) fungsional. Penggunaan asam polykarboksilat (asam sitrat dan maleik) pada pelarutan chitosan menghasilkan group karboksil 0,5 meqs/g pada kain yang dicelup dengan larutan chitosan asam karboksilat. Kemudian kain kapas yang telah mengandung gugus karboksilat dan gugus amina ini dicelupkan pada larutan garam logam (garam tembaga dan seng). Terbukti bahwa larutan garam tembaga (copper) memberikan warna biru pada kain, hal ini mengindikasikan telah terjadi reaksi kompleks atau “Chelate”. Implikasi dari hasil ini maka diperkirakan kandungan group karboksil dan amina ini akan mempengaruhi pada pencelupan kain, namun hal ini tidak diuji.Kata kunci : Chitosan, Kain Kapas, Chelate, Asam asetat, Asam citrate, Asam maleik, Tembaga sulphate, Tembaga acetate.AbstractChitin and chitosan are powerfull chelating agents for transition metal ions, particularly copper, nickel and mercury, and these properties have been extensively reviewed. In this study, cotton fabric has been treated with chitosan- polycarboxylic acid solution to form chitosan treated cotton fabric containing carboxyl (-COOH) and amine (-NH2) functional groups. The use of polycarboxylic acids (citric and maleic acids) to dissolve chitosan has given carboxyl groups 0.5 meqs/g into chitosan treated cotton fabrics. Instead, the complexing of the treated cotton samples with copper and zinc salts was examined. The copper salt solutions gave blue fabrics confirming easily that complexing or chelation had occurred. There are implications for dyeing cotton making use of these groups but this was not investigated.Keyword : Chitosan, Cotton fabric, Chelation, Acetic acid, Citric acid, Maleic acid, Copper (II) sulphate, Copper (II) acetate.

scholarly journals Modification of plasma proteins by cigarette smoke as measured by protein carbonyl formation

1992 ◽  
Vol 286 (2) ◽  
pp. 607-611 ◽  
Author(s):  
A Z Reznick ◽  
C E Cross ◽  
M L Hu ◽  
Y J Suzuki ◽  
S Khwaja ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Human Plasma ◽  
Gas Phase ◽  
Cigarette Smoke ◽  
Plasma Proteins ◽  
Metal Ion ◽  
Chelating Agents ◽  
Protein Carbonyl ◽  
Plasma Damage ◽  
Carbonyl Formation

Exposure of human plasma to gas-phase (but not to whole) cigarette smoke (CS) produces oxidative damage to lipids [Frei, Forte, Ames & Cross (1991) Biochem. J. 277, 133-138], which is prevented by ascorbic acid. The ability of CS to induce protein damage was measured by the carbonyl assay and by loss of enzyme activity and protein -SH groups. Both whole and gas-phase CS caused formation of carbonyls in human plasma, which was partially inhibited by GSH but not by ascorbic acid or metal-ion-chelating agents. Isolated albumin exposed to CS showed much faster carbonyl formation (per unit protein) than did whole plasma; damage to isolated albumin was partially prevented by chelating agents. Isolated creatine kinase (CK) lost activity upon exposure to CS much faster than did CK in plasma. Direct addition to plasma of mixtures of some or all of the aldehydes reported to be present in CS caused protein carbonyl formation and inactivation of CK, but neither occurred to the extent produced by CS exposure.

Boron Hydrides. VII. The Metal Ion Catalyzed Hydrolysis of Sodium Borohydride in Heavy Water

1964 ◽  
Vol 3 (3) ◽  
pp. 460-461 ◽  
Author(s):  
Robert Earl Davis ◽  
Judith Ann Bloomer ◽  
David R. Cosper ◽  
Afif Saba
Keyword(s):  
Heavy Water ◽  
Sodium Borohydride ◽  
Metal Ion ◽  
Boron Hydrides ◽  
Hydrolysis Of

scholarly journals Sensing Zn2+ in Aqueous Solution with a Fluorescent Scorpiand Macrocyclic Ligand Decorated with an Anthracene Bearing Tail

Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1355 ◽  
Author(s):  
Matteo Savastano ◽  
Matteo Fiaschi ◽  
Giovanni Ferraro ◽  
Paola Gratteri ◽  
Palma Mariani ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Complex Formation ◽  
Metal Ion ◽  
Equilibrium Constants ◽  
Macrocyclic Ligand ◽  
Fluorescence Emission ◽  
Zinc Complexes ◽  
Large Excess ◽  
Macrocyclic Ring ◽  
Ph Range

Synthesis of the new scorpiand ligand L composed of a [9]aneN3 macrocyclic ring bearing a CH2CH2NHCH2-anthracene tail is reported. L forms both cation (Zn2+) and anion (phosphate, benzoate) complexes. In addition, the zinc complexes of L bind these anions. The equilibrium constants for ligand protonation and complex formation were determined in 0.1 M NaCl aqueous solution at 298.1 ± 0.1 K by means of potentiometric (pH-metric) titrations. pH Controlled coordination/detachment of the ligand tail to Zn2+ switch on and off the fluorescence emission from the anthracene fluorophore. Accordingly, L is able to sense Zn2+ in the pH range 6–10 down to nM concentrations of the metal ion. L can efficiently sense Zn2+ even in the presence of large excess of coordinating anions, such as cyanide, sulphide, phosphate and benzoate, despite their ability to bind the metal ion.

scholarly journals Chelating Agents and the Regulation of Metal Ions

1994 ◽  
Vol 1 (2-3) ◽  
pp. 87-106 ◽  
Author(s):  
Robert A. Bulman
Keyword(s):  
Metal Ion ◽  
Chelating Agents ◽  
Life Sciences ◽  
The Body ◽  
Imaging Procedures ◽  
Resonance Imaging ◽  
Ion Concentrations ◽  
Magnetic Resonance Imaging Mri ◽  
Oxidative Species ◽  
Moderate Length

Up to about the early 1980s it was perhaps still possible to summarize in a review of a moderate length the development of the medicinal applications of chelation chemistry and the exploitation of such chemistry in regulating the metal ion concentrations in the body. However, in the last few years there has a great surge in the development of chelation chemistry and its usage in medicine and related areas of life sciences research. It is no longer the case that such a review primarily concentrates upon the use of chelating agents in removing toxic metals from the body but it must now cover the use of chelating agents in the imaging procedures nuclear medicine and magnetic resonance imaging (MRI), the use of chelating agents in unravelling the biochemistry of reactive oxidative species (ROS) and the control and measurement of intracellular calcium ions. It is in the recent applications that there have been the greatest developments over the last ten years.

scholarly journals Spectroscopic evidence for a photosensitive oxygenated state of ammonia mono-oxygenase

1985 ◽  
Vol 226 (2) ◽  
pp. 499-507 ◽  
Author(s):  
J H Shears ◽  
P M Wood
Keyword(s):  
Metal Ion ◽  
Chelating Agents ◽  
Ammonia Oxidation ◽  
Resting Cells ◽  
Organic Substrates ◽  
Copper Proteins ◽  
Binuclear Copper ◽  
Oxidation Activity ◽  
Copper Site ◽  
Electron Reduction

Photoinactivation of ammonia oxidation by Nitrosomonas europaea cells by near-u.v. light was confirmed and further shown to occur with the same rate constant as loss of bromoethane-oxidation activity. Hydroxylamine oxidation was much less photosensitive. Protection against inactivation was afforded by anaerobiosis, organic substrates of ammonia mono-oxygenase such as bromoethane, or metal-ion-chelating agents such as thiourea. The presence of 10 mM-NH4+ or 1 mM-hydroxylamine made little difference, whereas hydrazine had a potentiating effect. Illumination of cells also caused a bleaching in the absorption spectrum around 380 nm, along with changes in the cytochrome gamma-band region. Similar effects below 400 nm were obtained when organic substrates and inhibitors of the mono-oxygenase were added to cells in the dark. The copper proteins haemocyanin and tyrosinase have a photosensitive oxygenated state with a near-u.v. absorption band of similar half-width. They also have a sensitivity to chelating agents similar to that of ammonia mono-oxygenase. The experimental results are explained in terms of a three-stage catalytic cycle analogous to that for tyrosinase. In resting cells most of the enzyme is believed to be in an oxygenated (Oxy) form, which absorbs maximally at 378 nm and is photosensitive. In the presence of a substrate, one O atom is inserted into the substrate and the other is reduced to water, leaving the enzyme in an oxidized (Met) state. This is followed by a two-electron reduction of the proposed binuclear copper site to give a reduced (Deoxy) state, which can bind O2 to complete the cycle.

scholarly journals Characterization of jack-bean α-D-mannosidase as a zinc metalloenzyme

1975 ◽  
Vol 147 (1) ◽  
pp. 83-90 ◽  
Author(s):  
S M Snaith
Keyword(s):  
Gel Electrophoresis ◽  
Metal Ion ◽  
Chelating Agents ◽  
Polyacrylamide Gel Electrophoresis ◽  
Gel Chromatography ◽  
Enzyme Molecule ◽  
Bivalent Metal ◽  
Jack Bean ◽  
Bivalent Metal Ions

1. Two methods were used to obtain α-mannosidase free from unbound Zn2+, (a) by removal of excess of metal ion from preparations purified in the presence of Zn2+ and (b) by purification under conditions that eliminate the need to add Zn2+. 2. The purified enzyme is homogeneous on ultracentrifugation, polyacrylamide-gel electrophoresis and gel chromatography. 3. The molecular weight is estimated to be 230 000. 4. The enzyme contains between 470 and 565 mug of zinc/g of protein, corresponding to between 1.7 and 2 atoms of zinc/enzyme molecule. The contents of other metals are much lower. 5. The enzyme is inactivated by chelating agents and activity is restored by Zn2+. 6. No other metal ion was found to replace Zn2+ with retention of activity. Some bivalent metal ions, e.g. Cu2+, rapidly inactivate the enzyme. 7. The results indicate that jack-bean α-mannosidase exists naturally as a zinc-protein complex and may be considered as a metalloenzyme.

Increase of Electrical Conductivity due to Chemical Reduction of Pre-Exfoliated Graphene Oxide by Sodium Borohydride

2015 ◽  
Vol 1117 ◽  
pp. 187-190 ◽  
Author(s):  
Astrida Berzina ◽  
Velta Tupureina ◽  
Raimonds Orlovs ◽  
Dmitrijs Saharovs ◽  
Juris Bitenieks ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Graphene Oxide ◽  
Sodium Borohydride ◽  
Metal Ion ◽  
Large Scale ◽  
Chemical Reduction ◽  
Reduction Process ◽  
Suspension Stability ◽  
Exfoliated Graphene ◽  
Reduced Graphene

Graphene oxide (GO) reduction is a promising way for graphene large scale synthesis. Pre-exfoliated graphite was oxidized and reduced. The material was compared to commercial graphene oxide and its reduced sample. The reduction process of graphene oxide is accomplished using sodium borohydride (NaBH4) with variable-valence metal ion – cobalt – assistance. The reduced graphene oxide (RGO) was characterized by Raman spectroscopy. The particle size and suspension stability were determined. Electrical conductivity measurements of GO and RGO samples have been done in temperature range from-150°C to 85°C. Pre-exfoliation effect was determined.

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