scholarly journals Transition Metal Ions as Efficient Catalysts for Facile Ortho-Formylation of Phenols under Vilsmeier–Haack Conditions

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
F. Aneesa ◽  
K. C. Rajanna ◽  
Y. Arun Kumar ◽  
M. Arifuddin
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Aromatic Compounds ◽  
Metal Ion ◽  
Transition Metal Ions ◽  
Efficient Condition

Aromatic compounds (phenols), when treated with Vilsmeier Haack (V-H) reagent in the presence of transition metal ions such as Cu(II), Ni(II), Co(II), Cd(II), and Zn(II) under reflux conditions, afforded corresponding ortho-formyl derivatives in good yields. Under normal conditions the metal-ion-free V-H reactions are too sluggish and resulted in poor yields. This protocol provides highly regioselective formylation under a mild and efficient condition with simple workup.

2,2î-Bipyridine Catalyzed Bleaching of Cotton Fibers with Peracetic Acid

1988 ◽  
Vol 58 (4) ◽  
pp. 198-210 ◽  
Author(s):  
James W. Rucker ◽  
David M. Cates
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Peracetic Acid ◽  
Metal Ion ◽  
Solution Treatment ◽  
Transition Metal Ions ◽  
Ferrous Ion ◽  
Cotton Fibers ◽  
Lauryl Sulfate ◽  
Ferrous Ions

Peracetic acid can be catalyzed to bleach cotton fibers at temperatures as low as 30°C by incorporating 2,2î-bipyridine in the bleach solution. Treatment of the fibers with HCl prior to bleaching reduces bleaching effectiveness by removing trace transition metal ions from the fibers. Sorption of individual ions (Cr+3 Mn+2, Fe+2, Fe+3 Co+2, Ni+2, Cu+2, and Zn+2) by HCl treated cotton fibers prior to bleaching indicates that the ferrous ion produces the greatest catalytic effect, and it is only effective when the metal ion is in the fiber as opposed to in solution. Ferrous ions in the fibers sorb 2,2î-bipyridine from solution to form the tris-2,2î-bipyridine ferrous ion complex that is associated with the fibers, and it is the trischelate associated with the fibers that catalyzes bleaching. The effects of pH, temperature, and concentrations of 2,2î-bipyridine, sodium lauryl sulfate, and transition metal ions (in the fibers and in solution) on bleaching effectiveness and peracetic acid decomposition have been studied, and a bleaching mechanism is proposed.

Intermediate-stage transition metal ion exchange in a zeolite X

1982 ◽  
Vol 35 (7) ◽  
pp. 1335 ◽  
Author(s):  
M Chatterjee ◽  
D Ganguli
Keyword(s):  
Ion Exchange ◽  
Transition Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
Intermediate Stage ◽  
Transition Metal Ions ◽  
Zeolite X ◽  
Counter Ions ◽  
Metal Ion Exchange ◽  
Exchange Behaviour

The exchange behaviour of some divalent transition metal ions M2+ (Zn2+, Cu2+, Ni2+, Co2+, Mn2+) in a zeolite NaX (SiO2/Al2O3 2.75) was studied at intermediate stages before equilibrium. The equivalent counter ion supply in the solution, given by the equivalent ratio of the two counter ions 2M2+/Na+, was found to be critical in determining the saturation level of exchange. The series of relative abilities of exchange was very similar to the well known selectivity series at equilibrium. It is suggested that water exchange of the metal ions in solution could be one of the factors controlling the relative ease of ion exchange.

Layered Tungsten Oxide-Based Hybrid Materials Incorporating Transition Metal Ions

2004 ◽  
Vol 847 ◽  
Author(s):  
Bridget Ingham ◽  
S. V. Chong ◽  
Jeff L. Tallon
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Tungsten Oxide ◽  
Hybrid Materials ◽  
Transition Metal Oxides ◽  
Metal Ion ◽  
Interlayer Spacing ◽  
Transition Metal Ions ◽  
Ferromagnetic Transition ◽  
Inorganic Framework

ABSTRACTLayered organic-inorganic hybrid materials based on tungsten oxide as the inorganic framework have been synthesised to include transition metal ions. The resulting materials have been characterised using a number of techniques. X-ray diffraction shows an interlayer expansion with increasing alkyl length. Infrared vibrational spectra of manganese tungstate compounds indicate the organic amine molecules are neutrally charged, and the inorganic framework is unaltered as one varies the organic intercalate. The magnetic behaviour of the materials has also been explored using a SQUID magnetometer. In the manganese tungstate hybrids an antiferromagnetic (AF) transition is observed, which decreases in temperature as the inorganic interlayer spacing is increased. A nickel tungstate hybrid sample, on the other hand, displays a ferromagnetic transition, which we attribute to a canted AF phase below 15 K. In all cases studied, the behaviour can be mapped to an effective moment (Peff) per transition metal ion, which agrees well with theoretical and literature values for other transition metal oxides.

scholarly journals Possible Action of Transition Divalent Metal Ions at the Inter-Pentameric Interface of Inactivated Foot-and-Mouth Disease Virus Provide A Simple but Effective Approach to Enhance Stability

2021 ◽  
Author(s):  
Xuan Lin ◽  
Yanli Yang ◽  
Yanmin Song ◽  
Shuai Li ◽  
Xuan Zhang ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Disease Virus ◽  
Specific Antibody ◽  
Metal Ion ◽  
Foot And Mouth Disease ◽  
Transition Metal Ions ◽  
Mouth Disease ◽  
Transition Metal Ion ◽  
Mouth Disease Virus

The structural instability of inactivated foot-and-mouth disease virus (FMDV) hinders the development of vaccine industry. Here we found that some transition metal ions like Cu2+ and Ni2+ could specifically bind to FMDV capsids at capacities about 7089 and 3448 metal ions per capsid, respectively. These values are about 33- and 16-folds of the binding capacity of non-transition metal ion Ca2+ (about 214 per capsid). Further thermodynamic studies indicated that all these three metal ions bound to the capsids in spontaneous enthalpy driving manners (ΔG<0, ΔH<0, ΔS<0), and the Cu2+ binding had the highest affinity. The binding of Cu2+ and Ni2+ could enhance both the thermostability and acid-resistant stability of capsids, while the binding of Ca2+ was helpful only to the thermostability of the capsids. Animal experiments showed that the immunization of FMDV bound with Cu2+ induced the highest specific antibody titers in mice. Coincidently, the FMDV bound with Cu2+ exhibited significantly enhanced affinities to integrin β6 and heparin sulfate, both of which are important cell surface receptors for FMDV attaching. Finally, the specific interaction between capsids and Cu2+ or Ni2+ was applied to direct purification of FMDV from crude cell culture feedstock by the immobilized metal affinity chromatography. Based on our new findings and structural analysis of the FMDV capsid, a “transition metal ion bridges” mechanism that describes linkage between adjacent histidine and other amino acids at the inter-pentameric interface of the capsids by transition metal ions coordination action was proposed to explain their stabilizing effect imposed on the capsid. IMPORTANCE How to stabilize the inactivated FMDV without affecting virus infectivity and immunogenicity is a big challenge in vaccine industry. The electrostatic repulsion induced by protonation of a large amount of histidine residues at the inter-pentameric interface of viral capsids is one of the major mechanisms causing the dissociation of capsids. In the present work, this structural disadvantage inspired us to stabilize the capsids through coordinating transition metal ions with the adjacent histidine residues in FMDV capsid, instead of removing or substituting them. This approach was proved effective to enhance not only the stability of FMDV, but also enhance the specific antibody responses; thus, providing a new guideline for designing an easy-to-use strategy suitable for large-scale production of FMDV vaccine antigen.

scholarly journals Kinetics of Transition Metal Ion Catalyzed Oxidation of some Industrially Important Alcohols using Ammonium Meta Vanadate in Acidic Medium

2020 ◽  
pp. 35-41
Author(s):  
Harichandra A Parbat ◽  
D V Prabhu ◽  
Anna Pratima Nikalje
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Acidic Medium ◽  
Metal Ion ◽  
Crop Protection ◽  
Transition Metal Ions ◽  
Primary Alcohols ◽  
Oxidation Of Alcohols ◽  
Ammonium Meta Vanadate ◽  
Kinetics Of

Oxidation of alcohols has industrial importance as it yields several useful products.Toxic and costly metal ions like Os(VIII), Cr(VI), and Ru in different oxidation states are widely used for the oxidation of a variety of organic compounds. We are reporting herein the oxidation of the industrially useful primary alcohols, 2-Chloroethanol, 2-Butoxyethanol and 2-Phenoxyethanol using Ammonium metavanadate in acidic medium. Relatively less toxic and cheaper transition metal ions of the first series are effectively used as homogeneous catalysts for the oxidation of the alcohols to the corresponding aldehydes. 2- Chloroethanol is used as a precursor for ethylene oxide and is useful in the manufacture of crop protection chemicals, and pharmaceuticals.2-Butoxyethanol finds use in the making of paints, varnishes and industrial and household cleaners.

Stabilization and Protection of Biomaterial through Biomineralization via Surface Interaction: An Astrobiological Approach

2018 ◽  
Author(s):  
Preeti Bhatt ◽  
Chandra Kala Pant ◽  
Pramod Pandey ◽  
Yogesh Pandey ◽  
Satish Chandra Sati ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Metal Ion ◽  
Transition Metal Ions ◽  
Living System ◽  
Stable Complex ◽  
Adsorption Parameters ◽  
Spectral Techniques ◽  
Prebiotic Chemical ◽  
Free Environment

A Cytosine (CYN), core constituent of both RNA and DNA, is a well-known functional biomaterial of living system. Adsorption of such molecule on primigenial mineral surfaces transacts a very specific and selective role in biocompatibility and biomineralization. The adsorption behaviour of CYN, with change in pH, concentration, time and temperature on siliceous Montmorillonite (MMT) surface, a prominent nanoclay of smectite group with specific surface area, was studied systematically and methodically using different spectral techniques (viz. UV, FTIR, SEM and XRD). Biogenic metal dication [M2+= Mg2+, Ca2+, Fe2+ and Cu2+] entrapped nanocomposites of MMT were prepared separately by cation-exchange approach. The results reveal significant role of MMT and biogenic metal ions on the quantity of CYN adsorbed. The adsorption isotherm elegantly evinces monolayer formation of the biomaterial on the surface of MMT and MMT-M2+. The Langmuir adsorption parameters (KL &amp; Xm) delineated appreciable interaction of CYN on MMT-Fe2+ surface as compared to MMT alone and other metal confined MMTs. The present work throws light on affinity of MMT nanoclay (having multifarious applications in biological systems) involving biogenic metal ions on stabilization and protection of biomaterials through biomineralization during prebiotic chemical evolution of biomolecules. The results embarks better adsorption capability of transition metal ion incorporated MMT than the clay without metal ion and with alkaline Earth dications due to better coordination properties of transition metal ions involving their d-orbitals for stable complex formation with negative sites of cytosine molecules as ligands. Since metal ions are key components of various enzymes which can catalyse a number of biochemical reactions in the living systems, the present study give better understanding regarding the pathways of aggregation of biomonomers on solid surfaces which themselves might have catalysed the formation of complex biomolecules via polymerization and condensation in enzyme free environment of early Earth and also influences implant biocompatibility.

Pentafluorophenyl dipyrrin as probe for transition metal ion detection and bioremediation in Bacillus subtilis and Bacillus cereus

2017 ◽  
Vol 41 (19) ◽  
pp. 11190-11200 ◽  
Author(s):  
Dijo Prasannan ◽  
Chellaiah Arunkumar
Keyword(s):  
Bacillus Subtilis ◽  
Transition Metal ◽  
Metal Ions ◽  
Bacillus Cereus ◽  
Metal Ion ◽  
Transition Metal Ions ◽  
Ion Detection ◽  
Transition Metal Ion ◽  
Metal Ion Detection

Recognition of transition metal ions and bioaccumulation in B. subtilis and B. cereus were examined using pentafluorophenyl dipyrrin probe.

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