scholarly journals Molecular Approach to Mesoporous Metal Sulfides

1994 ◽  
Vol 371 ◽  
Author(s):  
Mark T. Anderson ◽  
Paula Newcomer
Keyword(s):  
Metal Ions ◽  
Room Temperature ◽  
Negative Charge ◽  
Metal Sulfide ◽  
Metal Sulfides ◽  
Synthetic Approach ◽  
Divalent Metal Ions ◽  
Molecular Precursors ◽  
Mesoporous Metal ◽  
Cooperative Assembly

AbstractWe have synthesized metal-sulfide/surfactant nanocomposite materials by cooperative assembly of molecular precursors in an aqueous medium. The template-mediated synthetic approach is applicable to metal sulfides that exhibit aqueous thiometallate chemistry. The products are lamellar and have bilayers or interdigitated layers of surfactant molecules sandwiched between metal sulfide layers. The layers of anionic metal sulfide molecules are not completely condensed in the nanocomposites, which results in a negative charge on the metal sulfide layers. The materials are stable at room temperature in water, methanol, 1 M HCl, 30 wt% NH3, and 1 M NaOH. The materials do not dissolve at 80 °C in water and are stable to at least 180 0C in air. The nanocomposites exhibit ion exchange of smaller surfactants, alkali-metal ions, and divalent metal ions.

Multicomponent Polymerization of Alkynes, Sulfonyl Azide, and Iminophosphorane at Room Temperature for the Synthesis of Hyperbranched Poly(phosphorus amidine)s

Synlett ◽  
2018 ◽  
Vol 29 (19) ◽  
pp. 2523-2528 ◽  
Author(s):  
Rongrong Hu ◽  
Ben Tang ◽  
Liguo Xu ◽  
Kou Yang
Keyword(s):  
Metal Ions ◽  
Room Temperature ◽  
Platinum Group Metal ◽  
Hyperbranched Polymers ◽  
Synthetic Approach ◽  
Fluorescence Response ◽  
Topological Structures ◽  
Group Metal ◽  
Hyperbranched Poly ◽  
Sulfonyl Azide

The construction of functional hyperbranched polymers with unique topological structures and distinct properties remains a great challenge. Multicomponent polymerization, as a fascinating polymer synthetic approach, has proved to be a powerful tool for the synthesis of polymers with diverse structures and multifunctionalities, which is a great advantage for the preparation of hyperbranched polymers. In this work, a multicomponent polymerization of alkynes, sulfonyl azide, and iminophosphorane is utilized for the construction of heteroatom-rich hyperbranched poly(phosphorus amidine)s with different topological structures and fluorescence response toward platinum group metal ions.

A General Synthetic Approach for Ordered Mesoporous Metal Sulfides

2014 ◽  
Vol 136 (25) ◽  
pp. 8895-8898 ◽  
Author(s):  
Bryan T. Yonemoto ◽  
Gregory S. Hutchings ◽  
Feng Jiao
Keyword(s):  
Metal Sulfides ◽  
Synthetic Approach ◽  
Ordered Mesoporous ◽  
Mesoporous Metal

Catalytic Activity of Cu Ion-Exchanged Metalloaluminophosphates in NO Decomposition

1998 ◽  
Vol 63 (11) ◽  
pp. 1755-1768 ◽  
Author(s):  
Jiří Dědeček ◽  
Alena Vondrová ◽  
Jiří Čejka
Keyword(s):  
Catalytic Activity ◽  
Metal Ions ◽  
Molecular Sieves ◽  
Molecular Sieve ◽  
Negative Charge ◽  
Divalent Metal ◽  
No Decomposition ◽  
Divalent Metal Ions ◽  
Cu Ions

NO decomposition was investigated over Cu ion-exchanged aluminophosphate molecular sieve catalysts. Cu ions in cationic positions balanced by one framework negative charge in the metalloaluminophosphates of AlPO-5 and AlPO-11 structures exhibited catalytic activity in NO decomposition comparable with that of Cu-ZSM-5. No catalytic activity of the Cu ions incorporated during synthesis of molecular sieves into the framework in tetrahedral positions (CuAlPO-11) was observed. The catalytic activity of Cu-MeAlPO-5 and Cu-MeAlPO-11 was observed with various divalent metal ions of the MeAlPO-5 and MeAlPO-11 frameworks (Me = Zn, Mg, Fe, Co) and also with Cu exchanged SAPO-5 molecular sieves. The Cu-MeAlPO-5 and Cu-MeAlPO-11 catalysts differed only in the temperature of the maximum observed catalytic activity.

Interaction of divalent metal ions with the NADP+-malic enzyme from maize leaves

1991 ◽  
Vol 81 (4) ◽  
pp. 462-466 ◽  
Author(s):  
Maria Fabiana Drincovich ◽  
Alberto A. Iglesias ◽  
Carlos S. Andreo
Keyword(s):  
Metal Ions ◽  
Malic Enzyme ◽  
Divalent Metal ◽  
Divalent Metal Ions ◽  
Maize Leaves

A Highly Crystalline Anthracene-Based MOF-74 Series Featuring Electrical Conductivity and Luminescence

2019 ◽  
Author(s):  
Patricia Scheurle ◽  
Andre Mähringer ◽  
Andreas Jakowetz ◽  
Pouya Hosseini ◽  
Alexander Richter ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Metal Ions ◽  
Light Emission ◽  
Block Design ◽  
High Surface ◽  
Visible Spectrum ◽  
Building Blocks ◽  
Divalent Metal Ions ◽  
Conductivity Enhancement ◽  
Surface Areas

Recently, a small group of metal-organic frameworks (MOFs) has been discovered featuring substantial charge transport properties and electrical conductivity, hence promising to broaden the scope of potential MOF applications in fields such as batteries, fuel cells and supercapacitors. In combination with light emission, electroactive MOFs are intriguing candidates for chemical sensing and optoelectronic applications. Here, we incorporated anthracene-based building blocks into the MOF-74 topology with five different divalent metal ions, that is, Zn2+, Mg2+, Ni2+, Co2+ and Mn2+, resulting in a series of highly crystalline MOFs, coined ANMOF-74(M). This series of MOFs features substantial photoluminescence, with ANMOF-74(Zn) emitting across the whole visible spectrum. The materials moreover combine this photoluminescence with high surface areas and electrical conductivity. Compared to the original MOF-74 materials constructed from 2,5-dihydroxy terephthalic acid and the same metal ions Zn2+, Mg2+, Ni2+, Co2+ and Mn2+, we observed a conductivity enhancement of up to six orders of magnitude. Our results point towards the importance of building block design and the careful choice of the embedded MOF topology for obtaining materials with desired properties such as photoluminescence and electrical conductivity.

Kinetic Behaviour of Amylase According to pH: A New Perspective for Starch Hydrolysis Process

2020 ◽  
Vol 16 (2) ◽  
pp. 135-144
Author(s):  
Ravneet K. Grewal ◽  
Baldeep Kaur ◽  
Gagandeep Kaur
Keyword(s):  
Metal Ions ◽  
Competitive Inhibition ◽  
Deae Cellulose ◽  
Kinetic Studies ◽  
Cost Effective ◽  
Starch Hydrolysis ◽  
Divalent Metal Ions ◽  
Activity Data ◽  
Time Saving ◽  
Alkaline Conditions

Background: Amylases are the most widely used biocatalysts in starch saccharification and detergent industries. However, commercially available amylases have few limitations viz. limited activity at low or high pH and Ca2+ dependency. Objective: The quest for exploiting amylase for diverse applications to improve the industrial processes in terms of efficiency and feasibility led us to investigate the kinetics of amylase in the presence of metal ions as a function of pH. Methods: The crude extract from soil fungal isolate cultures is subjected to salt precipitation, dialysis and DEAE cellulose chromatography followed by amylase extraction and is incubated with divalent metal ions (i.e., Ca2+, Fe2+, Cu2+, and Hg2+); Michaelis-Menton constant (Km), and maximum reaction velocity (Vmax) are calculated by plotting the activity data obtained in the absence and presence of ions, as a function of substrate concentration in Lineweaver-Burk Plot. Results: Kinetic studies reveal that amylase is inhibited un-competitively at 5mM Cu2+ at pH 4.5 and 7.5, but non-competitively at pH 9.5. Non-competitive inhibition of amylase catalyzed starch hydrolysis is observed with 5mM Hg2+ at pH 9.5, which changes to mixed inhibition at pH 4.5 and 7.5. At pH 4.5, Ca2+ induces K- and V-type activation of amylase catalyzed starch hydrolysis; however, the enzyme has V-type activation at 7mM Ca2+ under alkaline conditions. Also, K- and V-type of activation of amylase is observed in the presence of 7mM Fe2+ at pH 4.5 and 9.5. Conclusion: These findings suggest that divalent ions modulation of amylase is pH dependent. Furthermore, a time-saving and cost-effective solution is proposed to overcome the challenges of the existing methodology of starch hydrolysis in starch and detergent industries.

scholarly journals Regulation of divalent metal ions to the aggregation and membrane damage of human islet amyloid polypeptide oligomers

RSC Advances ◽  
2021 ◽  
Vol 11 (21) ◽  
pp. 12815-12825
Author(s):  
Yajie Wang ◽  
Feihong Meng ◽  
Tong Lu ◽  
Chunyun Wang ◽  
Fei Li
Keyword(s):  
Metal Ions ◽  
Metal Binding ◽  
Membrane Damage ◽  
Islet Amyloid Polypeptide ◽  
Divalent Metal ◽  
Human Islet ◽  
Divalent Metal Ions ◽  
Islet Amyloid ◽  
Induced Membrane ◽  
Human Islet Amyloid Polypeptide

Their is a counteraction between a decrease in the disruptive ability of metal-associated oligomer species and an increase in the quantity of oligomers promoted by the metal binding in the activity of hIAPP induced membrane damage.

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