scholarly journals Size and charge effect of guest cations in the formation of polyoxopalladates: a theoretical and experimental study

2017 ◽  
Vol 8 (11) ◽  
pp. 7862-7872 ◽  
Author(s):  
Zhongling Lang ◽  
Peng Yang ◽  
Zhengguo Lin ◽  
Likai Yan ◽  
Ming-Xing Li ◽  
...  
Keyword(s):  
Experimental Study ◽  
Metal Ion ◽  
Experimental Techniques ◽  
Central Metal ◽  
Charge Effect ◽  
Inorganic Clusters

The close interplay of theoretical and experimental techniques can facilitate the understanding and rational synthesis of novel inorganic clusters, and here an impressive example is shown for the class of cuboid-shaped polyoxo-12-palladates(ii) with a central metal ion guest.

Protonation effects on dynamic flux properties of aqueous metal complexes

2009 ◽  
Vol 74 (10) ◽  
pp. 1543-1557 ◽  
Author(s):  
Herman P. Van Leeuwen ◽  
Raewyn M. Town
Keyword(s):  
Complex Formation ◽  
Metal Ion ◽  
Good Description ◽  
Minor Component ◽  
Outer Sphere ◽  
Metal Species ◽  
Central Metal ◽  
Inner Sphere ◽  
A Minor ◽  
Protonated Ligand

The degree of (de)protonation of aqueous metal species has significant consequences for the kinetics of complex formation/dissociation. All protonated forms of both the ligand and the hydrated central metal ion contribute to the rate of complex formation to an extent weighted by the pertaining outer-sphere stabilities. Likewise, the lifetime of the uncomplexed metal is determined by all the various protonated ligand species. Therefore, the interfacial reaction layer thickness, μ, and the ensuing kinetic flux, Jkin, are more involved than in the conventional case. All inner-sphere complexes contribute to the overall rate of dissociation, as weighted by their respective rate constants for dissociation, kd. The presence of inner-sphere deprotonated H2O, or of outer-sphere protonated ligand, generally has a great impact on kd of the inner-sphere complex. Consequently, the overall flux can be dominated by a species that is a minor component of the bulk speciation. The concepts are shown to provide a good description of experimental stripping chronopotentiometric data for several protonated metal–ligand systems.

Effects of substituent groups and central metal ion on hydrogen adsorption in zeolitic imidazolate frameworks

2013 ◽  
Vol 97 ◽  
pp. 60-66 ◽  
Author(s):  
Er-Yu Chen ◽  
Ying-Chun Liu ◽  
Tian-Yang Sun ◽  
Qi Wang ◽  
Li-Jun Liang
Keyword(s):  
Metal Ion ◽  
Hydrogen Adsorption ◽  
Central Metal ◽  
Zeolitic Imidazolate Frameworks

MetLigDB: a web-based database for the identification of chemical groups to design metalloprotein inhibitors

2011 ◽  
Vol 44 (4) ◽  
pp. 878-881 ◽  
Author(s):  
Hwanho Choi ◽  
Hongsuk Kang ◽  
Hwangseo Park
Keyword(s):  
Drug Discovery ◽  
Metal Ions ◽  
Metal Ion ◽  
Central Metal ◽  
Amino Acid Residues ◽  
Web Based ◽  
Additional Information ◽  
Chemical Groups ◽  
Insight Into ◽  
Chelating Groups

MetLigDB (http://silver.sejong.ac.kr/MetLigDB) is a publicly accessible web-based database through which the interactions between a variety of chelating groups and various central metal ions in the active site of metalloproteins can be explored in detail. Additional information can also be retrieved, including protein and inhibitor names, the amino acid residues coordinated to the central metal ion, and the binding affinity of the inhibitor for the target metalloprotein. Although many metalloproteins have been considered promising targets for drug discovery, it is difficult to discover new inhibitors because of the difficulty in designing a suitable chelating moiety to impair the catalytic activity of the central metal ion. Because both common and specific chelating groups can be identified for varying metal ions and the associated coordination environments, MetLigDB is expected to give users insight into designing new inhibitors of metalloproteins for drug discovery.

Philosophy of Neuroscience

2016 ◽  
Author(s):  
Adina L. Roskies ◽  
Carl F. Craver
Keyword(s):  
Experimental Study ◽  
Experimental Techniques ◽  
Central Research ◽  
Philosophy Of Neuroscience ◽  
The Past ◽  
Research Areas ◽  
Potential Impact ◽  
Rich Material ◽  
The Mind ◽  
The Brain

The experimental study of the brain has exploded in the past several decades, providing rich material for both philosophers of science and philosophers of mind. In this chapter, the authors summarize some central research areas in philosophy of neuroscience. Some of these areas focus on the internal practice of neuroscience, that is, on the assumptions underlying experimental techniques, the accepted structures of explanations, the goals of integrating disciplines, and the possibility of a unified science of the mind-brain. Other areas focus outwards on the potential impact that neuroscience is having on our conception of the mind and its place in nature.

scholarly journals Synthesis, characterization and antibacterial activity of metalloporphyrins: Role of central metal ion

2020 ◽  
Vol 2 ◽  
pp. 100073
Author(s):  
Belete B. Beyene ◽  
Ayenew M. Mihirteu ◽  
Misganaw T. Ayana ◽  
Amogne W. Yibeltal
Keyword(s):  
Antibacterial Activity ◽  
Metal Ion ◽  
Central Metal

On the Kinetics and Mechanism of Spontaneous Intramolecular Reduction of the Central Metal Ion in K2[Mn(IV)-2-α-hydroxyethyl isochlorin e4] Acetate in Aqueous Alkaline Solutions and its Relation to the Binding Sites of Manganese in Photosynthesis

1975 ◽  
Vol 30 (5-6) ◽  
pp. 327-332 ◽  
Author(s):  
Gerhard Vierke ◽  
Manfred Müller
Keyword(s):  
Electron Transfer ◽  
Metal Ion ◽  
Reaction Rates ◽  
Bimolecular Reaction ◽  
Reduction Reaction ◽  
Alkaline Solutions ◽  
Central Metal ◽  
Pseudo First Order Reaction ◽  
Spontaneous Reduction ◽  
Acid Base Equilibrium

Abstract Spectrophotometric investigation of the kinetics of the spontaneous reduction of the central metal ion in K2[Mn (IV)-2-α-hydroxyethyl-isochlorine e4] acetate in aqueous alkaline solution in the absence of any reducing agent reveals that it is a pseudo-first order reaction which is specifically hydroxide ion catalyzed. The pKα-value of the acid-base equilibrium has been estimated to be 14.4. Electron transfer to the central metal ion is the rate limiting step. The measurements of its temperature dependence yields an activation enthalpy of ∆H‡ = 12 kcal/mol and an entropy of activation ∆S‡ = - 30 e.u. thus indicating that the electron transfer step is a bimolecular reaction. The most likely reactant is water. The reduction reaction does not take place with appreciable reaction rates at physiological pH. Thus, when bound to a suitable ligand of the chlorin type, Mn (IV)-compounds are sufficiently stable with respect to autoxidation to play some role in biological redox reactions as postulated recently for the photoreactivation process of the water splitting system in photosynthesis.

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