scholarly journals Preparation of metallosupramolecular single-chain polymeric nanoparticles and their characterization by Taylor dispersion

2020 ◽  
Vol 11 (2) ◽  
pp. 586-592 ◽  
Author(s):  
Laura N. Neumann ◽  
Dominic A. Urban ◽  
Philipp Lemal ◽  
Sushila Ramani ◽  
Alke Petri-Fink ◽  
...  
Keyword(s):  
Complex Formation ◽  
Metal Ions ◽  
Polymeric Nanoparticles ◽  
Taylor Dispersion ◽  
Dispersion Analysis ◽  
Single Chain ◽  
Ligand Complex ◽  
Dispersed Particles ◽  
Metal Ligand

Polymers with pendant ligands furnish single-chain polymeric nanoparticles upon intramolecular metal–ligand complex formation with different metal-ions and Taylor dispersion analysis is employed to reliably characterize the dispersed particles.

Metal ion – biomolecule interactions. Part 16. C(2)-H isotopic exchange in Co(III)-coordinated imidazoles

1995 ◽  
Vol 73 (6) ◽  
pp. 772-780 ◽  
Author(s):  
Erwin Buncel ◽  
Fan Yang ◽  
Robert Y. Moir ◽  
Ikenna Onyido
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Hydrogen Exchange ◽  
Isotopic Exchange ◽  
Negative Charge ◽  
Ligand Complex ◽  
Transition State Stabilization ◽  
Anionic Species ◽  
Metal Ligand ◽  
Ligand Bond

Transition-metal-bound imidazoles are suitable models for evaluating the roles of metal ions in biomolecules having the imidazole moiety and similar heterocyclic residues as part of their structure. Such studies provide useful insights into metal–biomolecule interactions in biological systems, especially when the lability of the metal–ligand bond is substantially reduced, such that the identity of the metal–ligand complex is preserved during the course of the reaction under investigation. The present paper reports on a kinetic study of tritium exchange from the C(2) position of the imidazole moiety in the substitution-inert complex cations [Co(NH3)5[2-3H]-imidazole]3+ (1) and [Co(NH3)5-1-methyl-[2-3H]-imidazole]3+ (2). Rate–pH profiles have been determined in aqueous solution at 60 °C. Both substrates are believed to react through rate-determining attack of hydroxide ion (kM+ pathway) at C(2)-T. Dissection of the kinetic data reveals an additional pathway for 1 consequent upon deprotonation of its pyrrole-like N-H(T) to yield 3, which is then attacked by hydroxide at C(2) (kM pathway). The ratio kM+/kM = 103 that is obtained is in accord with the expected reduced reactivity of 3. Comparison of the present data with those reported for a variety of heterocyclic substrates shows that the order of reactivity, protonated [Formula: see text] metal ion coordinated [Formula: see text] neutral form of substrates, prevails. The superiority of the proton over metal ions in catalyzing isotopic hydrogen exchange is attributed to its larger ground state acidifying effect coupled with the greater transition state stabilization it affords, relative to metal ions. The exchange reaction of 3 via the kM pathway is the first example of a reactive anionic species in which the negative charge is located α to the exchanging C-H. Keywords: tritium exchange, cobalt (III)-coordinated imidazoles.

pH-static titrations for kinetic studies of metal-ligand complex formation: The case example of the reaction between Strontium(II) and DOTA

2019 ◽  
Vol 498 ◽  
pp. 119147
Author(s):  
V. Di Marco ◽  
P. Pastore ◽  
M. Tosato ◽  
A. Andrighetto ◽  
F. Borgna ◽  
...  
Keyword(s):  
Complex Formation ◽  
Kinetic Studies ◽  
Ligand Complex ◽  
Metal Ligand

Single chain polymeric nanoparticles as compartmentalised sensors for metal ions

2012 ◽  
Vol 3 (11) ◽  
pp. 3166 ◽  
Author(s):  
Martijn A. J. Gillissen ◽  
Ilja K. Voets ◽  
E. W. Meijer ◽  
Anja. R. A. Palmans
Keyword(s):  
Metal Ions ◽  
Polymeric Nanoparticles ◽  
Single Chain

scholarly journals Complexation equilibria of ambroxol hydrochloride in solution by potentiometric and conductometric methods

2018 ◽  
Vol 9 (1) ◽  
pp. 49-56
Author(s):  
Ahmed Hosny Naggar ◽  
Hammed Mohammed Al-Saidi ◽  
Othman Abd El-Moaty Farghaly ◽  
Taher Mohammed Hassan ◽  
Salma Zaidan Mohamed Bortata
Keyword(s):  
Ionic Strength ◽  
Metal Ions ◽  
Stability Constants ◽  
Formation Constants ◽  
Alkaline Media ◽  
Ligand Complex ◽  
Complex Species ◽  
The Stability ◽  
Ambroxol Hydrochloride ◽  
Metal Ligand

The formation constants of Li(I), Mg(II), Sr(II), Ca(II), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Ba(II), Pb(II), Al(III), Cr(III), Fe(III) and Th(IV) ions with ambroxol hydrochloride (AMB) were calculated using the half-n value. In presence of 0.1 M NaNO3, metal ions such as Zn(II), Cd(II), Ni(II), Cr(III), Li(I), Mg(II) and Al(III) forms three types of metal-ligand complexes (1:1, 1:2 and/or 1:3), while Sr(II) and Co(II) tend to form two types of metal complexes 1:1 and 1:2 (M:L). For ligand protonation constants, two logarithmic association constant values were calculated by the half-n method and are 10.7 and 7.6, respectively. The effect of ionic strength on stability constant of AMP, with different metal ions viz. Fe(III), Th(IV), Al(III), Cr(III) and Cu(II) was studied. Based on relationship between the ionic strength studied values and the 1st stability constants (Log K1H), we can conclude that the stability constants of the formed metal-ligand complex (1:1) were decreased as the ionic strength increased. The stoichiometry of the formed complexes in solution were determined by conductometric method and it is found to be of 1:1, 1:2 and/or 1:3 (M:L) complex species is formed in alkaline media. Also, study the species distribution diagrams of AMP for the calculated mole fraction αML and αML2 were discussed.

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