Morphology and radical reactions of Cu(II) and Co(II) sulfonated phthalocyanines covalently linked to poly(ethyleneamide)

2010 ◽  
Vol 14 (01) ◽  
pp. 69-80 ◽  
Author(s):  
Gustavo T. Ruiz ◽  
Alexander G. Lappin ◽  
Guillermo Ferraudi
Keyword(s):  
Aqueous Solutions ◽  
Redox Reactions ◽  
Radical Reactions ◽  
Stable Bundles ◽  
Carbon Bonds ◽  
Amine Groups ◽  
Covalently Linked ◽  
The Stability ◽  
Sulfonated Phthalocyanines

The tetrasulfonated Cu II( tspc )4-, tspc = 4,4′,4″,4‴-phthalocyaninetetrasulfonate, and the trisulfonated Co II( trspc )3-, trspc = n , n ′, n ″-phthalocyanine-trisulfonate and n, n′ and n″ indicate the sulfonated positions of the various isomers, were covalently linked to a polyethyleneimine, M n ~ 10000 and M w ~ 25000, backbone. A fraction of the amine groups in a strand was converted to Cu II pc (- SO 3)3(- SO 2 N <)\3- or Co II pc (- SO 3)2(- SO 2 N <)\2- pendants and the remaining were acetylated. Strands of the polymers, poly(K3CuIItspc) and poly(K2CoIItrspc) , formed spherical bundles with diameters ~1000 nm for poly(K3CuIItspc) and ~100 nm for poly(K2CoIItrspc) . The stability of the bundles is metal-dependent. Poly(K2CoIItrspc) forms the most stable bundles with respect to hydrolytic and redox reactions. ESR and optical spectroscopies as well as reactions of the pendants with pulse radiolytically generated radicals, namely e - sol , C•H2OH, (CH3)2COHC•H2 , CO 2•-, N 3• and SO 4•-, revealed a distribution of pendants between isolated and aggregated forms in a bundle. The reduction of the Cu(II) to Cu(I) in aqueous solutions of the poly(K3CuIItspc) was associated with pendants present in a mostly hydrophobic environment. Unstable phthalocyanine pendants with CoIII -carbon bonds are formed when CoIIpc(-SO3)2(-SO2N<)\2- reacted with C -centered radicals, ( CH3)2COHC•H2 and C•H2OH . The species with CoIII -carbon bonds were precursors to the formation of CoIpc(-SO3)2(-SO2N<)\3- pendants. The redox reactions of the pendants in these polymers are compared with those of K4CuIItspc and K3CoIItrspc .

Reactions of ozone and intermediate products of its decomposition with actinides, lanthanides and transition metals in aqueous solutions

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Boris G. Ershov ◽  
Bladimir P. Shilov
Keyword(s):  
Transition Metals ◽  
Aqueous Solutions ◽  
Redox Reactions ◽  
Outer Sphere ◽  
Ozone Decomposition ◽  
Decomposition Products ◽  
Coordination Spheres ◽  
Anions And Cations ◽  
The Stability ◽  
Mechanisms Of Reactions

Abstract The properties and stability of ozone in aqueous solutions of various compositions in the рН range of 0–14 were considered. The effect of anions and cations, which are involved in the redox reactions of actinides, on the stability of ozone and its reactivity has been studied. The reactions of О3 with ions of d- and f-elements were analyzed. Depending on the solution composition and рН value, the reaction can occur directly with the O3 molecule (direct mechanism) and/or with short-lived ion-radical products (•OH, HO 2 • / O 2 − • ${\text{HO}}_{2}^{{\bullet}}/{\text{O}}_{2}^{-{\bullet}}$ , H2O2/ HO 2 − ${\text{HO}}_{2}^{-}$ , O 3 − • ${\text{O}}_{3}^{-{\bullet}}$ ) formed upon ozone decomposition in water (indirect mechanism). Ions with inert coordination sphere react with О3 in the outer-sphere fashion with electron transfer. Polyvalent ions with labile coordination spheres are oxidized in acidic medium via О atom transfer, possibly, with intermediate peroxy addition (H2O2, HNO4, H2SO5, etc.). In alkaline medium, О3 is converted to the O 3 − • ${\text{O}}_{3}^{-{\bullet}}$ radical ion, which is the key oxidant for actinides. The results of studies and the mechanisms of reactions of ozone and its intermediates decomposition products with U, Np, Pu, and Am in various oxidation states and with some transition metals (Fe, Mn, Ag, Co, etc.) in aqueous solutions are presented and discussed.

On the Structure of Lead(II) Complexes in Aqueous Solutions. I. Trinuclear Clusters

1995 ◽  
Vol 60 (4) ◽  
pp. 527-536 ◽  
Author(s):  
Martin Breza ◽  
Alena Manová
Keyword(s):  
Quantum Chemistry ◽  
Aqueous Solutions ◽  
Electronic Structures ◽  
Mndo Method ◽  
Model Systems ◽  
Trinuclear Clusters ◽  
The Stability ◽  
Semiempirical Mndo

Using semiempirical MNDO method of quantum chemistry the optimal geometries and corresponding electronic structures of [Pb3(OH)n]6-n model systems as well as of their hydrated [Pb3(OH)n(H2O)8-n]6-n analogues (n = 4, 5) are investigated. The most stable trinuclear lead(II) complexes present in aqueous solutions correspond to cyclo-(μ3-OH)(μ2-OH)3Pb32+, Pb(μ-OH)2Pb(μ-OH)2Pb2+, cyclo-(μ3-OH)2(μ2-OH)3Pb3+, Pb(OH)(μ-OH)2Pb(μ-OH)Pb(OH)+ and Pb(OH)(μ-OH)2Pb(μ-OH)2Pb+ systems. The key role of OH bridges (by vanishing direct Pb-Pb bonds) on the stability of individual isomers is discussed.

scholarly journals A Raman, SERS and UV-circular dichroism spectroscopic study of N-acetyl-l-cysteine in aqueous solutions

2019 ◽  
Vol 43 (38) ◽  
pp. 15201-15212 ◽  
Author(s):  
R. A. Cobos Picot ◽  
M. Puiatti ◽  
A. Ben Altabef ◽  
R. J. G. Rubira ◽  
S. Sanchez-Cortes ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Circular Dichroism ◽  
Aqueous Solutions ◽  
Spectroscopic Study ◽  
Electronic Properties ◽  
Structural Properties ◽  
Amine Groups ◽  
Circular Dichroïsm

The aim of this work is to evaluate the vibrational and structural properties of N-acetyl-l-cysteine (NAC), and its molecular structure and electronic properties in relation to the action of thiol and amine groups at different pH.

scholarly journals Effective replacement of cetyltrimethylammonium bromide (CTAB) by mercaptoalkanoic acids on gold nanorod (AuNR) surfaces in aqueous solutions

Nanoscale ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 658-668 ◽  
Author(s):  
Rafael del Caño ◽  
Jose M. Gisbert-González ◽  
Jose González-Rodríguez ◽  
Guadalupe Sánchez-Obrero ◽  
Rafael Madueño ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Gold Nanorods ◽  
Ligand Exchange ◽  
Cetyltrimethylammonium Bromide ◽  
Gold Nanorod ◽  
Experimental Conditions ◽  
Seed Mediated ◽  
The Stability

The highly packed cetyltrimethylammonium bromide bilayer on the surface of gold nanorods synthesized by the seed-mediated procedure hampers the complete ligand exchange under experimental conditions that preserves the stability of the dispersions.

Directionality and the Role of Polarization in Electric Field Effects on Radical Stability

2017 ◽  
Vol 70 (4) ◽  
pp. 367 ◽  
Author(s):  
Ganna Gryn'ova ◽  
Michelle L. Coote
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Radical Reactions ◽  
Electric Field Effects ◽  
Dissociation Energies ◽  
Barrier Heights ◽  
Diol Dehydratase ◽  
Group A ◽  
Activity Of Enzymes ◽  
The Stability

Accurate quantum-chemical calculations are used to analyze the effects of charges on the kinetics and thermodynamics of radical reactions, with specific attention given to the origin and directionality of the effects. Conventionally, large effects of the charges are expected to occur in systems with pronounced charge-separated resonance contributors. The nature (stabilization or destabilization) and magnitude of these effects thus depend on the orientation of the interacting multipoles. However, we show that a significant component of the stabilizing effects of the external electric field is largely independent of the orientation of external electric field (e.g. a charged functional group, a point charge, or an electrode) and occurs even in the absence of any pre-existing charge separation. This effect arises from polarization of the electron density of the molecule induced by the electric field. This polarization effect is greater for highly delocalized species such as resonance-stabilized radicals and transition states of radical reactions. We show that this effect on the stability of such species is preserved in chemical reaction energies, leading to lower bond-dissociation energies and barrier heights. Finally, our simplified modelling of the diol dehydratase-catalyzed 1,2-hydroxyl shift indicates that such stabilizing polarization is likely to contribute to the catalytic activity of enzymes.

scholarly journals Investigations of ternary complexes of Co(II) and Ni(II) with thiodiacetate anion and 1,10-phenanthroline or 2,2’-bipyridine in aqueous solutions

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Dariusz Wyrzykowski ◽  
Joanna Pranczk ◽  
Dagmara Jacewicz ◽  
Aleksandra Tesmar ◽  
Bogusław Pilarski ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Substitution Reactions ◽  
Experimental Conditions ◽  
Kinetic Measurements ◽  
Hydroxo Complexes ◽  
Binary Complexes ◽  
Vis Spectroscopy ◽  
Potentiometric Titration Method ◽  
The Stability ◽  
Ph Range

AbstractA potentiometric titration method (PT) and a stopped-flow kinetic technique monitored by a UV−Vis spectroscopy have been used to characterize the stability of series of Co(II)- and Ni(II)-thiodiacetato complexes, M(TDA), in the presence of 1,10-phenanthroline (phen) or 2,2’-bipyridine (bipy) in aqueous solutions. The stability constants of the binary (1:1), ternary (1:1:1) as well as the resulting hydroxo complexes were evaluated and compared to the corresponding oxydiacetate complexes. Based on the species distribution as a function of pH the relative predominance of the species in the system over a pH range was discussed. Furthermore, the kinetic measurements of the substitution reactions of the aqua ligands to phen or bipy in the coordination sphere of the binary complexes M(TDA) were performed in the 288–303 K temperature range, at a constant concentration of phen or bipy and at seven different concentrations of the binary complexes (0.2–0.5 mM). The kinetic stability of the M(TDA) complexes was discussed in relation to the experimental conditions and the kind of the auxiliary ligands (phen/bipy). Moreover, the influence of the type of primary ligand (thiodiacetate/oxydiacetate) on the substitution rate of the auxiliary ligands was also compared.

Addition of Aliphatic and Aromatic Amines to Catechol in Aqueous Solution Under Oxidizing Conditions

1989 ◽  
Vol 42 (3) ◽  
pp. 365 ◽  
Author(s):  
MK Manthey ◽  
SG Pyne ◽  
RJW Truscott
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Aromatic Amines ◽  
Aliphatic Amines ◽  
Substitution Pattern ◽  
Vinylogous Amides ◽  
The Stability

The oxidation of catechol in the presence of two aliphatic and aromatic amines has been investigated. In aqueous solutions of pH 7.0 and 11.7, the substitution pattern of the adduct was dependent on the type of amine used. Aromatic amines produced 4,5-disubstituted o-quinones, whereas aliphatic amines gave either 2,4,5-trisubstituted or 2,4-disubstituted o-quinone adducts. A rationale based upon the stability of vinylogous amides is presented to account for the observed substitution pattern.

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