Complexes of Cu(II) Ions and Noncovalent Interactions in Systems with L-Aspartic Acid and Cytidine-5'-Monophosphate

Interactions between aspartic acid (Asp) and cytidine-5-monophosphate (CMP) in metal-free systems as well as the coordination of Cu(II) ions with the above ligands were studied. The composition and overall stability constants of the species formed in those systems were determined by the potentiometric method, and the interaction centres in the ligands were identified by the spectral methods UV-Vis, EPR, NMR, and IR. In metal-free systems, the formation of adducts, in which each ligand has both positive and negative reaction centres, was established. The main reaction centres in Asp are the oxygen atoms of carboxyl groups and the nitrogen atom of the amine group, while the main reaction centre in CMP at low pH is the N(3) atom. With increasing pH, the efficiency of the phosphate group of the nucleotide in the interactions significantly increases, and the efficiency of carboxyl groups in Asp decreases. The noncovalent reaction centres in the ligands are simultaneously the potential sites of metal-ion coordination. The mode of coordination in the complexes formed in the ternary systems was established. The sites of coordination depend clearly on the solution pH. In the molecular complexesML⋯L, metallation involves the oxygen atoms of the carboxyl groups of the amino acid, while the protonated nucleotide is in the outer coordination sphere and interacts noncovalently with the anchoringCuHx(Asp) species. The influence of the metal ions on the weak interactions between the biomolecules was established.

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Structure of the complexes of ethylenediphosphinetetraacetic acid in solution

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19850445 ◽

1985 ◽

Vol 50 (2) ◽

pp. 445-453 ◽

Cited By ~ 2

Author(s):

Jana Podlahová ◽

Josef Šilha ◽

Jaroslav Podlaha

Keyword(s):

Metal Ion ◽

Carboxyl Groups ◽

Complex Solution ◽

Square Planar ◽

Weak Complexes ◽

Carboxylic Groups ◽

Uv Visible ◽

The Stability ◽

Tetrahedral Complexes ◽

Free Carboxyl

Ethylenediphosphinetetraacetic acid is bonded to metal ions in aqueous solutions in four ways, depending on the type of metal ion: 1) through an ionic bond of the carboxylic groups to form weak complexes with a metal:ligand ratio of 1 : 1 (Ca(II), Mn(II), Zn(II), Pb(II), La(III)); 2) through type 1) bond with contributions from weak interaction with the phosphorus (Cd(II)); 3) through coordination of the ligand as a monodentate P-donor with the free carboxyl groups with formation of 2 : 1 and 1 : 1 complexes (Cu(I), Ag(I)); 4) through formation of square planar or, for Hg(II), tetrahedral complexes with a ratio of 1 : 2 with the ligand as a bidentate PP-donor with the free carboxyl groups (Fe(II), Co(II), Ni(II), Pd(II), Pt(II)). On acidification of the complex solution, the first two protons are bonded to the carboxyl groups. The behaviour during further protonation depends on the type of complex: in complexes of types 1) and 2) phosphorus is protonated and the complex dissociates; in complexes of types 3) and 4) the free carboxyl groups are protonated and the phosphorus-metal bond remains intact. The results are based on correlation of the stability constants, UV-visible, infrared, 1H and 31P NMR spectra and magnetic susceptibilities of the complexes in aqueous solution.

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Zn(II) and Ag(I) complexes of N-allythioamides of pyrimidinyl (cyclohexenyl) carboxylic acids and products their proton- and iodocyclization

Ukrainian Chemistry Journal ◽

10.33609/0041-6045.85.3.2019.3-19 ◽

2019 ◽

Vol 85 (3) ◽

pp. 3-19

Author(s):

Polina Borovyk ◽

Mariia Litvinchuk ◽

Anton Bentya ◽

Svitlana Orysyk ◽

Yurii Zborovskiy ◽

...

Keyword(s):

Carboxylic Acids ◽

Metal Ion ◽

Polymer Chains ◽

Hydroxyl Group ◽

Hydroxyl Groups ◽

Polymer Complexes ◽

Vis Spectroscopy ◽

Polynuclear Coordination Compounds ◽

Complexation Reactions ◽

Oxygen Atoms

The possibility of using N-allylcarbothioamide derivatives as well as products of their iodine- and proton-initiated electrophilic heterocyclizations as chelating agents in complexation reactions with Zn(II) and Ag(I) ions is shown. Processing of the obtained experimental data showed that N-allythioamides of pyrimidinyl (cyclohexenyl) carboxylic acids H2L1 – H2L3 and their proton- and iodo-cyclization products HL4, HL5 containing four nucleophilic reaction centers (two oxygen atoms of the carbonyl and hydroxyl groups and N-, S-carbothioamide groups or N-atoms of the dihydrothiazole moiety) are polydentate ligands capable of coordinating with metal ions to form stable six-membered chelate metallocycles. A series of new chelating mono-, bi- and polynuclear complexes Zn(II) and Ag (I) of the composition [Zn2L1,32]n, [Zn2(HL1-3)2(CH3COO)2], [Ag2(HL1,3)2]n, [Zn(HL1-3)2], [Ag(H2L3)2NO3], [Zn(HL4,5)2], K[Ag(HL4,5)2] were synthesized and isolated in solid state. Their molecular structure was established by methods of elemental chemical analysis, NMR 1H, IR and UV-Vis spectroscopy. At a ratio of M:L 1:2, complexes were isolated in which two ligand molecules H2L1 − H2L3 are coordinated to the metal ion by the sulfur atoms of the carbothioamide group and the oxygen of the mono-deprotonated hydroxyl group. It was established that the products of the proton-/iodocyclization HL4, HL5 in the complex formation pass into the thione tautomeric form with coordination through the oxygen atoms of the deprotonated hydroxyl group and nitrogen atoms of the dihydrothiazole heterocycle. At M:L 1:1, binuclear or polynuclear coordination compounds are formed. It was shown that polymerisation in complexes [Zn2L1,32]n and [Ag2(HL1,3)2]n is due to the formation of Zn−(O2SN)−Zn and Ag−O−Ag polymer chains. Investigation of the solubility of the resulting complexes showed that the polymer complexes are weakly soluble or insoluble in DMSO, DMF, while the mononuclear are soluble in methanol, as well as in water.

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Chelation and Metal-Ion Complex Formation of Chitosan Treated Cotton

Majalah ilmiah Pengkajian Industri ◽

10.29122/mipi.v8i3.3652 ◽

2019 ◽

Vol 8 (3) ◽

pp. 93-100 ◽

Cited By ~ 1

Author(s):

Sudirman Habibie

Keyword(s):

Cotton Fabric ◽

Metal Ion ◽

Chelating Agents ◽

Transition Metal Ions ◽

Cotton Fabrics ◽

Carboxyl Groups ◽

Polycarboxylic Acid ◽

Salt Solutions ◽

Polycarboxylic Acids ◽

Zinc Salts

Chitin dan chitosan adalah bahan â€œchelateâ€ yang sangat kuat untuk ion transisi logam terutama tembaga, nikel dan merkuri, dan sifat-sifat ini yang akan intensif di bahas. Pada studi ini kain kapas (cotton) dikerjakan dengan larutan chitosan-asam polikarboksilat untuk memperoleh kain kapas-chitosan yang mengandung gugus group karboksilat (-COOH) dan gugus amina (-NH2) fungsional. Penggunaan asam polykarboksilat (asam sitrat dan maleik) pada pelarutan chitosan menghasilkan group karboksil 0,5 meqs/g pada kain yang dicelup dengan larutan chitosan asam karboksilat. Kemudian kain kapas yang telah mengandung gugus karboksilat dan gugus amina ini dicelupkan pada larutan garam logam (garam tembaga dan seng). Terbukti bahwa larutan garam tembaga (copper) memberikan warna biru pada kain, hal ini mengindikasikan telah terjadi reaksi kompleks atau â€œChelateâ€. Implikasi dari hasil ini maka diperkirakan kandungan group karboksil dan amina ini akan mempengaruhi pada pencelupan kain, namun hal ini tidak diuji.Kata kunci : Chitosan, Kain Kapas, Chelate, Asam asetat, Asam citrate, Asam maleik, Tembaga sulphate, Tembaga acetate.AbstractChitin and chitosan are powerfull chelating agents for transition metal ions, particularly copper, nickel and mercury, and these properties have been extensively reviewed. In this study, cotton fabric has been treated with chitosan- polycarboxylic acid solution to form chitosan treated cotton fabric containing carboxyl (-COOH) and amine (-NH2) functional groups. The use of polycarboxylic acids (citric and maleic acids) to dissolve chitosan has given carboxyl groups 0.5 meqs/g into chitosan treated cotton fabrics. Instead, the complexing of the treated cotton samples with copper and zinc salts was examined. The copper salt solutions gave blue fabrics confirming easily that complexing or chelation had occurred. There are implications for dyeing cotton making use of these groups but this was not investigated.Keyword :Â Chitosan, Cotton fabric, Chelation, Acetic acid, Citric acid, Maleic acid, Copper (II) sulphate, Copper (II) acetate.

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Proton NMR studies of synthetic peptide analogs of calcium-binding site III of rabbit skeletal troponin C: Effect on the lanthanum affinity of the interchange of aspartic acid and asparagine residues at the metal ion coordinating positions

Biochemistry ◽

10.1021/bi00411a043 ◽

1988 ◽

Vol 27 (11) ◽

pp. 4198-4206 ◽

Cited By ~ 45

Author(s):

Brian J. Marsden ◽

Robert S. Hodges ◽

Brian D. Sykes

Keyword(s):

Binding Site ◽

Aspartic Acid ◽

Calcium Binding ◽

Synthetic Peptide ◽

Metal Ion ◽

Proton Nmr ◽

Troponin C ◽

Nmr Studies ◽

Calcium Binding Site ◽

Peptide Analogs

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A study of chromium-exchanged zeolites as potential catalysts for thermolysis of water

Canadian Journal of Chemistry ◽

10.1139/v86-228 ◽

1986 ◽

Vol 64 (7) ◽

pp. 1332-1339 ◽

Cited By ~ 2

Author(s):

K. M. Miedzinska ◽

B. R. Hollebone

Keyword(s):

Low Temperatures ◽

Metal Ion ◽

Redox Cycle ◽

Zeolite 13X ◽

Irreversible Reduction ◽

Very High ◽

Oxygen Atoms

Evidence was found that the Cr(III)/Cr(II) redox cycle previously described to occur upon dehydration and rehydration of exchanged zeolite 13X, does not occur reversibly. Data suggest dimerization of the metal ion at high levels of exchange. The bridging provideu by the oxygen atoms of the lattice probably stabilize these dimers and lead to initial but irreversible reduction at very low temperatures. Evidence also indicates irreversible formation of new lattices at very high dehydration temperatures.

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Inositol derived crown ethers: effect of auxiliary protecting groups and the relative orientation of crown ether oxygen atoms on their metal ion binding ability

Tetrahedron ◽

10.1016/j.tet.2007.12.034 ◽

2008 ◽

Vol 64 (9) ◽

pp. 2160-2171 ◽

Cited By ~ 13

Author(s):

Shailesh S. Dixit ◽

Mysore S. Shashidhar

Keyword(s):

Crown Ether ◽

Crown Ethers ◽

Metal Ion ◽

Relative Orientation ◽

Protecting Groups ◽

Ion Binding ◽

Metal Ion Binding ◽

Binding Ability ◽

Ether Oxygen ◽

Oxygen Atoms

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Thermodynamic Stability Areas of Polyvanadates of Alkaline Earth Metals

Journal of Chemistry ◽

10.1155/2019/7091781 ◽

2019 ◽

Vol 2019 ◽

pp. 1-6 ◽

Cited By ~ 1

Author(s):

Igor Povar ◽

Inga Zinicovscaia ◽

Oxana Spinu ◽

Boris Pintilie

Keyword(s):

Thermodynamic Stability ◽

Metal Ion ◽

Alkaline Earth ◽

Heterogeneous Systems ◽

Earth Metal ◽

Thermodynamic Characteristics ◽

Alkaline Earth Metals ◽

Alkaline Earth Metal ◽

Solution Ph ◽

Alkaline Earth Element

A thermodynamic method of the global Gibbs energy variation calculation for describing heterogeneous equilibria of transformations of calcium, strontium, and barium polyvanadates, that occur in systems MeO-V2O5-H2O, where Me is the alkaline earth element, has been developed and used. Its quintessence consists in the thermodynamic analysis of the real conditions of various processes on the basis of their total thermodynamic characteristics. On the basis of the selected thermodynamic data for involved species, the thermodynamic stability areas of solid polyvanadates towards the solution pH and vanadium and alkaline earth metal ion concentrations in heterogeneous mixtures have been established, taking into account the complex formation reactions in multicomponent heterogeneous systems. The existing experimental data confirm the results on the thermodynamic stability of polyvanadates obtained in this paper.

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Investigation of ORR Performances on Graphene/Phthalocyanine Nanocomposite in Neutral Medium

Microscopy and Microanalysis ◽

10.1017/s1431927619000643 ◽

2019 ◽

Vol 25 (6) ◽

pp. 1416-1421 ◽

Cited By ~ 5

Author(s):

Moumita Mukherjee ◽

Madhupriya Samanta ◽

Gour P. Das ◽

Kalyan K. Chattopadhyay

Keyword(s):

Metal Ion ◽

Low Cost ◽

Rotating Disk ◽

Reduction Reaction ◽

Rotating Disk Electrode ◽

Zinc Phthalocyanine ◽

Neutral Medium ◽

Neutral Solution ◽

Solution Ph ◽

Onset Potential

AbstractThe drive to replace scarce and expensive Pt-based electrocatalysts for oxygen reduction reaction (ORR) has led to the development of a group of electrocatalysts composed of transition-metal ion centers coordinated with four nitrogen groups (M-N4). Among these, metal phthalocyanines (MPcs), due to low cost of preparation, highly conjugated structure as well as high thermal and chemical stability, have received a great interest. The catalytic activity of MPcs can be improved by employing conducting supports. Here, in this report, we have solvothermally synthesized graphene-supported zinc phthalocyanine nanostructures, and their ORR kinetics and mechanism have been investigated in neutral solution (pH = 7) by using the rotating disk electrode technique. The as-synthesized nanocomposite followed a 4e− reduction pathway. The onset potential (−0.04 V versus Ag/AgCl) found in this work can be comparable with other state-of-the-art material, demonstrating good performance in neutral solution. The fascinating performance leads the nanocomposite material toward future energy applications.

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