CEAC-Coordination and Equilibria in Analytical Chemistry

IULIANO MAURO

Room 2N-03; phone +39-081-674376 Email: miuliano@unina.it ;

https://www.docenti.unina.it/mauro.iuliano

https://orcid.org/000-0001-7367-651X

DE TOMMASO GAETANO

Room 2N-11; phone +39-081-674385 Email: gaetano.detommaso@unina.it;

https://www.docenti.unina.it/gaetano.detommaso

http://orcid.org/0000-0001-6044-2255

FRANCESCO SALVATORE

Room 2N14; phone +39-081-674983 Email frsalvat@unina.it;

https://www.docenti.unina.it/francesco.salvatore2

https://orcid.org/0000-0003-0212-1271

CARLA MANFREDI

Room 2N06; phone +39-081-674379 Email carla.manfredi@unina.it;

https://www.docenti.unina.it/carla.manfredi

https://orcid.org/0000-0002-4039-8995

Research:

Coordination properties of molecules of biological interest

Kinetic and adsorption of toxic species on to solid phases

Equilibrium Analysis and Development of Analytical methods

 

Coordination properties of molecules of biological interest

The development of radioisotopes of inorganic elements has gained much interest in recent years for diagnostic and therapeutic application in nuclear medicine. Biologically active molecules (as aminoacids, gluthatione, ecc.) and oligopeptides are employed for complexing the radiometal in a biologically stable environment (as 68Ga(III) and 188Re(I)). Aim of the present work has been the interaction between fac-[Re(H2O)3(CO)3]+ (Me+) and Ga3+ ions with a bis-histidine oligopeptide (L) in aqueous solutions, by potenziometry, spectrofluorimetry, FT−IR and 1H-NMR spectroscopy and circular dichroism. By processing the experimental data, it will be possible to obtain the complexation constants. As part of this research, the complexing properties of molecules of biological interest towards the beryllium (II) cation will be studied with potentiometric and spectroscopic methods. Furthermore, the project intends to investigate the adsorption of the Be2+ with surfaces present in biological systems, such as bacteria membranes of Bacillus subtilis and Bacillus acidocaldarius

 

Kinetic and adsorption of toxic species on to solid phases

The use of biodegradable complexing agents with high sequestering capacity towards toxic metals is a sustainable technique that modifies little of the ecosystem (soil washing). (S,S) Ethylenediamine-N,N'-disuccinic acid (EDDS) represents a valid candidate for such use, due to its biodegradability. In the present project we intend to study the sequestering capacity of the EDDS ligand on the volcanic tuff of zeolitic matrix (neapolitan yellow tuff variety), very common in the phlegrean area, contaminated by heavy metals. EDDS complexation reactions towards some transition metals (such as Pb(II), Cd(II), etc.) and some lanthanides (La(III), Gd(III), etc.) will be studied. The stoichiometric of the metal-binding species in solution will be validated through spectroscopic measurements (UV-VIS, CD-UV and 1H-NMR). Finally, the efficiency of the removal of heavy metals from a sample of contaminated tuff will be studied at 25º C, depending on the pH and the ligand concentration.

 

Selected publications:

  • V. Romanucci, C. Agarwal, R. Agarwal, C. Pannecouque, M. Iuliano, G. De Tommaso, T. Caruso, G. Di Fabio and A. Zarrelli, "Silibinin phosphodiester glyco-conjugates: synthesis, redox behaviour and biological investigations", Bioorg Chem. (2018) 77,349-359.
  • G. De Tommaso, V. Celentano, G. Malgieri, R. Fattorusso, A. Romanelli, L. D. D'Andrea, M. Iuliano, C. Isernia, "fac−[Re(H2O)3(CO)3]+ complexed with Histidine and Imidazole in Aqueous Solution: Speciation, Affinity and Binding Features", Chemistry Select (2016), 1, 3739–3744
  • M. Iuliano and G. De Tommaso, "Interaction of iron(III) with 2-hydroxybenzohydroxamic acid in aqueous solutions", J. Chem. Eng. Data (2010), 55(1), 400-404.
  • G. De Tommaso and M. Iuliano, "Acid–base properties of the surface of hydrous ferric phosphate in aqueous solutions", J. Chem. Eng. Data (2012), 57(1), 52–59.
  • M. Iuliano, L. Ciavatta and G. De Tommaso, "Protolytic behavior of hydroxylated Pyrex glass surfaces in NaCl media", J.Colloid Interface Sci. (2007), 310, 402-410.
  • M. Iuliano, G. De Tommaso, L. Ciavatta and R. Ragone, "Homocysteine disulphides and vascular disease", Disease Markers (2009), 27(2), 55-61.

 

Coordination properties of molecules of biological interest

The development of radioisotopes of inorganic elements has gained much interest in recent years for diagnostic and therapeutic application in nuclear medicine. Biologically active molecules (as aminoacids, gluthatione, ecc.) and oligopeptides are employed for complexing the radiometal in a biologically stable environment (as 68Ga(III) and 188Re(I)). Aim of the present work has been the interaction between fac-[Re(H2O)3(CO)3]+ (Me+) and Ga3+ ions with a bis-histidine oligopeptide (L) in aqueous solutions, by potenziometry, spectrofluorimetry, FT−IR and 1H-NMR spectroscopy and circular dichroism. By processing the experimental data, it will be possible to obtain the complexation constants. As part of this research, the complexing properties of molecules of biological interest towards the beryllium (II) cation will be studied with potentiometric and spectroscopic methods. Furthermore, the project intends to investigate the adsorption of the Be2+ with surfaces present in biological systems, such as bacteria membranes of Bacillus subtilis and Bacillus acidocaldarius

 

 

Equilibrium Analysis and Development of Analytical methods

Natural systems are too complex to be studied directly. In water, chemical interactions mainly take place through acid-base, redox, precipitation or complexation reactions. The products may be species capable of individual existence. If so, they can be characterized by means of the classical analytical methods, which generally imply one or more separation steps prior to the analysis. Alternatively, the products formed may be complexes, i.e. specie sin a dynamic, often reversible chemical equilibrium, which obey the law of mass action and thus cannot be separated. To investigate a chemical equilibrium implies the determination of the composition of the species (complexes) formed by the reaction of one or more coordinating reagents with one or more ligands, as well as their formation constants. Speciation of the solution is the qualitative and quantitative description in terms of the complexes formed and their concentrations. The Speciation of a metal ion in a solution thus not only provides its total analytical concentration, but a detailed knowledge of its partition between all the ligands in solution. This represents a fundamental requirement both for the comprehension of the chemical and the physical behavior as well as for the interpretation of the properties of a system investigated including the toxicity versus living organisms, the affinity of the ligands for other metals present in solution, and the therapeutic efficiency. It further allows for understanding the role of the complexes in the genesis of minerals, for evaluating the possibility that toxic metals be transported in the biosphere. The data necessary for the speciation in systems characterized by chemical equilibrium, are only accessible by means of the criteria of Equilibrium Analysis, which is based on the measurements of one or more chemical-physical properties (electrode potential, absorbance of electromagnetic radiation, solubility of solid phases, distribution between solvents, etc.) without perturbing the state of equilibrium. The interpretation of the experimental data (potentiometric, polarographic and spectrophotometric data) is done by using graphic methods and numerical ones (as LETAGROP and HYPERQUAD). The main research lines that are developed, following the guidelines exposed above, are described as follows: a) Interaction's studies of metals ions with biologically active ligands (as nicotine and resveratrol) in aqueous solutions. Lanthanide complexes with ligands such as 1,4,7,10-Tetraazacyclododecane-1,4,7,10- tetraacetic acid (DOTA) and its derivatives (systems used as contrast agents for Magnetic Resonance Imaging) are also studied. b) Studies on [1,2,4]triazolo[3,2-c][1,2,4]triazole derivatives, class of compounds which shows many relevant applications as building blocks of active molecules in many fields of advanced materials as well as conducting polymers, organic field-effect transistors, Dye-sensitized Solar Cells (DSSC), nonlinear optically active and liquid crystalline compounds, high energy compounds. c) Characterization of carbon nanostructured materials obtained from oxidation of carbon black, having uniform dimensions and a good grade of dispersion in water. The study consists on to define the acid-base properties and the metal ions adsorption on the surface of the carbon materials. d) Development of Analytical methods for the identification and quantification of natural and synthetic substances mainly via hyphenated (GC/MS and LC/MS) and electrochemical (mainly voltammetric) techniques.

 

Selected publications:

  • C. Manfredi, S. Vero, E. Vasca, D. Perrotta, M. Trifuoggi, I. Sorrentino& D. Ferri "On the Interaction Between Nicotine and Metal(II) Ions in Aqueous Solutions" . J Solution Chem "(2016) 45: 971.
  • C. Manfredi, M. Trifuoggi, A.Amoresano, E.Vasca, C.Pepe, S.Volino, M.Annetta "On Trans-Resveratrol in Aqueous Solutions" J Solution Chem (2017) 46: 2214.
  • M.Trifuoggi, E.Vasca, C.Manfredi "Rare Earth Elements Equilibria in Aqueous Media" in Rare Earth Elements in Human and Environmental Health: Chapter 11 G.Pagano (Ed.) Pan Stanford Publishing Pte. Ltd.(2016)
  • R. Centore, C. Manfredi, S. Fusco, C. Maglione, A. Carella, A. Capobianco, A. Peluso, D. Colonna, A. Di Carlo, "Proton induced tautomeric switching in N-rich aromatics with tunable acid-base character" J. Mol. Struc, (2015) 1093, 119–124.
  • R. Centore, C. Manfredi, A. Capobianco, S. Volino, M. V. Ferrara, A. Carella, S. Fusco, and A. Peluso "Solid State Separation and Isolation of Tautomers of Fused-Ring Triazolotriazoles" (2017) J. Org. Chem. 82 (10), 5155-5161
  • V. Gargiulo, M. Alfè, L. Lisi, C. Manfredi, S. Volino, F. Natale: "Colloidal Carbon-Based Nanoparticles as Heavy Metal Adsorbent in Aqueous Solution: Cadmium Removal as a CaseStudy". Water Air Soil Pollut (2017) 228:192
  • Maria Michela Salvatore, Marina Della Greca, Rosario Nicoletti, Francesco Salvatore , Francesco Vinale, Daniele Naviglio, Anna Andolfi ‘Talarodiolide, a New 12-Membered Macrodiolide, and GC/MS Investigation of Culture Filtrate and Mycelial Extracts of Talaromyces pinophilus', Molecules (2018), 23(4), 950.
  • Marco Guida, Maria Michela Salvatore and Francesco Salvatore, ‘A Strategy for GC/MS Quantification of Polar Compounds via their Silylated Surrogates: Silylation and Quantification of Biological Amino Acids' Journal of Analytical and Bioanalytical Techniques (2015), 6, 5.
  • Marco Guida, Maria Michela Salvatore and Francesco Salvatore, ‘Riboflavin (Vitamin B2) Assay by Adsorptive Cathodic Stripping Voltammetry (Adcsv) at the Hanging Mercury Drop Electrode (HMDE)' Biochemistry & Physiology (2015) 4,4
  • Francesco Salvatore, Maria Michela Salvatore, ‘An Attractive Way of Developing the Concept of Systematic Titration Error of Visual Acid-Base Titrations (on the Basis of Logarithmic Acid-BaseDiagrams)' World Journal of Chemical Education (2014), 2, 20.