Andrea Melchior

University of Udine | UNIUD · Polytechnic Department of Engineering and Architecture

Persistent pharmaceutical contaminants, such as Platinum cytostatics, commonly used in cancer therapy, have been detected in water bodies at low concentrations. Electrochemical, photochemical and biological treatments for the removal and degradation of these contaminants are expensive and sometimes ineffective. Sorption methods are a viable and mor...

The room temperature ionic liquid trihexyl(tetradecyl)phosphonium decanoate ([P66614][Dec]) was employed in the liquid-liquid extraction of Co(II) from hydrochloric acid solutions in the presence of Ni(II). The extraction performance in liquid-liquid separations showed a strong dependence on the acid content of the feed aqueous solution. The best p...

The understanding of the thermodynamic stability and speciation of metal complexes in solution requires access to their enthalpy and entropy of formation. In this work, we specifically focus our investigation on the complexation process of silver(I) ion in acetonitrile (AN) with substituted mono pyridines and cyclic monoamines. The aim of this stud...

A chiral Yb( iii ) complex bearing a conjugated chromophoric ligand exhibits potential as NIR-to-NIR chiroptical probe for biological purposes.

The complexes [Eu(bpcd)(tta)], [Eu(bpcd)(Coum)], and [Tb(bpcd)(Coum)] [tta = 2-thenoyltrifluoroacetyl-acetonate, Coum = 3-acetyl-4-hydroxy-coumarin, and bpcd = N,N'-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane-N,N'-diacetate] have been synthesized and characterized from photophysical and thermodynamic points of view. The optical and chiroptica...

To efficiently remove trace Pt-based cytostatic drugs (Pt-CDs) from aqueous environments, a comparative investigation was conducted on the adsorption behavior of three commercial adsorbents including cysteine-functionalized silica gel (Si-Cys), 3-(diethylenetriamino) propyl-functionalized silica gel (Si-DETA) and open-celled cellulose MetalZorb® sp...

Despite the globally increasing use of platinum-based cytostatic drugs in the treatment of several types of cancer, only limited attention has been paid to developing a treatment for contaminated liquid samples originating from hospitals, laboratories and manufacturing facilities before and after their administration. In this work, we assess the ef...

In this contribution, two couples of cationic enantiomeric complexes [(R,R)-[LnL]Cl and (S,S)-[LnL]Cl, with Ln = Sm and Eu and L = N, N’-bis(2-pyridylmethyl)- 1,2-(R,R or S,S)-cyclohexanediamine functionalized at sp3 N...

In this work, we investigated from a theoretical point of view the dynamics of the energy transfer process from the ligand to Eu(III) ion for 12 isomeric species originating from six different complexes differing by nature of the ligand and the total charge. The cationic complexes present the general formula [Eu(L)(H2O)2]+ (where L = bpcd2- = N,N'-...

The widely used anti-inflammatory diclofenac (DCF) is one of the pharmaceutical drugs most frequently detected in the environment as it is not fully degraded by conventional water treatment plants. Carbon-based adsorbent nanomaterials are attractive for the treatment of wastewater contaminated by pharmaceuticals, due to their high affinity for orga...

Access to the enthalpy and entropy of the formation of metal complexes in solution is essential for understanding the factors determining their thermodynamic stability and speciation. As a case study, in this report we systematically examine the complexation of silver(I) in acetonitrile (AN) with the following monoamines: n-propylamine (n-pr), n-bu...

The application of synthetic Fe-chelates stands for the most established agronomical practice to alleviate lime-induced chlorosis, which still constitutes a major agronomic problem. However, the percolation through the soil profile due to the negative charge of the most deployed molecules results in agronomical and environmental problems. H2bpcd/Fe...

The chiral cationic complex [Ru(η¹‐OAc)(CO)((R,R)‐Skewphos)(phen)]OAc (2R), isolated from reaction of [Ru(η¹‐OAc)(η²‐OAc)(R,R)‐Skewphos)(CO)] (1R) with phen, reacts with NaOPiv and KSAc affording [RuX(CO)((R,R)‐Skewphos)(phen)]Y (X=Y=OPiv 3R; X=SAc, Y=OAc 4R). The corresponding enantiomers 2S‐4S have been obtained from 1S containing (S,S)‐Skewphos....

The uncontrolled release of pharmaceutical drugs into the environment raised serious concerns in the last decades as they can potentially exert adverse effects on living organisms even at the low concentrations at which they are typically found. Among them, platinum based cytostatic drugs (Pt CDs) are among the most used drugs in cancer treatments...

The results of a potentiometric and calorimetric study on the complexation of silver(I) with neutral N-donors 1,2-diaminoethane (EN), 1,3-diaminopropane (DAP), 1,4,7-triazaheptane (DIEN), 1,5,9-triazanonane (DPT) and 1,4,7,10-tetraazadecane (TRIEN) in acetonitrile (AN) are reported. The overall enthalpy terms associated with the complex formation a...

The good chelating properties of hydroxypyrone (HPOs) derivatives towards oxidovanadium(IV) cation, VIVO2+, constitute the precondition in the development of new insulin-mimetic and anticancer compounds. In the present work, we examined the oxidovanadium(IV) complex formation equilibria of two kojic acid (KA) derivatives, L4 and L9, structurally ch...

In this minireview, we give an overview on the use of the chiral molecule trans‐1,2‐diaminocyclohexane (DACH) in several fields of application. This chiral backbone is present in a variety of metal complexes which are employed in (enantioselective) catalysis, chiral discrimination, molecular recognition and supramolecular chemistry. Metal extractio...

Phenanthriplatin (PtPPH) is a monovalent platinum(II)-based complex with a large cytotoxicity against cancer cells. Although the aqua-activated drug has been assumed to be the precursor for DNA damage, it is still under debate whether the way in which that metallodrug attacks to DNA is dominated by a direct binding to a guanine base or rather by an...

Molecular dynamics (MD) simulations and X-ray absorption spectroscopy (XAS) have been combined to study the coordination of the Co²⁺ and Ni²⁺ ions in ionic liquids (ILs) based on the bis(trifluoromethylsulfonyl)imide ([Tf2N]⁻) anion and having different organic cations, namely, 1-butyl-3-methylimidazolium ([C4mim]⁺), 1,8-bis(3-methylimidazolium-1-y...

A neutral Eu(III) complex containing the S,S enantiomer of isoQC3A3- ligand (isoQC3A3- = N-isoquinolyl-N,N’,N’-trans-l,2-cyclohexylenediaminetriacetate) was synthesized and characterized. The complex was spectroscopically investigated and the results compared with those obtained...

X-ray absorption spectroscopy (XAS) has been employed to study the coordination of the Ag+ ion in aqueous solution. The conjunction of extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) data analysis provided results suggesting the preference for a first shell linear coordination with a mean Ag-O bond...

The cationic enantiopure (R,R) and luminescent Eu(III) complex [Eu(bisoQcd)(H2O)2] OTf (with bisoQcd = N,N'-bis(2-isoquinolinmethyl)-trans-1,2-diaminocyclohexane N,N'-diacetate and OTf = triflate) was synthesized and characterized. At physiological pH, the 1:1 [Eu(bisoQcd)(H2O)2]+ species, possessing two water molecules in the inner coordination sp...

The ability of carbon-based nanomaterials (CNM) to interact with a variety of pharmaceutical drugs can be exploited in many applications. In particular, they have been studied both as carriers for in vivo drug delivery and as sorbents for the treatment of water polluted by pharmaceuticals. In recent years, the large number of experimental studies w...

We report in this paper an unusual β-cyclodextrin mediated-aluminum (III) ion sensing based on augmented quenching of fluorescence. The fluorescent sensing of metal ions by a new ligand prepared (L = 4-[{4-(1H-imidazol-1-yl)phenyl]imino}methyl]piperazine-1-carboxaldehyde) has been investigated as well as the effect of the supramolecular complex for...

Each enantiopure europium(III) and samarium(III) nitrate and triflate complex of the ligand L, with L = N,N'-bis(2-pyridylmethylidene)-1,2-(R,R + S,S)-cyclohexanediamine ([LnL(tta)2]·NO3 and [LnL(tta)2(H2O)]·CF3SO3, where tta = 2-thenoyltrifluoroacetylacetonate) has been synthesized and characterized from a spectroscopic point of view, using a chir...

The thermodynamic functions of complexation between lanthanides(III) and 1,4,7-triazacyclononane (TACN) together with those of some of the above metal ions with the TACN-linear-analogue,N′-methyl-N′′-(2-(methylamino)ethyl)ethane-1,2-diamine (DMDIEN), are determined in dimethylsulphoxide (DMSO). The study aims to investigate the effect of ligand cyc...

Thermodynamic properties of the complexation of 2,2'-(trifluoroazanediyl)bis(N,N'-dimethylacetamide) (CF3ABDMA) with U(VI), Nd(III), and Np(V) have been studied in 1.0 M NaNO3 at 25 °C. Equilibrium constants of the complexation were determined by potentiometry and spectrophotometry. In comparison with a series of structurally related amine-bridged...

The solvation of the Co²⁺ ion in the [C4mim][Tf2N] (1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) room temperature ionic liquid (RTIL) has been studied from both a structural and thermodynamic point of view. Co K-edge X-ray absorption spectroscopy (XAS) data have been collected on a 0.1 M Co(Tf2N)2 solution in [C4mim][Tf2N] as well...

The adsorption of the neutral and zwitterionic forms of ciprofloxacin (CFX) on a single-walled carbon nanotube (SWCNT) has been studied by molecular dynamics (MD) simulations in gas phase and water. In both phases CFX remain adsorbed on the SWCNT during all simulation time. The interaction energies (Eint) are strongly negative and suggest a prefere...

The results of a potentiometric and calorimetric study on the complexation reactions of neutral N-donor ligands 1,4-diaminobutane (dab) and 1,5-diaminopentane (dap) with silver(I) in dimethylsulfoxide (DMSO) are reported. The investigation is extended for dab ligand to the aprotic solvent acetonitrile (AN), which presents quite different dielectric...

Data for complex formation of Co(II)with N-donors in dimethylsulfoxide are reviewed and rationalized on the basis of both solvational effects and ligand structural and electronic features. For the polyamine ligands, the number and stability of the species formed decreases with increasing number of N-methyl groups, due to the increase of the steric...

Molecular dynamics (MD) simulations and X-ray absorption spectroscopy (XAS) have been employed to study the solvation of the Zn²⁺ ion in the dry [Cnmim][Tf2N] (n = 2, 4; 1-ethyl-3-methylimidazolium and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide)room temperature ionic liquids (RTILs). For [C4mim][Tf2N] also the water-saturated sys...

This work presents the simple and low cost synthesis of a new tripodal ligand, in which three units of kojic acid are coupled to a tris(2-aminoethyl)amine (tren) backbone molecule. The protonation equilibria, together with the complex formation equilibria of this ligand with Fe3+, Al3+, Cu2+ and Zn2+ ions were studied. The complementary use of pote...

β-Cyclodextrin (β-CD) is a nontoxic cyclic oligosachcharide that can encapsulate all or part of organic molecules of appropriate size and specific shape through noncovalent interaction. Herein, we report the influence of β-CD complex formation of an antipyrine derivative on its metal ion sensing behavior. In aqueous solution, the antipyrine shows a...

In the present contribution, four classes of Ln(III) complexes (Ln = Eu and Tb) have been synthesized and characterized in aqueous solution. They differ by charge, Ln(bpcd)+ [bpcd2- = N,N′-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane N,N′-diacetate] and Ln(bQcd)+ (bQcd2- = N,N′-bis(2-quinolinmethyl)-trans-1,2-diaminocyclohexane N,N′-diacetate)...

Superparamagnetic iron nanoparticles (SPION) have been functionalized with 3-mercaptopropionic acid (3-MPA), characterized and applied for the removal of Ag⁺, Hg²⁺ and Pb²⁺ metal ions from aqueous solutions by iron oxide (Fe3O4). The heavy metal adsorption has been investigated by means of ICP-OES and isothermal titration calorimetry. Experimental...

The monofunctional platinum drug phenanthriplatin (phenPt) blocks the replication of cancer cells even if it reacts with only one guanine base. However, there is still insufficient experimental data to improve its cytotoxicity and all previously proposed chemical modifications of the parent structure have resulted in a loss of activity. We use theo...

It has been possible to obtain an unprecedented affinity towards hydrogen carbonate: the positively charged complexes reveal the highest logK values (5.76 and 5.94, respectively) reported up to now in the literature, for the formation of a luminescent adduct with hydrogen carbonate, characterized by an uncommon 1:2 stoichiometry.

A new MS-Excel utility based on the EST speciation tool (cEST) specifically designed to be applied to the analysis of calorimetric data is presented in this work. The cEST utility is able to fit calorimetric data with species of arbitrary stoichiometry and also automatically provides a complex statistical analysis of data fitting. This latter aspec...

Complexation of Np(V) with three structurally related amine-functionalized diacetamide ligands, including 2,2'-azanediylbis( N, N'-dimethylacetamide) (ABDMA), 2,2'-(methylazanediyl)bis( N, N'-dimethylacetamide) (MABDMA), and 2,2'-(benzylazanediyl)bis( N, N'-dimethylacetamide) (BnABDMA), in aqueous solutions was investigated. The stability constants...

The adsorption of Pt(IV) by iron oxide (Fe3O4) superparamagnetic nanoparticles (SPION) functionalized with 3-mercaptopropionic acid (3-MPA) is investigated by means of inductively coupled plasma optical emission spectrometry and isothermal titration calorimetry. Experimental ICP data are better fitted by Langmuir rather than Freundlich isotherms. T...

Manganese excess can induce in humans neurological disorders known as manganism. A possible remedy should be chelation therapy, even if a chelation schedule for manganism is not currently established. Para aminosalicylic acid (PAS) has demonstrated effectiveness in reducing manganism symptoms. In this work, a study of protonation equilibria of para...

The stability constants (log β), enthalpies of complexation (ΔH), and entropies of complexation (ΔS) for the complexes of uranium(VI) with a series of amine-functionalized diaetamide ligands, 2,2'-benzylazanediylbis(N,N'-dimethylacetamide) (BnABDMA), 2,2'-azanediylbis(N,N'-dimethylacetamide) (ABDMA), and 2,2'-methylazanediylbis(N,N'-dimethylacetami...

The coordination features and signaling of the L-lactate ion by a [Tb(bpcd)]+ (bpcd = N,N′-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane-N,N’-diacetate) complex have been investigated by means of a combination of techniques including total luminescence, calorimetry and circularly polarized luminescence. The L-lactate/[Tb(bpcd)]+ association con...

Adducts of TiCl4 with Lewis bases used as internal or external donors in heterogeneous Ziegler-Natta (ZN) catalysis represents a fundamental interaction contributing to the final composition of MgCl2 supported ZN-catalysts. This study presents the accurate experimental evaluation, from titration calorimetry, of the formation enthalpy of TiCl4 adduc...

The applicability of spectrophotometry or H⁺-potentiometry to the studies of the complexation of thorium(IV) in aqueous solutions is limited because Th(IV) does not have characteristic optical absorption in UV/Vis/Near IR region and H⁺-electrode is not sensitive in solutions of high acidity that needs to be maintained to prevent the hydrolysis of T...

The synthesis, crystal structure and spectroscopic properties of the neodymium(III) complex [Nd(btpa)Cl2]Cl.5H2O with btpa being the octadentate polypyridine ligand 6,6'-bis[bis(2-pyridylmethyl)aminomethyl]-2.2'-bipyridine are reported. The structure shows that the Nd³⁺ ion is coordinated to seven nitrogen atoms of btpa and two chloride ions, leavi...

Water-soluble Eu(III) and Tb(III) complexes with N,N'-bis(2-pyridylmethyl)-trans-1,2-diaminocyclohexane-N,N'-diacetic acid (H2bpcd) have been synthesized and characterized in their racemic and enantiopure forms. The ligand has been designed to bind Ln(III) ions, providing a dissymmetric environment able to solicit strong chiroptical features while...

The results of a potentiometric and calorimetric study on the complexation reactions of neutral N-donor ligands with silver(I) in propylenecarbonate (PC) and dimethylformamide (DMF) are reported. The ligands concerned in DMF are butylamine (n-but), 1,2-diaminoethane (EN), bis(2-aminoethyl)amine (DIEN) and N,N’-bis(2-aminoethyl)ethane-1,2-diamine (T...

The complexes of Cu(I) and Ag(I) with 1,3,5-triaza-7-phosphadamantane (PTA) are currently studied for their potential clin. use as anticancer agents, given the cytotoxicity they exhibited in vitro towards a panel of several human tumor cell lines. These metallodrugs were prepd. as [M(PTA)4]+ (M = Cu+, Ag+) compds. and dissolved in physiol. soln. fo...

In this paper the trifluoromethansulphonate (CF3SO3⁻, OTf⁻, triflate) Eu³⁺ complexes of a new family of imine-based ligands with 1:1 ligand to metal mole ratio have been employed for luminescence sensing of NO3⁻, F⁻, Cl⁻, Br⁻, I⁻, CH3COO⁻ and ClO4⁻, in non-anhydrous acetonitrile (wet AN = wAN) solution. The ligands show different donor ability and...

Poster related to the article with the same name.

The knowledge of the speciation of fluoroquinolones is of great actuality for the implications on the activity, bioavailability and pharmacokinetics. Literature reports a number of contrasting evaluations on the existence of tautomeric forms of mono-protonated species, described by a set of protonation micro-constants. Here the protonation sequence...

Platinum complexes bearing phosphane ligands in cis configuration with deprotonated flavonoids (3-hydroxyflavone, quercetin) and deprotonated ethyl gallate were synthesized starting from cis-[PtCl2(PPh3)2]. In all cases, O,O’ chelate structures were obtained. While quercetin and ethyl gallate complexes are quite stable in solution, the 3-hydroxyfla...

Mesoporous Hierarchical Alumina Microspheres (HAM) with high efficiency for fluoride removal have been synthesized and characterized. Two types of HAM, differing mostly in crystallinity, surface area and pore size have been obtained. Fluoride adsorption studies have been carried out by means of potentiometry and Isothermal Titration Calorimetry (IT...

The complex formation of nitrate ions with nickel(II) in dry [C4mim][Tf2N] ionic liquid (IL) was investigated by means of UV-visible spectrophotometry, isothermal titration calorimetry (ITC), extended X-ray absorption fine structure spectroscopy (EXAFS), and molecular dynamics (MD) simulations. EXAFS spectroscopy and MD simulations show that the so...

A new family of imine-based ligands containing pyridine or furan as aromatic donating ring [N, N’-bis(2-pyridylmethylidene)- 1,2-(R,R+S,S)-cyclohexanediamine, L1; N, N’-bis(2-furanylmethylidene)-1,2-(R,R+S,S)-cyclohexanediamine, L2 and N, N’-bis(2-thienylmethylidene)- 1,2-(R,S)-cyclohexanediamine, L3] has been prepared in high yield by means of an...

The complex formation between a cyclic ligand glutarimidoxioxime (denoted as HL(III) in this paper) and UO2(2+) is studied by potentiometry and microcalorimetry. Glutarimidoxioxime (HL(III)), together with glutarimidedioxime (H2L(I)) and glutardiamidoxime (H2L(II)), belongs to a family of amidoxime derivatives with prospective applications as bindi...

The hydration of the cisplatin aqua-derivatives, cis-[PtCl(H2O)(NH3)2]+ (w-cisplatin) and cis-[Pt(H2 O)2(NH3 )2 ]2+ (w2-cisplatin) has been studied by means of classical molecular dynamics simulations. The new platinum complex-water interaction potential, w-cisplatin-W, has been built on the basis of the already obtained cisplatin-water interaction...

A new family of imine and amine-based racemic ligands containing furan or pyridine as aromatic donating ring [N, N’-bis(2-pyridylmethylidene)- 1,2-(R,R+S,S)-cyclohexanediamine, L1; N, N’-bis(2-furanylmethylidene)- 1,2-(R,R+S,S)-cyclohexanediamine, L2; N, N’-bis(2-pyridylmethyl)- 1,2-(R,R+S,S)-cyclohexanediamine, L3 and N,N’-bis(2-furanylmethyl)-1,2...

The thermodynamic parameters for the complexation between the monodentate diethylsulfide (Et2S), the macrocyclic thioethers 1,4,7-trithiacyclononane ([9]aneS3) 1,4,7,10-tetrathiacyclododecane ([12]aneS4) and 1,4,8,11-tetrathiacyclotetradecane ([14]aneS4) have been determined in dimethylsulfoxide (DMSO) with d(10) metal ions such as Hg2+, Ag+, Cd(2+...

The thermodynamic parameters for the complexation reaction between Zn2+ and Hg2+ ions with the mixed amino-polypyridinic ligands tris[(2-pyridyl)methyl]amine (TPA) and 6,6-bis–bis (pyridylmethyl)aminomethyl]-2,2-bipyridine (BTPA) have been obtained in anhydrous dimethylsulfoxyde (DMSO) by using spectrophotometry, polarography, potentiometry and tit...

The hydration of cis-[PtCl2(NH3)2] (cisplatin) has been studied by means of classical molecular dynamics simulations using a new interaction potential obtained by fitting about 4000 ab initio interaction energies calculated at the MP2 level. The functional form included several r–n terms (n = 4, 6, 8, 12) to achieve an accurate description of the i...

In this paper a pyridine-based racemic ligand [N,N'-bis(2-pyridylmethylidene)-1,2-(R,R + S,S)-cyclohexanediamine], 1, and its new trifluoromethansulfonate (CF3SO3-, triflate) and nitrate Eu(III) complexes were studied, both in the solid state and in acetonitrile (AN) solution. In the case of the triflate complexes, a combination of structural and s...

Thermodynamic parameters of complex formation between d(10) metal ions, such as Zn(2+), Cd(2+), Hg(2+) and Ag(+), and the macrocyclic thioether 1,4,7-trithiacyclononane ([9]AneS3) or the monodentate diethylsulfide (Et(2)S), in acetonitrile (AN) at 298.15 K, were studied by a systematic methodology including potentiometry, calorimetry and polarograp...

There is a growing interest in the development of new medical diagnostic tools with higher sensibility and less damage for the patient body, namely on imaging reporters for the management of diseases and optimization of treatment strategies. This article examines the properties of a new class of lanthanide complexes with a tripodal tris-3-hydroxy-4...

The thermodynamics of the complexation between uranium(VI) and acetate in dimethyl sulfoxide (DMSO) was studied at 298 K in an ionic medium of 0.1 mol dm(-3) tetrabutyl ammonium perchlorate. The results show that the uranyl ion forms three strong successive mononuclear complexes with acetate. The complexes, both enthalpically and entropically stabi...