1,721,043 research outputs found
Metal-Oxicam Complexes from X-Ray Structure to Innovative Ways for Drug Delivery
No full textSynthesis, structural and chemical characterization and evaluation of the selected biological and biological properties (antiinflammatory and cytotoxic) of Copper, Ruthenium, Platinum complexes from the laboratory directed by the authors at Department of chemistry, University of Sien
Heavy metals in drinking waters from Mount Amiata (Tuscany,Italy). Possible risks from arsenic for public health in the Provinceof Siena
No full textConcentrations of As, Al and some heavy metals (V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Cd, Pb) were measured in
drinking waters from Siena and Grosseto districts, South Tuscany, Italy. The analysis, performed mostly by
electrothermal activated atomic absorption spectroscopy equipped with graphite furnace, and in some cases highresolution
inductively coupled plasma mass spectrometry, indicated that concentrations of the elements were generally
far below the maximum allowed concentration (MAC). However, the concentration of As in some of the waters at
sources or at the terminals of the water webs was relatively high (largest value, 14.4(2) mgyl) when compared to the
MAC value (As 10 mgyl, December 25, 2003; Italian Law). Relatively high concentrations of some metals had been
detected in a few samples from the ends of the distribution webs, when compared to values at sources. These effects
are probably due to leaching from metal pipes. A general ‘metal index’ (MI) for drinking water, which takes into
account possible additive effects of N heavy metals on the human health that helps to quickly evaluate the overall
quality of drinking waters, is introduced in this paper as MIs8is1,NwCiy(MAC)ix. Samples from Ermicciolo spring
and Siena water web had MI values of 1.1 and 1.3, respectively, showing that the quality of drinking water in town
is somewhat worse than that at one of the main sources, at least regarding the 12 elements taken into account.
2003 Elsevier B.V. All rights reserved
Study of binary and ternary metal complexes containing the sulfato ligand: Molecular models for selected non-catalytic sites in sulfurylase
No full text[CdII(Î1⁄42-O2,Oâ 2, Oâ 3-SO4)(terpy)]2·2H2O, 1·2H2O (terpy, 2,2â 2:6â 2,2â 3-terpyridine) was obtained from the reaction of 3 CdSO4·8H2O with terpy and consists of centrosymmetric dimeric units in which the two Cd(terpy)2+ moieties are held together by two tridentate sulfato anions that act as chelators towards the two metal centres, one oxygen being tri-coordinate. This coordination mode for the sulfato ligand has never been reported before in the solid state. [ZnII(Î1⁄42-O,Oâ 2-SO4) (terpy)]2·2H2O, 2·2H2O, was obtained by using ZnSO4·7H2O through a procedure similar to that followed for 1·2H2O. Semi-empirical quantum mechanics and density functional structure optimisations were performed at the AM1 and Becke3LYP/(6-31 G**, S) levels. The computations reproduced well the main features of the Zn(Î1⁄42-O,Oâ 2-SO4)2Zn unit as found in 2. A [Zn(imidazole)2(O-OOCCH3)2 (O-SO4)]2- model was also optimised as a model for ATP-sulfurylase from Saccharomices cerevisae
Innovation on Metal Based Drugs. Design, SynthesisCharacterization and delivery for Coordination Compounds Containing Active Drugs
No full textThe synthesis, structural characterization and evaluation of cytotoxic activity of Pt(NH3)2(Oxicamato)2 complexes has been reported and innovative strategies for administration in living tissues have been designed and performed as based on smart hydrogel
Selected Volatile Compounds and Inorganic Speciesin Wines: Effects on Quality and Aroma.
No full textRuthenium complexes as nitric oxide donors and scavengers. Synthesis and crystal and molecular structure for mer,trans-[RuIICl3(NO+)(N-4-ethylisonicotinate)2], and mer,trans-[RuIIICl3(N-CH3CN)(N-4-ethylisonicotinate)2] as obtained via UV-photochemical activation of {RuII(NO+)}3+-core parent complex in acetonitrile solution
No full textThe synthesis of mer,trans-[(RuCl3)-Cl-II(NO+)(EINT)(2)](EINT = N-4-ethylisonicotinate), 1, was achieved by carefully working under ultrapure nitrogen atmosphere, by mixing (RuCl3)-Cl-III(NO)center dot H2O and EINT (1:2 M ratio in anhydrous ethanol) under stirring and at reflux conditions. Single crystals of 1 suitable for X-ray diffraction XRD techniques were also obtained by slow evaporation of solvent under nitrogen from the mother alcoholic solution. The IR spectrum of the solid (KBr matrixes) showed the characteristic sharp and intense band (1866 cm(-1)) relevant to the N-O stretching vibration for the nitrosyl ligand (Ru-II-NO+ core). Then, on irradiating at 25 degrees C a solution of 1 in ultrapure acetonitrile (contained in quartz cuvette) under an UV source (250 throughout 366 nm) a color turning from pink to yellow occurred. After a prolonged irradiation (250 nm for at least 6 h) the cuvette (yellow solution) was stored in a dry nitrogen atmosphere and allowed to slowly concentrate via spontaneous solvent evaporation. The solution produced brown crystals as parallelepipeds, suitable for XRD data collection, that belong to the monoclinic system, C2/c space group, and the molecular structure (mer,trans-[(RuCl3)-Cl-II(N-NCCH3)(EINT)(2)], 2) consists of complex molecules that are mostly paired via stacking interactions that involve the pyridine moiety and through (ethyl)CH3 center dot center dot center dot Cl(Ru), (pyridine)CH center dot center dot center dot Cl(Ru) and (ethyl)CH3 center dot center dot center dot O(=C) hydrogen bond type interactions. The crystals of the parent nitrosyl complex belong to the orthorhombic Pccn space group and the complex molecule has three chlorido ligands in the equatorial positions and two EINT ligands in the axial positions. The nitrosyl ligand occupy two positions that are trans to each other and have half occupancy each
Synthesis, and electrochemical and density functional studies of new copper(II)- and manganese(II) -oxicam drugs. Redox potentials and MOs compatible with SOD-like activity and unusual six-membered rings of water molecules bridging complex units
No full textThe synthesis and rare structures of Mn-II and Cu-II complexes with OXI drugs (oxicam, a family of non-steroidal anti-inflammatory drugs) are reported. On mixing Mn-II acetate with piroxicam (H2PIR) pale yellow single crystals of trans,trans-[Mn-II(O-N,N-DMF)(2)(N,O-HPIR)(2)], 1, dimethylformamide (DMF), were obtained. The structure shows two HPIR- anions chelate through pyridyl nitrogen and amide oxygen, and two positions around the metal atom are occupied by the two DMF molecules. The Mn-O(amide, HPIR) vector is much shorter than the two other coordination vectors, a novelty for M-II(L)(2)(HOXI)(2) molecules. Single crystals of trans,trans-[Cu-II(H2O)(2)(N,O-HTEN)(2)]center dot 4H(2)O center dot 2DMF, 2, (H2TEN, tenoxicam,) were obtained by long storage from DMF solutions of Cu-II(HTEN)(2) during loading smart synthetic hydrogels. Compound 2 is the first example for M-II(HOXI)(2) units, linked to H2O molecules ever reported, and extensive networks of H2O center dot center dot center dot OH2 hydrogen bonds and Cu center dot center dot center dot OH2 bonds that involve six member cycles of water molecules arranged as puckered rings bridging M-II(HOXI)(2) entities. Infrared bands related to amide groups for HOXI- ligands are significantly influenced by the strength of M-O bonds in agreement with bond length trends. Electrochemical studies for Cu-II(HTEN)(2) in tetrahydrofuran are in agreement with a SOD-like scavenger activity at least for superoxide oxidation to molecular oxygen, E degrees(Cu-II/Cu-I, SCE) -0.31V. Furthermore, density functional investigation at the gas phase reproduces well the structure for trans,trans-[Mn-II(O-DMF)(2)(N,O-HPIR)(2)] sextuplet molecule and for trans,trans-[Cu-II(H2O)(2)(N,O-HTEN)(2)] doublet molecule. Even a model of the {Cu-II(HTEN)(2)(OH2)center dot center dot center dot(H2O)(4)center dot center dot center dot(H2O)Cu-II(HTEN)(2)} entity found for 2 is well reproduced by theory. The estimate stabilization energy brought about by the six water molecules ring between two Cu-II(HTEN)(2) molecules is 69 kcal
A Molecular Orbital Study of C-H...Cl- and N-H...Cl- Hydrogen Bonds. Inferences on Selected Metal Complexes and on Protein ClC Cl- Channels
No full textHydrogen bond type interactions X–H···Y– (X: C, N, O; Y: Cl) for systems that contain 1,3-imidazole (IM), 1,3-pyrimidine
(PYM), N-methylacetamide (MAA), methylammonium (MA), methylamine (MAB), 1-hydroxy-4-methylbenzene (HMB),
N-methylguanidinium (MGU), methanol (MeOH), have been investigated via the methods of density functional theory (DFT) at
the B3LYP functional level and ab initio MP2, by using mostly the standard 6-31G** and 6-31+G** basis sets. The study helps
in understanding structural aspects of at least Re/Ru-imidazole, Ru-pyrimidine and Ru-arene complexes and allows to evaluate
the adduct formation energy (electronic), for species of the type M(IM)N–H···Cl–, M(IM/PYM)C–H···Cl–, whose upper limits
are ca. –24 and –10 kcal at gas phase. Computed structural and energy parameters help also in evaluating the mechanism of
extrusion of Cl– anions in certain ClC Chloride channels from membrane proteins. The hydrogen bond formation energy for
selected aminoacid residues with Cl– ranges ca. –106 to –15 kcal mol–1. Owing to the predominance of CONH peptide bonds in
every protein system, the formation of the C(=O)–N–H···Cl– hydrogen bond (DEel ≈ –21 kcal) is often revealed in X-ray structures
of protein···chloride adducts
Copper(I)-alkyl sulfide and -cysteine tri-nuclear clusters as models for metallo proteins: a structural density functional analysis
No full textfter having set up the computational methodology for Cu(I)-sulfur systems as models for copper proteins, namely using the simple ligands H(2)S, HS(-), CH(3)SH, and CH(3)S(-), the Cu(I)-Cysteine systems have been investigated: [Cu(I)( S -H(2)Cys) (n) ](+) (H(2)Cys, cysteine, NH(2),SH,COOH) [Cu(I)( S -HCys) (n) ](1-) (n) (NH(2),S(-),COOH). Finally, the structures for bi-nuclear [Formula: see text] (Et, CH(2)CH(3)), [Formula: see text] and tri-nuclear [Cu(I)( S -SH)](3), [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] (NH(2),SH,COOH), [Formula: see text] (NH(2),S(-),COOH, and NH(2),SH,COO(-)), as well as [Formula: see text] (NH(2),S(-),COO(-)), were also optimized to mimic the active center for a metallo-chaperone copper transport protein (CopZ). The X-ray structures for the biomolecules were matched fairly well as regards the Cu-S bond distances and Cu...Cu contact distances in the case the model cysteine S atom is deprotonated. Upon protonation of ligand S atoms, the conformation of clusters is altered and might bring about the di- and tri-nuclear core breakage. These findings suggest that subtle protonation/deprotonation steps, i.e. small and/or local pH changes play a significant role for copper transport processes
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