A highly selective acridine-based fluorescent probe for detection of Al in alcoholic beverage samples.

4,5-Bis(phtalimidomethyl)acridine (L) was studied as a chemosensor for metal ions in alcoholic matrices and showed to be selective for Al, through a linear fluorescence enhancement of 230% in the concentration range of 10-70 μmol L. Benesi-Hildebrand and Job's formalisms indicated the formation of a 1:1 (Al:L) complex with a binding constant of 6.30 × 10 L mol.

A Facile Preparation of a New Water-Soluble Acridine Derivative and Application as a Turn-off Fluorescence Chemosensor for Selective Detection of Hg.

A new acridine-based chemosensor was prepared, characterized and investigated for quantitative detection of Hg ions in aqueous solutions. DFT and TD-DFT calculations showed that formation of a coordination bond between Hg and the thiolate-sensor accounts for the fluorescence quenching, forming [HgLCl] as the most stable species. Limit of detection and limit of quantification were as low as 4.

DFT analysis of the linkage isomerism in penta(ammine)ruthenium(II/III) complexes of benzotriazole: Natural bond orbital method approach and a comprehensive energy decomposition analysis.

Penta(ammine)ruthenium benzotriazole complexes [Ru (NH ) bta] and [Ru (NH ) btaH] (bta and btaH are the deprotonated and neutral form of the triazole ligand, respectively) can exhibit two linkage isomers κN1 and κN2. This system was investigated by density functional theory natural bond orbitals analysis and Su-Li energy decomposition analysis. Steric, electrostatic, exchange, repulsion, polarization, and dispersion energy components of the total metal-ligand interaction were quantitatively evaluated, and revealed that the overall metal-triazole ligand is comprised of donor-acceptor interactions like σ-donation and π-back-donation, which favors a specific isomer depending on the oxidation state of the ruthenium and the charge of the ligand.

Metal complexes of a pentadentate N2O3bis(semicarbazone) Schiff-base. A case study of structure-spectroscopy correlation.

Schiff condensation of 2,6-diformyl 4-methylphenol with semicarbazide hydrochloride in 1:2 molar ratio produces the bis(semicarbazone) ligand, herein called H3L. A comprehensive spectroscopic analysis of the compound was performed by (1)H and (13)C NMR, FTIR and electronic spectroscopies. Assignments to the UV-vis spectrum of H3L were supported by semi-empirical quantum mechanics ZINDO/S calculations.

Crystal structure of 4-formyl-pyridine semicarbazone hemihydrate.

The mol-ecule of the title compound C7H8N4O·0.5H2O, alternatively called (E)-1-(pyridin-4-yl-methyl-ene)semi-carb-azide hemihydrate, is in the E conformation and is almost planar; the r.m.

Preparation, crystallography and spectroscopic properties of the polymeric {(1-(E)-2-pyridinylmethylidene)semicarbazone)(aqua)copper(II)} sulphate dihydrate complex: evidence of dynamic Jahn-Teller effect.

Pyridine-2-carbaldehyde semicarbazone ligand (HL) reacts with copper(II) sulphate in water solution to yield the coordination polymer [{Cu(II)(HL)(H(2)O)(SO(4))}(n)] (1). The crystals are triclinic with space group P(-1) and the metal ion is occupying a distorted octahedral geometry. EPR results show that a dynamic Jahn-Teller (J-T) effect is operative in water solutions and also support the stability of the polymeric chains as they continue to show a characteristic half-field Δm(S)=±2 transitions.

Bis(azido) alpha-iminooxime cobalt macrocyclic complex: synthesis, spectroscopy and ZINDO/S calculations.

Herein we report on the macrocyclic complex [Co(dohpn)(N3)2] (dohpn=2,3,9,10-tetramethyl-1,4,8,11-tetraazaundecane-1,3,8,10-tetraen-11-ol-1-olate). According to the MM+ optimized structure, it shows an octahedral environment around the metal ion with an overall planar configuration of the macrocyclic ligand, while azido ligands are not perpendicular to the plane of the macrocycle. Quantum mechanic calculations through semi-empirical methods were performed and a detailed spectroscopic (ZINDO/S) assignment is also presented.

A new pentanuclear cyano-bridged complex [(Fe(II)(tetraazamacrocycle))3{mu-NC-FeIII(CN)5)2]: synthesis, spectroscopic and magnetic characterization.

Hexacyanoferrate(III) reacts with [FeII(meso)(CH3CN)2](ClO4)2.2CH3CN (meso=5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) in acetonitrile/water mixture producing the title complex, where three [Fe(meso)]2+ units are connected by two [Fe(CN)6](3-) anions. Molecular modeling (MM+) shows a fairly linear molecule and Mössbauer data are consistent with two terminal pentacoordinated low spin iron(II)-meso units linked to one hexacoordinated low spin iron(II)-meso through two hexacoordinated low spin iron(III) units.

Mössbauer analysis of substituted diiron(II) tetraiminediphenolate macrocyclic complexes.

A new series of substituted diiron(II) complexes [Fe(2)(tidf)(L)(2)(MeOH)(2)](n+) (tidf=a two compartment tetraiminediphenolate macrocycle; n=0 or 2+; L=NCS(-), CN(-), N(3)(-), pyrazine (pz), 4-cyanopyridine (4-cnpy) and 4-mercaptopyridine (4-shpy)) and one tetranuclear complex, {[Fe(2)(tidf)(CH(3)OH)(2)](2)(mu-4-cnpy)(2)}(ClO(4))(4) were isolated and characterized by elemental analysis, conductivity measurements, Mössbauer and FTIR.

A comprehensive electronic structure description of a biscyanotetraazacobalt(III) macrocyclic complex.

Molecular modeling and a detailed spectroscopic characterization of the macrocyclic complex [Co(meso)(CN)(2)](+) (meso = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) is herein presented. Structural, electronic and vibrational features are discussed and assignments were proposed on the basis of semi-empirical (molecular mechanics (MM+), ZINDO/S and PM3) quantum-mechanics calculations. The energy and the composition of the molecular orbitals of the complex were calculated and a quantitative diagram was constructed.

Diruthenium, diiron and mixed ruthenium-iron tetraiminediphenolate macrocyclic complexes: synthetic route, spectroscopy, molecular mechanics and redox properties.

A series of diruthenium(II), [Ru(2)(tidf)Cl(2)(H(2)O)(2)] x H(2)O, diiron(II) [Fe(2)(tidf)(MeOH)(4)](ClO(4))(2) and mixed ruthenium(II)-iron(II) [Ru(MeOH)(2)FeCl(H(2)O)(tidf)](ClO(4)) (tidf=a two compartment tetraiminediphenolate macrocycle) complexes were prepared and characterized by elemental analysis, FTIR, UV-vis, cyclic voltammetry and semi-empirical molecular mechanics calculations.

ZINDO/S and PM3 calculations for a biscyanide alpha-iminooxime cobalt macrocyclic complex.

Molecular modeling and a detailed spectroscopic characterization of the macrocyclic complex [Co(dohpn)(CN)(2)] (dohpn=2,3,9,10-tetramethyl-1,4,8,11-tetraazaundecane-1,3,8,10-tetraen-11-ol-1-olate and py=pyridine) is herein presented. Structural, electronic and vibrational features are discussed and assignments were proposed on the basis of semi-empirical (molecular mechanics, ZINDO/S and PM3) calculations.

Synthesis and spectroscopic characterization of copper(II) tetraazaiminooxime macrocyclic complexes--a tetragonal distortion analysis.

Herein we describe the synthesis and spectroscopic (infrared and UV-vis) analysis of [Cu(II)(dohpn)(L)](n+) (dohpn=imineoximic tetraazamacrocyclic ligand 2,3,9,10-tetramethyl-1,4,8,11-tetraazaundecane-1,3,8,10-tetraen-11-ol-1-olate) and L=SCN(-), I(-), Cl(-) (n=0) and 4-aminopyridine (ampy), 4,4'-bipyridine (bipy), imidazole (im), 2-aminopyrazine (ampz) and water (n=1+). The following order of the Jahn-Teller stabilization energy (cm(-1)) was observed: I(-)(6452) View Article and Find Full Text PDF

Interaction of 2- and 4-mercaptopyridine with pentacyanoferrates and gold nanoparticles.

2-Mercapto- and 4-mercaptopyridine (2- and 4MPy) react with the [Fe(CN)(5)(H(2)O)](3-) complex, forming the S-coordinated [Fe(CN)(5)(2MPy)](3-) and the N-coordinated [Fe(CN)(5)(4MPy)](3-) complexes. The rates of formation and dissociation of the [Fe(II)(CN)(5)(2MPy)](3-) complex were determined as k(f) = 294 dm(3) mol(-1) s(-1) and k(d) = 0.019 s(-1) by means of stopped-flow technique.

Synthesis, characterization and semi-empirical calculations for the thiocyanate linkage isomers of an (alpha-iminooxime)cobalt(III) macrocyclic complex.

Herein we report the synthetic route and detailed characterization of the macrocyclic complex [Co(dohpn)(SCN)2] and its linkage isomer (dohpn=2,3,9,10-tetramethyl-1,4,8,11-tetraazaundecane-1,3,8,10-tetraen-11-ol-1-olate and py=pyridine) based on analytical, spectroscopic and electrochemical methods. Structural, vibrational and electronic features are discussed and a coherent assignment is proposed on the basis of semi-empirical theoretical calculations.

Spectroscopic, redox and magnetic properties of a tetraiminediphenolate iron(II) macrocyclic complex: a model compound for iron proteins.

The title complex [Fe(II)(tidf-H2)(H2O)2](ClO4)2*H(2)O (tidf-H2 = tetraiminediphenolate ligand) has been prepared from a transmetallation reaction between [Mg2(tidf)](NO3)2*4H2O and an iron(II) salt in methanolic solutions under inert atmosphere conditions. It was characterized by analytical, magnetic and spectroscopic methods (Mossbauer, FTIR, UV-vis), by cyclic voltammetry as well as spectroelectrochemistry.

Synthesis, spectroscopic characterization and semi-empirical calculations for a low spin carbonyl, pyridine(alpha-iminooxime)iron(II) macrocyclic complex.

Synthetic route and detailed characterization of the macrocyclic complex [Fe(II)(dohpn)(py)(CO)](ClO4) (dohpn = 2,3,9,10-tetramethyl-1,4,8,11-tetraazaundecane-1,3,8,10-tetraen-11-ol-1-olate and py = pyridine) based on analytical, spectrometric and spectroscopic methods are herein reported. The corresponding vibrational and electronic features are discussed and a consistent assignment is proposed on the basis of semi-empirical theoretical calculations.

Inner-Sphere Cluster Formation by [Ru(NH(3))(5)H(2)O](3+) or [Os(NH(3))(5)H(2)O](3+) in Combination with [M(CN)(6)](4)(-) (M = Fe, Ru, or Os).

When the cations [M'(NH(3))(5)H(2)O](3+) or [M'(NH(3))(5)H(2)O](2+) (M' = Ru, Os) are added in excess of the co-reactants [M(CN)(6)](4)(-) (M = Fe, Ru, Os), inner-sphere binding ends abruptly at the 4:1 ratio. The [M(CN)(6)](4)(-) --> [M'(NH(3))(5)](3+) charge transfer (CT) absorption shifts slightly to higher energy as the cations accumulate in the cluster, and there is a progressive decrease in intensity per additional oscillator introduced. The absorption bands and the electrochemical properties reveal the presence of isomeric forms in complexes of order 2 and above.