A New Ratiometric Lysosomal Copper(II) Fluorescent Probe To Map a Dynamic Metallome in Live Cells.

We synthesized a new ratiometric fluorescent Cu probe, bearing a morpholine moiety for selective binding to lysosomes and two picolylamine arms for the specific chelation of divalent copper ions. The probe capability to detect lysosomal Cu was demonstrated in human differentiated neuroblastoma cells by confocal microscopy.

A novel porphyrin-based molecular probe ZnTCPPSpm4 with catalytic, stabilizing and chiroptical diagnostic power towards DNA B-Z transition.

In this work we have designed a new zinc(II) porphyrin with four spermines conjugate in the meso positions, meso-tetrakis-(4-carboxysperminephenyl)porphyrin, ZnTCPPSpm4) with the aim of acting as a chiroptical probe for the Z-form of DNA, a high energy transient conformation of DNA. In addition to monitor by Electronic Circular Dichroism chiroptical response the formation of Z-DNA in the presence of micromolar concentration of spermine, this porphyrin based molecular probe is also able to catalyze and stabilize this important DNA structure. The ZnTCPPSpm4 conjugate represents a perfect example of single molecule, which possesses all these three properties at the same time.

Fluorescent Copper Probe Inhibiting Aβ1-16-Copper(II)-Catalyzed Intracellular Reactive Oxygen Species Production.

A variety of fluorescent probes are proposed to monitor the intracellular copper content. So far, none of the probes have been evaluated for their potential to inhibit copper-associated intracellular oxidative stress. Herein, we studied the ability of a fluorescent copper probe, OBEP-CS1, to inhibit intracellular oxidative stress associated with an amyloid β (Aβ) peptide-copper complex.

Nerve Gas Simulant Sensing by a Uranyl-Salen Monolayer Covalently Anchored on Quartz Substrates.

A uranyl complex monolayer that easily allows the optical detection of a nerve gas simulant, namely, dimethyl methylphosphonate, is reported. Both UV/Vis spectroscopy and photoelectron data confirm that the functional hybrid material coordinates a Lewis base by means of the P=O group, which interacts with the uranium equatorial site available for complexation.

The memory-driven order-disorder transition of a 3D-supramolecular architecture based on calix[5]arene and porphyrin derivatives.

A 3D supramolecular polymer based on calix[5]arene tethered poly(p-phenyleneethynylene) with a complementary porphyrin endowed with alkanediyldiammonium functions is prepared in solution but collapses when transferred to a chemically inert solid matrix forming a dispersion of de-phasing porphyrin aggregates. We found that a short thermal shock induces the de-aggregation of the porphyrin aggregates, and a partial restoration of the original 3D-supramolecular architecture.

(Salen)Mn(III) Catalyzed Asymmetric Epoxidation Reactions by Hydrogen Peroxide in Water: A Green Protocol.

Enantioselective epoxidation reactions of some chosen reactive alkenes by a chiral Mn(III) salen catalyst were performed in H₂O employing H₂O₂ as oxidant and diethyltetradecylamine N-oxide (AOE-14) as surfactant. This procedure represents an environmentally benign protocol which leads to e.e.

Synthesis, Structural Characterization, and Chiroptical Studies of Bidentate Salen-Type Lanthanide (III) Complexes.

The salen-type ligand prepared with (R,R) diphenylethan-1,2-diamine and salicylaldehyde provides stable and inert complexes KLnL2 upon simple reaction with lanthanide halides or pseudohalides LnX3 (Ln = Tb(3+) -Lu(3+) ; X = Cl(-) or TfO(-) ) of its potassium salt. All the complexes were completely characterized through nuclear magnetic resonance (NMR), electronic circular dichroism (ECD) in the UV and some (Er(3+) , Tm(3+) , Yb(3+) ) also with Near-IR ECD (NIR-ECD) and luminescence (Tb(3+) , Tm(3+) ). Careful analysis of the NMR shifts demonstrated that the complexes are isostructural in solution and afforded an accurate geometry.

A novel fully water-soluble Cu(I) probe for fluorescence live cell imaging.

A new Cu(I) probe (OBEP-CS1), bearing an alkyl-pyridinium moiety to get complete water solubility, was synthesized. Fluorescence titrations support copper binding and high selectivity in a water solution whereas formation of aggregates was excluded by DOSY experiments. The detection capability for intracellular Cu(I), especially localized in mitochondria, was demonstrated in differentiated neuroblastoma cells by confocal microscopy.

Enantioselective extraction mediated by a chiral cavitand-salen covalently assembled on a porous silicon surface.

A chiral organic-inorganic hybrid material, based on a porous silicon surface functionalized with a chiral cavitand, was designed and synthesized. The affinity of this device in water toward a bromine-marked alkyl-ammonium salt has been evaluated using XPS detection. UV and CD measurements highlight the enantioselective extraction from a racemic mixture in water of the S-enantiomer of the selected guest (ee ≥ 80%).

Novel chiral (salen)Mn(III) complexes containing a calix[4]arene unit in 1,3-alternate conformation as catalysts for enantioselective epoxidation reactions of (Z)-aryl alkenes.

Two new chiral calix[4]arene-salen ligands 1a,b, based on calix[4]arene platforms in 1,3-alternate conformation, have been prepared by a new general synthetic pathway. Their Mn(III) complexes, 3a,b have shown fairly good efficiency in the asymmetric epoxidation of styrene and substituted styrenes, whereas excellent catalytic activity and selectivity were observed with rigid bicyclic alkenes, namely 1,2-dihydro-naphthalene and substituted 2,2'-dimethyl-chromene. The higher catalytic properties of 3a may be ascribed to the more rigid and inherently chiral structure as proved by molecular modelling, NMR spectroscopy and X-ray data of the similarly structured UO2 complexes 2a,b.

Selective oxidation reactions of natural compounds with hydrogen peroxide mediated by methyltrioxorhenium.

We have investigated the oxidative behaviour of natural compounds such as methyl abietate (1), farnesyl acetate (2), α-ionone (3), β-ionone (4), methyl linolelaidate (5), methyl linolenate (6) and bergamottin (7) with the oxidant system methyltrioxo-rhenium/ H2O2/pyridine. The reactions, performed in CH2Cl2/H2O at 25 °C, have shown good regio- and stereoselectivity. The oxidation products were isolated by HPLC or silica gel chromatography and characterized by MS(EI), 1H-, 13C-NMR, APT, gCOSY, HSQC, TOCSY and NOESY measurements.

A ratiometric naphthalimide sensor for live cell imaging of copper(I).

A new naphthalimide derivative bearing a tetrathia-azacrown for high affinity and selective binding to Cu(+) was synthesised. Copper recognition properties in solution were evaluated using (1)H NMR and fluorescence spectroscopy. Live cell imaging by confocal microscopy highlighted the capabilities of the new sensor for the two-wavelength detection of intracellular monovalent copper in neuronal cells.

Pair of diastereomeric uranyl salen cavitands displaying opposite enantiodiscrimination of α-amino acid ammonium salts.

A pair of diastereomeric salen cavitands and their uranyl complexes combine a chiral (R,R) salen bridge and an inherent chiral tris-bridged quinoxaline cup within the same molecule. Whereas the free ligands show a preference for the same enantiomer of an α-amino acid pair, the corresponding UO(2) complexes display opposite enantiodiscrimination and exceptionally high enantioselectivities (K(D)/K(L) = 26.4).

An integrated X-ray and molecular dynamics study of uranyl-salen structures and properties.

Uranium complexes of bis(p-tert-butyl-salicylidene)-1,2-diphenylethylenediamine (1) and bis(salicylidene)-1,2-diphenylethylenediamine (2) have been synthesized and investigated by X-ray single crystal diffraction and MD calculations in Periodic Boundary Conditions. Both compounds form crystals which are densely packed and do not provide voids accessible to solvent molecules. The configurations adopted by 1 and 2 are determined by well defined T-shaped and π-stacking non covalent interactions between phenyl groups of adjacent molecules as well as by a network of hydrogen bonds.

Reversible mutarotation in a macrocyclic ytterbium complex.

M40 is a four-fold symmetry macrocyclic ligand endowed with axial and central chiral elements, all of R configuration. It promptly binds late lanthanides (Yb(III) and Lu(III) ) yielding a negative helicity, as witnessed by NIR-electronic circular dichroism. In the course of a few hours, a new conformation of the complex takes over, which has opposite helicity and allows for a dynamic free-bound equilibrium.

Viable route for switching of an engineered silica surface using Cu2+ ions at sub-ppm levels.

Quartz substrates were functionalized with a covalent 4-ClCH(2)C(6)H(4)SiCl(3) monolayer. To this, N-(4-hydroxyphenethyl)-4,5-di[(2-picolyl)amino]-1,8-naphthalimide molecules were then covalently bonded, producing a new monolayer of these molecules on silica substrates. The surface chemical characterization of this hybrid material was carried out by X-ray photoelectron spectroscopy.

Synthesis and conformational study of a novel macrocyclic chiral(salen) ligand and its uranyl and Mn complexes.

A novel chiral macrocyclic ligand incorporating a chiral salen moiety into a framework containing two biphenyl units was synthesized. Structural properties and conformational aspects of the free ligand and an UO2 complex were studied by using NMR spectroscopy in solution and MM calculations. The Mn(III) complex was tested as catalyst in enantioselective oxidation of prochiral unfunctionalized olefins to the corresponding optically active epoxides under very mild conditions.

Recognition of achiral and chiral ammonium salts by neutral ditopic receptors based on chiral salen-UO2 macrocycles.

A mononuclear (M20) and a dinuclear (M40) uranyl chiral macrocyclic complex, incorporating both a salen unit containing two phenyl rings linked to a chiral diimine bridge and the (R)-BINOL unit, behaves as an efficient ditopic receptor for achiral and chiral quaternary ammonium salts. Binding affinities in chloroform solution have been measured for 1:1 complexes of many quaternary salts encompassing tetramethylammonium (TMA), tetraethylammonium (TEA), tetrabutylammonium (TBA), and acetylcholine (ACh), as well as trimethylanilinium (TriMAn), benzyltrimethylammonium (BnTriMA), (alpha-methylbenzyl)trimethylammonium and pyrrolidinium cations. The anion of the salt is bound by the hard Lewis acidic uranyl site, with an increasing binding efficiency on increasing the anion hardness (I(-) < Br(-) < Cl(-)), whereas CH-pi or pi-pi attractions by binapthyl moiety, or the salicylaldehyde unit, or the phenyl rings of diimine bridge ensure the recognition of the cation partner.

Conversion of oximes to carbonyl compounds by triscetylpyridinium tetrakis(oxodiperoxotungsto) phosphate (PCWP)-mediated oxidation with hydrogen peroxide.

Aromatic and aliphatic oximes have been deoximated in chloroform-water to the corresponding aldehydes with dilute hydrogen peroxide and triscetylpyridinium tetrakis (oxodiperoxotungsto) phosphate as catalyst. The presence of dipolarophiles in the reaction mixtures allows a competitive reaction that converts oximes into isoxazole and isoxazoline derivatives via the intermediate formation of nitrile oxide species.

Electronic properties of some nitrobenzo[a]pyrene isomers: a possible relationship to mutagenic activity.

Ionization potential (IP), electron affinity (EA), dipole moment (mu) and electronic polarizability (alpha) of 1-, 3- and 6-nitrobenzo[a]pyrene isomers (1-NBaP, 3-NBaP, 6-NBaP) were determined by using density functional theory (DFT) and recent semiempirical PM6 methods. Calculated IP value remains almost constant along the series of isomers, while EA value depends on the nitro group position, increasing by ca. 0.

Regio and stereoselective oxidations of unsaturated steroidal compounds with H2O2 mediated by CH3ReO3.

We have investigated the oxidative behavior of sterols such as cholesteryl acetate (1), 7-dehydrocholesteryl acetate (2), ergosteryl acetate (3), cholecalciferol acetate (Vitamin D(3) acetate) (4) and ergocalciferol acetate (Vitamin D(2) acetate) (5) with the oxidant system methyltrioxorhenium/H(2)O(2)/pyridine in order to check potential parameters controlling the selectivity. The reactions, performed in CH(2)Cl(2)/H(2)O at 25 degrees C, have shown good regio- and stereoselectivity. All oxidation products were isolated by high-performance liquid chromatography (HPLC) and characterized by MS(EI) or FAB, (1)H NMR, (13)C NMR, APT, COSY, HSQC, HMBC, ROESY and NOEDS measurements.

Optimization of supercritical fluid extraction by carbon dioxide with organic modifiers of polycyclic aromatic hydrocarbons from urban particulate matter.

The main advantages of using supercritical fluids for the extractions of organic pollutants from environmental matrix is that they are inexpensive, contaminant free, and less costly to dispose safely than organic solvents. In this work, a series of extraction experiments were carried out using CO2 as supercritical fluid on a certified sample of "Urban dust" (NIST S.R.

OH-initiated oxidation of monoterpenes: reaction of alpha-pinene.

The aim of this paper is to study the reaction products of alpha-pinene, beta-pinene, limonene, 3-carene and sabinene with OH radicals by FT-IR spectroscopy and by HPLC-MS-MS, to evaluate the secondary aerosol formation. All gas phase reaction products were quantified using reference compounds. As source of OH radicals were used H2O2 and CH3ONO.

Multiplicity of Reaction Pathways in the Processes of Oxygen Transfer to Secondary Amines by Mo(VI) and W(VI) Peroxo Complexes.

Oxidation of N,N-benzylmethylamine, N,N-benzylisopropylamine, and N,N-benzyl-tert-butylamine by both anionic and neutral Mo(VI) and W(VI) oxodiperoxo complexes yields the corresponding nitrones quantitatively. The oxidation reactions employing anionic oxidants were performed in CHCl(3) and follow second-order kinetics, first order with respect to the amine and to the oxidant. The data were rationalized on the basis of a rate-determining nucleophilic attack of the amine onto the peroxide oxygen of the oxidant, with a transition state in which N-O bond formation and O-O bond cleavage occur in a concerted way (electrophilic oxygen transfer mechanism).