Risks and implications for health and the environment associated with products and waste containing nanomaterials: regulatory and management issues in the European framework.

Nanomaterials can revolutionize everyday products, but there are still many unanswered questions about the risks they may pose to human health and the environment. Inconsistent definitions and metrological issues are still of concern for manufacturers, importers and distributors who are demanded to comply with strict regulations. It is also likely that the increasing number of nanomaterial-containing products available on the market will vary the chemical and physical properties of the waste produced, which is currently treated in traditional plants without any particular differentiation.

Ultrarobust Thin-Film Devices from Self-Assembled Metal-Terpyridine Oligomers.

Ultrathin molecular layers of Fe(II) -terpyridine oligomers allow the fabrication of large-area crossbar junctions by conventional electrode vapor deposition. The junctions are electrically stable for over 2.5 years and operate over a wide range of temperatures (150-360 K) and voltages (±3 V) due to the high cohesive energy and packing density of the oligomer layer.

Active and non-active large-area metal-molecules-metal junctions.

The study of charge transport processes through organic molecules by using molecular junctions has generated great attention in the last few years, partially triggered by the possibility of developing molecular electronic devices to be implemented somehow into current silicon-based technology. As experimental tools, a large variety of conceptually and geometrically different metal-molecule(s)-metal junctions has been proposed. While the intrinsic conductivity of a molecule is still elusive, parameters crucial for molecular electronics have been extracted by using a variety of junctions.

A molecular clip throws new light on the complexes formed by a family of cyclam-cored dendrimers with Zn(II) ions. Efficient energy transfer in the heteroleptic complexes.

Complexation of Zn(II) ions by cyclam cored dendrimers appended with four (G0), eight (G1) and 16 naphthyl chromophores (G2) at the periphery have been investigated in CH₃CN-CH₂Cl₂ 1 : 1 (v/v) solution by absorption and emission, ESI-mass and ¹H NMR spectroscopy. The results obtained can be interpreted by the formation of complexes of 2 : 1 dendrimer to metal stoichiometry, at low metal ion concentration, and 1 : 1 complexes upon further addition of Zn(II) ions, for all the dendrimer generations. Upon addition of a molecular clip C²⁻ consisting of two anthracene sidewalls bridged by a benzene group with two sulfate substituents in the para positions, heteroleptic complexes of general formula [GnZnC] are formed.

Metal ion driven formation of a light-harvesting antenna investigated by sensitized luminescence and fluorescence anisotropy.

Zn(ii) complexation drives the formation of a light-harvesting antenna constituted by two multicomponent luminescent ligands: a cyclam-cored dendrimer decorated at the periphery with 16 naphthyl units and an anthracene-based molecular clip.

A light-harvesting antenna resulting from the self-assembly of five luminescent components: a dendrimer, two clips, and two lanthanide ions.

We have investigated the self-assembly of three luminescent species in CH(3)CN/CH(2)Cl(2), namely: 1) a polylysin dendrimer (D) composed of 21 aliphatic amide units and 24 green luminescent dansyl chromophores at the periphery, 2) a molecular clip (C) with two blue luminescent anthracene sidewalls and a benzene bridging unit that bears two sulfate groups in the para position, and 3) a near infrared (NIR)-emitting Nd(3+) ion. For purposes of comparison, analogous systems have also been investigated in which Gd(3+) replaced Nd(3+). The dendrimer and the clip can bind Nd(3+) ions with formation of [D.

Adducts between dansylated poly(propylene amine) dendrimers and anthracene clips mediated by Zn(II) ions: highly efficient photoinduced energy transfer.

A family of poly(propylene amine) dendrimers, decorated at their periphery with 4, 16, and 32 dansyl units and a molecular clip, composed of two anthracene sidewalls and a disulfate benzene bridging unit, show intense UV absorption and strong fluorescence in the visible region when in a CH(3)CN/CH(2)Cl(2) (1:1, v/v) solvent mixture. Both these classes of compounds are good ligands for Zn(II) ions, as demonstrated by the changes in the absorption and fluorescence spectra upon addition of metal ions. These coordinating properties have been exploited in the self-assembly of complex structures in which the interaction between a dansylated dendrimer and anthracene-functionalized clips is mediated by Zn(II) ions.

Molecular clips with extended aromatic sidewalls as receptors for electron-acceptor molecules. Synthesis and NMR, photophysical, and electrochemical properties.

We have synthesized molecular clips 1 comprising (i) two benzo[k]fluoranthene sidewalls and (ii) a dimethylene-connected benzene bridge that carries two acetoxy (1a), hydroxy (1b), or methoxy (1c) substituents in the para position. Their NMR spectra, single-crystal structures, and photophysical (fluorescence intensity, lifetime, depolarization) and electrochemical properties are discussed. For the purpose of comparison, similar compounds (2 and 3) containing only one benzo[k]fluoranthene unit have been prepared and studied.

Experimentally induced aggressiveness in heroin-dependent patients treated with buprenorphine: comparison of patients receiving methadone and healthy subjects.

Objective measures of experimentally induced aggressiveness were evaluated in heroin-dependent patients (HDP), 15 receiving buprenorphine (BUP) and 15 receiving methadone (METH) treatment. HDP were randomly assigned to BUP and METH groups. Fifteen healthy subjects (CONT) were included in the study as controls.

A cyclam core dendrimer containing dansyl and oligoethylene glycol chains in the branches: protonation and metal coordination.

We have synthesized a dendrimer (1) consisting of a 1,4,8,11-tetraazacyclotetradecane (cyclam) core, appended with four benzyl substituents that carry, in the 3- and 5-positions, a dansyl amide derivative (of type 2), in which the amide hydrogen is replaced by a benzyl unit that carries an oligoethylene glycol chain in the 3- and 5-positions. All together, the dendrimer contains 16 potentially luminescent moieties (eight dansyl- and eight dimethoxybenzene-type units) and three distinct types of multivalent sites that, in principle, can be protonated or coordinated to metal ions (the cyclam nitrogen atoms, the amine moieties of the eight dansyl units, and the 16 oligoethylene glycol chains). We have studied the absorption and luminescence properties of 1, 2, and 3 in acetonitrile and the changes taking place upon titration with acid and a variety of divalent (Co2+, Ni2+, Cu2+, Zn2+), and trivalent (Nd3+, Eu3+, Gd3+) metal ions as triflate and/or nitrate salts.

Study of the reaction of bis- and tris-pyrylium and -thiopyrylium cations with methoxide ion. Electronic effects of the heterocyclic rings as substituents.

The bis- and tris-pyrylium and thiopyrylium cations 1-4 were prepared in gram scale by heterocyclization of the corresponding bis- and tris-1,5-pentanediones 6 and 8. Their reaction with CD3ONa in CD3OD was studied by 1H NMR at -40 degrees C and at +25 degrees C. At low temperature, kinetically controlled mixtures of 2H and/or 4H adducts were detected, whereas at room temperature the mixtures equilibrated to yield, in all of the cases, the more stable 2H adducts exclusively.

Kinetics of oxidation of benzyl alcohols by the dication and radical cation of ABTS. Comparison with laccase-ABTS oxidations: an apparent paradox.

Laccase, a blue copper oxidase, in view of its moderate redox potential can oxidise only phenolic compounds by electron-transfer. However, in the presence of ABTS (2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonate) as a redox mediator, laccase reacts with the more difficult to oxidise non-phenolic substrates, such as benzyl alcohols. The role of ABTS in these mediated oxidations is investigated.

The role of aromatic radical cations and benzylic cations in the 2,4,6-triphenylpyrylium tetrafluoroborate photosensitized oxidation of ring-methoxylated benzyl alcohols in CH2Cl2 solution.

A steady-state and laser flash photolysis (LFP) study of the TPPBF(4)-photosensitized oxidation of ring-methoxylated benzyl alcohols has been carried out. Direct evidence on the involvement of intermediate benzyl alcohol radical cations and benzylic cations in these reactions has been provided through LFP experiments. The reactions lead to the formation of products (benzaldehydes, dibenzyl ethers, and diphenylmethanes) whose amounts and distributions are influenced by the number and relative position of the methoxy substituents.