Studies of the complexation behavior of tetramorpholinylo-PNP-lariat ether with Ag(I), Ca(II), Cd(II), Cu(II) and Pb(II) using Electrospray Ionization Mass Spectrometry

In this publication the cationic metal complexes of tetramorpholinylo-PNP-lariat ether have been studied using electrospray ionization mass spectrometry (ESI-MS). The tandem mass spectra (MS/MS) of these complexes have also been tested to evaluate the stability of the different types of the complexes formed. As occurred, all selected metal cations form the complexes with 1 : 1 stoichiometry with the investigated ligand. Only silver ions create a ‘‘sandwich’’ type complex. Furthermore, the divalent cations form complexes with the nitrate anion adduct. In the case of Ca(II), Cd(II) and Pb(II) we also observed another type of the species with an additional water molecule attached to the parent complex

Electronic and optical properties of 5-AVA-functionalized BN nanoclusters: A DFT study

We carried out detailed density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations upon 5-aminolevulinic acid-functionalized B12N12 and B16N16 nanoclusters with the B3LYP, B3PW91, and PBE methods using the 6-311+G∗∗ basis set. The calculated adsorption energies of 5-aminolevulinic acid with the BN nanoclusters were evaluated at T = 298.15 and 311.15 K in the gaseous and aqueous environments with the B3LYP, B3PW91, and PBE methods. Our results showed that the adsorption of the 5-AVA molecule (NH2 group) with B12N12 is more favorable than-with the B16N16 nanocluster in the gas and solvent phases. It is anticipated that a 5-aminolevulinic acid (5-AVA) drug incorporating BN clusters could find application in drug delivery systems and in biomedical devices. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2016

Interaction of aluminium hydrolytic species with biomolecules

In this contribution the formation of bioinorganic assemblies between the basic globular protein lysozyme and aqueous aluminium species including Al 13 -mer, Al 30 -mer and colloidal aluminium hydroxide have been explored and comparison made to previous interaction studies performed with bovine serum albumin (BSA). Specific charge-stabilised bioinorganic assemblies involving aluminium species and lysozyme were observed to form in contrast to the gel like structures formed on interaction of BSA with aluminium species. As demonstrated by infrared spectroscopy (structural assignment, 2D correlation spectroscopy), interactions mostly involve acidic surface groups of the proteins (Asp, Glu), with strong complexation and deprotonation in the case of BSA interacting with Al 13 and Al 30 and through hydrogen bonding for lysozyme interacting with the same species and aluminium hydroxide particles interacting with both biomolecules

Luminescent coordination polymers based on Ca²⁺ and octahedral cluster anions [{M₆Clⁱ₈}Clᵃ₆}²⁻ (M = Mo, W) : synthesis and thermal stability studies

Luminescent coordination polymers (CPs) based of inexpensive stable precursors are attractive materials for applications. Here we report the synthesis and evaluation of the stability and photophysical characteristics of the first examples of phosphorescent CPs based on octahedral molybdenum and tungsten cluster anions. Specifically 1D CP trans-[{Ca(OPPh₃)₄}{{M₆Clⁱ₈}Clᵃ₆}]∞ (M = Mo, W) can be obtained either directly at increased temperature or via intermediate phases [cis-Ca(OPPh₃)₄(H₂O)₂][{M₆Clⁱ₈}Clᵃ₆]∙2CH₃CN that are stable at room-temperature, but convert to the titled CP at temperatures above 100 °C

Surface area or diameter – which factor really determines the antibacterial activity of silver nanoparticles grown on TiO₂ coatings?

Titanium dioxide coatings were prepared on Si wafers using the sol–gel method. Four different types of coatings with silver nanoparticles (AgNPs) were synthesized. The diameter and surface density of AgNPs were conditioned by the concentration of Ag+ ions in the initial solution, time and UV illumination source. The bactericidal activity of AgNPs on the titanium dioxide coatings against the S. aureus strain were calculated as the percentage of the inhibition of bacterial growth after 24 hour incubation of microorganisms at 37°C on TiO₂ coatings with AgNPs. Control samples were coated with titanium dioxide without AgNPs. We concluded that the titanium dioxide coatings modified with silver nanoparticles had a high antibacterial activity. Moreover, we demonstrated strong dependence between surface areas of AgNPs and inhibition of bacterial growth. The obtained results evidence that the surface area of AgNPs grown on titanium dioxide coatings is a major factor determining their antimicrobial potential

Water-soluble hybrid materials based on {Mo₆X₈}⁴⁺ (X = Cl, Br, I) cluster complexes and sodium polystyrene sulfonate

Development of water-soluble forms of octahedral molybdenum clusters {Mo₆X₈}⁴⁺ (X = Cl, Br, I) is strongly motivated by the tremendous potential that these complexes have for biological applications, namely as agents for bioimaging and photodynamic therapy. In these work we report the first water-soluble hybrid materials, which represent sodium polystyrene sulfonate doped by molybdenum clusters, and evaluation of their photophysical and biological properties (dark and photoinduced cytotoxicity and cellular uptake) with the use of cervical cancer (HeLa) and human epidermoid larynx carcinoma (Hep-2) cell-lines as models

Le tourisme scientifique : un essai de définition

International audienceThis article focuses on the notion of scientific tourism. It offers through a literary review to distinguish four distinct forms, practices and related tourism products, that involve, in different ways and to varying degrees, a scientific dimension. These are: 1) adventure and exploration tourism with a scientific dimension; 2) Cultural Tourism, such as ecotourism or industrial tourism; 3) scientific eco-volunteering; and 4) scientific research tourism. Following these definitions the article discusses ways and conditions for the appearance of the concept and its importance in contemporary tourism dynamics. The relationship between tourism and science is not an obvious issue for many authors and this article wishes to share ongoing debates and some opposed points of view on the matter.Cet article s’intéresse à la notion de tourisme scientifique. Il propose par une revue de littérature de distinguer quatre formes distinctes de pratiques et de produits touristiques mobilisant de différentes manières et à divers degrés la dimension scientifique. Il s’agit : 1) du tourisme d’exploration et d’aventure à dimension scientifique ; 2) du tourisme culturel proche de l’écotourisme ou du tourisme industriel ; 3) de l’écovolontariat scientifique ; et 4) du tourisme de recherche scientifique.Il discute ensuite les conditions d’émergence de la notion et de sa pertinence dans les dynamiques du tourisme contemporain. Le lien entre tourisme et sciences n’allant pas de soi pour de nombreux auteurs, cette contribution tend à rendre compte des débats et des points de vue parfois contradictoires

Complete and incomplete spin transitions in 1D chain iron(II) compounds.

The synthesis and characterisation of two new octahedral iron(II) SCO coordination polymers [FeL1(bimm)] (1) and [FeL2(bppa)](MeOH)0.5 (2) (L1 = [3,30]-[1,2- phenylenebis-(iminomethylidyne)bis(4-phenyl-,4-butanedionato)(2-)-N,N0,O2,O20], L2 = [E,E]-[{diethyl 2,20-1,2- phenylenebis(iminomethylidyne)bis(3-oxo-3-phenylpropanato)}(2-)-N,N0,O3,O30], bimm = bis(1H-imidazol-1-yl)methane and bppa = 1,3-bis(pyridine-4-yl)propane) is presented. Results from X-ray structure analysis at different temperatures revealed in the case of 1 that the transition from a gradual to a cooperative SCO with a 5 K wide hysteresis is due to an increase of the short intermolecular contacts, which exceed a certain threshold for the cooperative effect. In the case of compound 2 an incomplete spin transition with a 4 K wide hysteresis was observed. The low temperature wMT product remains constant at a value typical for a mixed HS/LS state in stepwise spin transitions. A quantitative correlation between the cooperative effects of 12 monomer and polymer iron(II) SCO complexes and their structural properties derived from X-ray structure analysis, the so-called crystal contact index, CCI, is introduced

Le tourisme scientifique : un essai de définition

International audienceThis article focuses on the notion of scientific tourism. It offers through a literary review to distinguish four distinct forms, practices and related tourism products, that involve, in different ways and to varying degrees, a scientific dimension. These are: 1) adventure and exploration tourism with a scientific dimension; 2) Cultural Tourism, such as ecotourism or industrial tourism; 3) scientific eco-volunteering; and 4) scientific research tourism. Following these definitions the article discusses ways and conditions for the appearance of the concept and its importance in contemporary tourism dynamics. The relationship between tourism and science is not an obvious issue for many authors and this article wishes to share ongoing debates and some opposed points of view on the matter.Cet article s’intéresse à la notion de tourisme scientifique. Il propose par une revue de littérature de distinguer quatre formes distinctes de pratiques et de produits touristiques mobilisant de différentes manières et à divers degrés la dimension scientifique. Il s’agit : 1) du tourisme d’exploration et d’aventure à dimension scientifique ; 2) du tourisme culturel proche de l’écotourisme ou du tourisme industriel ; 3) de l’écovolontariat scientifique ; et 4) du tourisme de recherche scientifique.Il discute ensuite les conditions d’émergence de la notion et de sa pertinence dans les dynamiques du tourisme contemporain. Le lien entre tourisme et sciences n’allant pas de soi pour de nombreux auteurs, cette contribution tend à rendre compte des débats et des points de vue parfois contradictoires