Le bois d'oeuvre et le port de Montréal, 1830-1870 : une approche dendroarchéologique

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Au large de Fermanville – Site de Biéroc-la-Mondrée (EA 2344)

Le site, qui s’implante au pied de la falaise à Biéroc-la-Mondrée près de Fermanville, gît à 20 m de profondeur et serait antérieur au dernier âge glaciaire entre 40 000 à 70 000 ans. Les fouilles menées dans les années 1970 ont permis la découverte de plus de 2 500 silex taillés, dont la majorité sont des produits de débitage où la méthode Levallois apparaît fort bien exprimée. Ces artefacts attestent d’une occupation néandertalienne sur le plateau continental durant le dernier interglaciair..

Inter­calated brucite-type layered cobalt(II) hydroxy­sulfate

In an attempt to synthesize new cobalt(II) sulfate framework structures using 1,4-diaza­bicyclo­[2.2.2]octane as a template, crystals of poly[0.35-[hexa­aqua­cobalt(II)] [tri-μ-hydroxido-μ-sulfato-dicobalt(II)]], {[Co(H2O)6]0.35[Co2(OH)3(SO4)]}n, were obtained as a mixture with [Co(H2O)6]SO4 crystals. The crystal structure can be described as being constructed from discrete brucite-type [Co4(OH)6(SO4)2] layers, each of which is built up from edge-shared [Co(OH)6] and [Co(OH)4(OSO3)2] octa­hedra, with partial inter­calation by [Co(H2O)6]2+ ions. The absence of ca 30% of the [Co(H2O)6]2+ cations indicates partial oxidation of cobalt(II) to cobalt(III) within the layer

Immobilization, Trapping, and Anion Exchange of Perrhenate Ion Using Copper-Based Tripodal Complexes

We describe a multidentate tripodal ligand in which three pendant arms carrying di(2-picolyl)amine units are linked to the ortho positions of a tris(o-xylyl) scaffold, providing N(CH[subscript 2]-o-C[subscript 6]H[subscript 4]CH[subscript 2]N(CH2py)[subscript 2])[subscript 3] (L). Reaction of L with CuCl[subscript 2] in the presence of hexafluorophosphate anion afforded blue cubes of [(CuCl)[subscript 3]L](PF[subscript 6])[subscript 3]·5H[subscript 2]O (1). Crystallographic studies of 1 revealed that the three symmetry-related arms each coordinate a {Cu[superscript II]Cl} unit, and two molecules of 1 are connected to one another through a Cu(μ-Cl)[subscript 2]Cu bridge, extending the molecular structure to form a two-dimensional (2-D) layer. These 2-D layers pack in an ABCABC... fashion with PF[subscript 6]– anions located in between. Reaction of 1 with a stoichiometric amount of perrhenate ion afforded blue plates of [(CuCl)[subscript 3]L](PF[subscript 6])(ReO[subscript 4])[subscript 2]·3H[subscript 2]O (2). Compound 2 has the same lattice structure as 1, but the tricopper unit backbone now traps one ReO[subscript 4]– anion through Coulombic interactions. In addition, three molecules of 2 are bridged by a perrhenate ion, forming a Cu[subscript 3](μ[superscript 3]-ReO[subscript 4]) cluster, to give a different 2-D structure displaying a rare tridentate bridging ReO[subscript 4]– mode. Thus, in addition to classic perrhenate trapping through weak Coulombic interactions, 2 represents an exceptional example in which the ReO[subscript 4]– anion is immobilized in an extended framework through tight covalent interactions. The interlamellar PF[subscript 6]– anions in 1 can be exchanged with other anions including perrhenate, perchlorate, or periodate. The structural similarity between perrhenate and pertechnetate makes these materials of potential interest for pertechnetate trapping

Synthesis and Characterisation of a New Anion Exchangeable Layered Hydroxyiodide

Lu4O(OH)9I·3H2O is a new member of the anion exchangeable lanthanide hydroxyanion family of materials which has been synthesised hydrothermally. Its structure comprises positively charged [Lu4O(OH)9(H2O)3]+ layers with exchangeable charge balancing iodide anions located in the interlayer gallery. It has been found to undergo facile anion exchange reactions with dicarboxylate anions such as succinate and terephthalate at room temperature but reacts less readily with disulfonate anions such as 1,5- and 2,6-naphthalenedisulfonate under the same conditions. At reaction temperatures above 200 °C the cationic inorganic framework Lu3O(OH)6I·2H2O forms instead of the layered phase

Reverse microemulsion synthesis of layered gadolinium hydroxide

A reverse microemulsion approach has been explored for the synthesis of layered gadolinium hydroxide (LGdH) nanoparticles in this work. This method uses oleylamine as a multifunctional agent, acting as surfactant, oil phase and base. 1-butanol is additionally used as a co-surfactant. A systematic study of the key reaction parameters was undertaken, including the volume ratio of surfactant (oleylamine) to water, the reaction time, synthesis temperature, and the amount of co-surfactant (1-butanol) added. It proved possible to obtain pristine LGdH materials at temperatures of 120 °C or below with an oleylamine: water ratio of 1:4. Using larger amounts of surfactant or higher temperatures caused the formation of Gd(OH)3, either as the sole product or as a major impurity phase. The LGdH particles produced have sizes of ca. 200 nm, with this size being largely independent of temperature or reaction time. Adjusting the amount of 1-butanol co-surfactant added permits the size to be varied between 200 and 300 nm