Search results for "MBL"
showing 10 items of 1636 documents
Self-Assembly of Water-Mediated Supramolecular Cationic Archimedean Solids
2013
Understanding the self-assembly of small structural units into large supramolecular assemblies remains one of the great challenges in structural chemistry. We have discovered that tetrahedral supramolecular cages, exhibiting the shapes of Archimedean solids, can be self-assembled by hydrogen bonding interactions using tricationic N-donors (1 or 2) in cooperation with water (W). Single crystal X-ray analysis shows that cage (2)4(W)6, assembled in an aqueous solution of cation 2 and KPF6, consists of four tripodal trications linked by six water monomers and resembles the shape of a truncated tetrahedron. Similarly, cage (1)4(W6)4 spontaneously self-assembles in an aqueous solution of cation 1…
[2]Catenanes and inclusion complexes derived from self-assembled rectangular PdII and PtII metallocycles
2012
New inclusion complexes and [2]catenanes were self-assembled from a fluorescent diazapyrenium based ligand, a PdII or PtII complex, and cyclic or acyclic electron rich aromatic guests in aqueous and organic media. The molecular rectangles display a π-deficient cavity suitable to incorporate π-donor aromatic systems. The inclusion complexes between the metallocycles and phenylenic (2a,b) and naphthalenic (3a,b–5a,b) derivatives were studied by NMR, UV-vis and fluorescence spectroscopy. The crystal structure of (3b) ⊂ 1a·6PF(6) confirmed the insertion of the guest into the cavity of the metallocycle. Following the same self-assembly strategy, the use of polyethers 6,7 as π-donors resulted in …
Complexation and Extraction of PAHs to the Aqueous Phase with a Dinuclear Pt II Diazapyrenium‐Based Metallacycle
2010
New palladium and platinum metallacycles have been synthesized by reaction between a 2,7-diazapyrenium-based ligand and Pd(II) and Pt(II) complexes. The inclusion complexes between the metallacycles and polycyclic aromatic hydrocarbons (PAHs) in CD(3)NO(2) and D(2)O were studied by NMR spectroscopy. The structures of the inclusion complexes of the Pt metallacycle as host with pyrene, phenanthrene, and triphenylene were confirmed by single crystal X-ray crystallography. The association constants between the Pt metallacycle and the selected PAHs were determined in CH(3)CN following the characteristic charge-transfer band displayed in their UV/Vis absorption spectrum. Although in aqueous solut…
Functionalization of Crosslinked Vesicles by Co-Self-Assembly of a Gelable Diblock Copolymer and Mercaptosilane
2008
Herein, a convenient and general method to simultaneously fix and functionalize polymeric vesicles with sulphydryl groups by the co-self-assembly of poly(ethylene oxide)-block-poly[3-(triethoxysilyl)propyl methacrylate] (PEO-b-PTESPMA) and 3-mercaptopropyltrialkoxysilane in an aqueous solution is reported. The presence of sulphydryl groups across the vesicle membrane has been confirmed by using an energy-filtered technique during TEM analysis and by capturing Au nanoparticles.
NEW GRAFT COPOLYMERS OF HYALURONIC ACID AND POLYLACTIC ACID: SYNTHESIS AND CHARACTERIZATION
2006
Abstract New graft copolymers have been synthesized, using hyaluronic acid (HA) as a hydrophilic backbone and polylactic acid (PLA) as an aliphatic polyester in order to obtain new polymeric derivatives of HA able to hydrophobically associate in an aqueous medium. Hyaluronic acid with low molecular weight was made soluble in organic solvent by transformation to its tetrabutylammonium (TBA) salt. Using the HA–TBA derivative, the reaction was performed in dimethylsulfoxide adding as a reagent the N -hydroxysuccinimide derivative of PLA. Two HA–PLA graft copolymers have been synthesized and characterized by FT-IR, 1 H NMR spectroscopy and gel permeation chromatography. The interaction between …
Experimental virus evolution reveals a role of plant microtubule dynamics and TORTIFOLIA1/SPIRAL2 in RNA trafficking.
2014
1 tabla y 2 figuras
Early Bronze Age painted wares from Tell el-'Abd, Syria: A compositional and technological study
2018
Abstract The ‘Euphrates Monochrome Painted Ware’ (henceforth EMPW) is a ceramic style attested in the Middle Euphrates region in northern Syria at the beginning of the Early Bronze Age, ca. 2900–2700 BCE. This style is not an isolated phenomenon; rather, it must be understood in the context of a general, albeit short-lived, re-introduction of painted ceramics into local assemblages of Greater Mesopotamia. In the present study, we investigate the technology and provenance of the painted pottery from Tell el-'Abd (North Syria) and its relation to contemporary ceramics retrieved at this site. We apply a combination of macroscopic observations, ceramic petrography, and micro X-ray diffraction (…
on the contrasts in the charcoal assemblage of a Late Iron Age and a Romano-British roadside settlement
2019
On the contrasts in the charcoal assemblage of a Late Iron Age and a Romano-British roadside settlement
Preservation and decay of plant remains in two Palaeolithic sites: Abrigo de la Quebrada and Cova de les Cendres (Eastern Spain). What information ca…
2020
Abstract Plant remains are quickly affected by post-depositional processes once they are deposited in archaeological sites. In normal conditions, decomposing organisms cause their decay and final disappearance unless a preservation agent, as carbonisation or mineralisation, inhibit their activity. Moreover, physical and chemical processes could also lead to the partial or total destruction of the archaeobotanical assemblage. Thus, an analysis of their characteristics is useful for an assessing of the taphonomic processes. Archaeobotanical assemblages from two Palaeolithic sites, Abrigo de la Quebrada and Cova de les Cendres, have been analysed in terms of taxonomic composition of the assemb…