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5 results on '"Marchió L"'

2. Flexible porous molecular materials responsive to CO2, CH4 and Xe stimuli

Author

Bassanetti, I, Bracco, S, Comotti, A, Negroni, M, Bezuidenhout, C, Canossa, S, Mazzeo, P, Marchió, L, Sozzani, P, Bassanetti, Irene, Bracco, Silvia, Comotti, Angiolina, Negroni, Mattia, Bezuidenhout, Charl, Canossa, Stefano, Mazzeo, Paolo Pio, Marchió, Luciano, Sozzani, Piero, Bassanetti, I, Bracco, S, Comotti, A, Negroni, M, Bezuidenhout, C, Canossa, S, Mazzeo, P, Marchió, L, Sozzani, P, Bassanetti, Irene, Bracco, Silvia, Comotti, Angiolina, Negroni, Mattia, Bezuidenhout, Charl, Canossa, Stefano, Mazzeo, Paolo Pio, Marchió, Luciano, and Sozzani, Piero

Abstract

In the search for flexible molecular crystals endowed with porosity, we achieved the fabrication of expandable crystalline prototypal structures, which allow the absorption of gases, without modifying the crystal architecture. The design brings together highly symmetrical tetrahedral elements to construct swellable porous adamantoid frameworks through co-operation of eight surrounding hydrogen bonds mounted on conformationally flexible groups. The flexibility of the porous crystals manifests itself in response to stimuli of selected gases, which promote reversible conformational changes, inducing breathing in the molecular structure. The backbone of the reticular construction is based on the formation of the carboxylic dimers, which project outwards from the tetrahedral molecular core to consolidate the 3D framework. Contact with proper gases such as CO2, Xe and hexane triggers a 56-70% enlargement of the channel cross-section. The accommodation of CO2 and Xe in the channel chambers was revealed by synchrotron-light X-ray diffraction, combined with molecular dynamics and density functional theory (DFT) theoretical calculations. Rare experimental observations of xenon dynamics, in which Xe diffuses along the channels and experiences different chamber orientations in the crystal, were gathered by analysing 129Xe NMR chemical shift anisotropy profiles, which encode the shape and orientation of each visited cavity along the channel. The jump rate and activation energy experienced was uniquely established by exploring Xe atoms in their diffusional path. Nitrogen showed a low affinity to the matrix and was unable to enlarge the pores, thus it was excluded from the restrictive pores of the empty crystal. Given the properties of molecular crystals, it is possible to outline some advantageous aspects, such as simple design, easy self-assembly, solubility, reversible gas uptake and absence of metal ions, and they can thus be considered for eco-friendly gas capture and separat

Published
2018

3. Flexible porous molecular materials responsive to CO2, CH4 and Xe stimuli

Author

Angiolina Comotti, Stefano Canossa, Charl X. Bezuidenhout, M Negroni, Luciano Marchiò, Paolo Pio Mazzeo, Piero Sozzani, Irene Bassanetti, Silvia Bracco, Bassanetti, I, Bracco, S, Comotti, A, Negroni, M, Bezuidenhout, C, Canossa, S, Mazzeo, P, Marchió, L, and Sozzani, P

Subjects
Materials science, solid state NMR of CO2, Xe NMR, chemistry.chemical_element, 02 engineering and technology, CHIM/04 - CHIMICA INDUSTRIALE, 010402 general chemistry, 01 natural sciences, Crystal, Molecular dynamics, Xenon, molecular crystal, Molecule, General Materials Science, Anisotropy, hydrogen bond, Renewable Energy, Sustainability and the Environment, Hydrogen bond, General Chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, CHIM/02 - CHIMICA FISICA, chemistry, Chemical physics, flexible porous material, Density functional theory, Absorption (chemistry), 0210 nano-technology
Abstract

In the search for flexible molecular crystals endowed with porosity, we achieved the fabrication of expandable crystalline prototypal structures, which allow the absorption of gases, without modifying the crystal architecture. The design brings together highly symmetrical tetrahedral elements to construct swellable porous adamantoid frameworks through co-operation of eight surrounding hydrogen bonds mounted on conformationally flexible groups. The flexibility of the porous crystals manifests itself in response to stimuli of selected gases, which promote reversible conformational changes, inducing breathing in the molecular structure. The backbone of the reticular construction is based on the formation of the carboxylic dimers, which project outwards from the tetrahedral molecular core to consolidate the 3D framework. Contact with proper gases such as CO2, Xe and hexane triggers a 56-70% enlargement of the channel cross-section. The accommodation of CO2 and Xe in the channel chambers was revealed by synchrotron-light X-ray diffraction, combined with molecular dynamics and density functional theory (DFT) theoretical calculations. Rare experimental observations of xenon dynamics, in which Xe diffuses along the channels and experiences different chamber orientations in the crystal, were gathered by analysing 129Xe NMR chemical shift anisotropy profiles, which encode the shape and orientation of each visited cavity along the channel. The jump rate and activation energy experienced was uniquely established by exploring Xe atoms in their diffusional path. Nitrogen showed a low affinity to the matrix and was unable to enlarge the pores, thus it was excluded from the restrictive pores of the empty crystal. Given the properties of molecular crystals, it is possible to outline some advantageous aspects, such as simple design, easy self-assembly, solubility, reversible gas uptake and absence of metal ions, and they can thus be considered for eco-friendly gas capture and separation.

Published
2018
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4. 1,2,4-Triazolyl 5-Azaspiro[2.4]heptanes: Lead Identification and Early Lead Optimization of a New Series of Potent and Selective Dopamine D3 Receptor Antagonists.

Author

Micheli F, Bacchi A, Braggio S, Castelletti L, Cavallini P, Cavanni P, Cremonesi S, Dal Cin M, Feriani A, Gehanne S, Kajbaf M, Marchió L, Nola S, Oliosi B, Pellacani A, Perdonà E, Sava A, Semeraro T, Tarsi L, Tomelleri S, Wong A, Visentini F, Zonzini L, and Heidbreder C

Subjects
Animals, CHO Cells, Cricetulus, Crystallography, X-Ray, Ether-A-Go-Go Potassium Channels metabolism, Humans, Models, Molecular, Receptors, Dopamine D3 metabolism, Structure-Activity Relationship, Triazoles chemistry, Triazoles pharmacology, Heptanes chemistry, Heptanes pharmacology, Receptors, Dopamine D3 antagonists & inhibitors, Spiro Compounds chemistry, Spiro Compounds pharmacology
Abstract

A novel series of 1,2,4-triazolyl 5-azaspiro[2.4]heptanes with high affinity and selectivity at the dopamine (DA) D3 receptor (D3R) is described. Some of these compounds also have high selectivity over the hERG channel and were characterized with respect to their pharmacokinetic properties both in vitro and in vivo during lead identification and early lead optimization phases. A few derivatives with overall favorable developability characteristics were selected for further late lead optimization studies.

Published
2016
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5. Synthesis and characterization of silver(I) pyrazolylmethylpyridine complexes and their implementation as metallic silver thin film precursors.

Author

Bassanetti I, Twist CP, Kim MG, Seyam AM, Bazzi HS, Wang QJ, Chung YW, Marchió L, Delferro M, and Marks TJ

Subjects
Crystallography, X-Ray, Microscopy, Electron, Scanning, Models, Molecular, Proton Magnetic Resonance Spectroscopy, Pyridines chemistry, Silver Compounds chemistry, Spectrometry, Mass, Electrospray Ionization, Pyridines chemical synthesis, Silver Compounds chemical synthesis
Abstract

A series of light- and air-stable silver(I) pyrazolylmethylpyridine complexes [Ag(L(R))]n(BF4)n (L = pyrazolylmethylpyridine; R = H, 1; R = Me, 2; R = i-Pr, 3) and [Ag(L(R))(NO3)]2 (L = pyrazolylmethylpyridine; R = H, 4; R = Me, 5; R = i-Pr, 6) has been synthesized and structurally and spectroscopically characterized. In all of the molecular structures, the pyrazolylmethylpyridine ligands bridge two metal centers, thus giving rise to dinuclear (2, 4, 5, and 6) or polynuclear structures (1 and 3). The role played by the counteranions is also of relevance, because dimeric structures are invariably obtained with NO3(-) (4, 5, and 6), whereas the less-coordinating BF4(-) counteranion affords polymeric structures (1 and 3). Also, through atoms-in-molecules (AIM) analysis of the electron density, an argentophilic Ag···Ag interaction is found in complexes 2 and 4. Thermogravimetric analysis (TGA) shows that the thermolytic properties of the present complexes can be significantly modified by altering the ligand structure and counteranion. These complexes were further investigated as thin silver film precursors by spin-coating solutions, followed by annealing at 310 °C on 52100 steel substrates. The resulting polycrystalline cubic-phase Ag films of ∼55 nm thickness exhibit low levels of extraneous element contamination by X-ray photoelectron spectroscopy (XPS). Atomic force microscopy (AFM) and scanning electron microscopy (SEM) indicate that film growth proceeds primarily via an island growth (Volmer-Weber) mechanism. Complex 4 was also evaluated as a lubricant additive in ball-on-disk tribological tests. The results of the friction evaluation and wear measurements indicate a significant reduction in wear (∼ 88%) at optimized Ag complex concentrations with little change in friction. The enhanced wear performance is attributed to facile shearing of Ag metal in the contact region, resulting from thermolysis of the silver complexes, and is confirmed by energy-dispersive X-ray analysis of the resulting wear scars.

Published
2014
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