Search results for "Titan"
showing 10 items of 1109 documents
Synthesis and structural characterization of titanium complexes containing a sulfinyl-bridged bis(phenolato) ligand
1998
Abstract Titanium complexes containing the novel tridentate 2,2′-sulfinylbis(6-tert-butyl-4-methylphenoxo) ligand (sibmp) were synthesized and characterized. Treatment of titanium tetra-iso-propoxide with 2,2′-sulfinylbis(6-tert-4-methylphenol) (sibmpH2) in 1:1 molar ratio afforded red-orange, sparingly soluble di-iso-propoxo derivative [Ti(sibmp)(O-i-Pr)2]2·0.5 Et2O. The single-crystal structure analysis was performed and revealed a dimeric centrosymmetric structure with a planar Ti2O2 core. The titanium center is approximately octahedral with a SO function intramolecularly coordinated at the titanium center. Treatment of sibmpH2 with titanium tetra-iso-propoxide in 2:1 molar ratio gave y…
Syntheses and properties of some exo,exo-bis(isodicyclopentadienyl)titanium low-valent complexes
2002
Abstract The paramagnetic compounds exo,exo-bis(η5-isodicyclopentadienyl)chlorotitanium(III) (3) and its analogue with trimethylsilyl-substituted isodicyclopentadienide (isodiCp) ligand (4), and the similar pair of diamagnetic exo,exo-bis(isodicyclopentadienyl)[η2-bis(trimethylsilyl)ethyne]titanium(II) complexes 5 and 6 were obtained by common reduction procedures from exo,exo-bis(isodicyclopentadienyl)titanium(IV) dichloride (1) and exo,exo-bis[η5-2-(trimethylsilyl)isodicyclopentadienyl]titanium(IV) dichloride (2), respectively. As indicated by ESR spectroscopy compound 3 is a dimer in the solid state and in frozen toluene glass but monomeric in toluene solution. Compound 4 is monomeric in…
Crystal structure of μ-oxido-1,1′κ2 O:O-bis{tetra-μ-oxido-1:2κ2 O:O;1:3κ2 O:O;2:3κ4 O:O-tris[1,2,3(η5)-pentamethylcyclopentadienyl]-trianglo-tri…
2015
The title polynuclear organometallic titanium(IV) oxide, [{Ti3(η5-C5Me5)3(μ-O)4}2(μ-O)], exhibits two Ti3O4 cores bridged by an O atom located on a twofold axis. All metal centers present the typical three-legged piano-stool coordination environment, where one site is occupied by a pentamethylcyclopentadienyl ligand linked in an η5-coordination fashion, while three bridging O atoms fill the other three sites.
On the choice of tool material in friction stir welding of titanium alloys
2012
Analytical methodologies for atomic spectrometric determination of metallic oxides in UV sunscreen creams.
2000
In this study, methodologies for determining titanium oxide, zinc oxide and iron oxide are proposed and assayed in commercial sunscreen products. The proposed methodology for TiO2, determination in sunscreens is based on a microwave-assisted treatment for digesting the organic components in a closed teflon reactor in presence of HNO3 and HCl. Titanium is determined by inductive coupled plasma emission spectrometry (ICP-AES). The proposed methodologies for measuring ZnO and Fe2O3 are based on a sample emulsification in water with a non ionic tensioactive and IBMK, followed by Zn and Fe determination by flame atomic absorption spectrometry (FAAS). The methodologies allow a precise and accurat…
Unraveling the exhumation history of high-pressure ophiolites using magnetite (U-Th-Sm)/He thermochronometry
2020
International audience; Magnetite is a ubiquitous oxide in ultramafic and mafic rocks, which is present in a large range of geological and tectonic settings. In the case of high-pressure ultramafic rocks, exhumation timing is commonly constrained by geochronometers in nearby lithologies. The development of the magnetite (U-Th-Sm)/He method (MgHe) has opened new perspectives to refine the exhumation history of such rocks. However no thermal history has been deduced using MgHe data so far. Here we applied MgHe dating to magnetite from an HP-LT alpine ophiolite body (Rocher Blanc) from the Schistes lustres units (Western Alps, France) where part the P-T-t history is constrained to further refi…
Tri-alkenyl polyhedral oligomeric silsesquioxanes as comonomers and active center modifiers in ethylene copolymerization catalyzed by bis(phenoxy-imi…
2018
Abstract In copolymerization of ethylene (E) with tri-alkenyl-silsesquioxanes (POSS-6-3 and POSS-10-3) were used bis(phenoxy-imine) titanium, zirconium and vanadium catalysts, as well as salen-type vanadium catalysts. There were obtained copolymers with POSS-R-3 units as side branches of polymer chains. The type of employed bis(phenoxy-imine) titanium, zirconium and vanadium catalysts and salen-type catalyst of vanadium determined the copolymer chain termination reactions, as well as the mechanism of modification of the active species by the POSS-R-3 comonomer. POSS-R-3 comonomers caused selective poisoning of bis(phenoxy-imine) zirconium catalyst and they provided protection against tight …
Visible light active self-cleaning materials based on porphyrin-sensitised titanium dioxide
2017
Starting from second half of last century, nanostructured semiconductors have had a crucial function in the material science because of their wide application field going from renewable energy to organic/hybrid electronics up to photocatalysis. Among those materials, titanium dioxide is probably the most used because of some important characteristics like the chemical/mechanical stability, environmental sustainability, its low cost and versatility. Indeed, it has been successfully employed as photo- and electro-active component in electronic devices as well as photocatalytic agent1 in water de-pollution application. Interestingly and importantly together, titanium dioxide may also be applie…
Bach fra le stelle
2014
Il testo costituisce la postfazione del volume di Ramin Bahrami "Il suono dell'Occidente. Le opere musicali che hanno fatto la nostra civiltà" (Mondadori 2014) e prende le mosse dal concetto di "Enciclopedia" per tracciare una riflessione storico-musicologica sulle 14 composizioni che Ramin Bahrami ssume quali imprescindibili punti di riferimento per una visione d'insieme della cultura musicale occidentale: da Monteverdi fino a Schoenberg, passando per Vivaldi, Bach, Wagner, Verdi, Mahler, Rakhmaninov e Stravnsky.
Photocatalysis: a promising route for 21st century organic chemistry
2007
One of the main goals of 21st century chemistry is to replace environmentally hazardous processes with energy efficient routes allowing to totally avoid the use and production of harmful chemicals and to maximise the quantity of raw material that ends up in the final product. Selective photocatalytic conversions will play a major role in this evolution and this account shows how photocatalysis is offering an alternative green route for the production of organics.