Search results for "Titan"
showing 10 items of 1109 documents
Optically Active Titanium Complexes Containing Linked Amido‐cyclopentadienyl Ligands: Their Use as Asymmetric Hydrogenation Catalysts
1996
Optically active titanium complexes of the formula Ti(η5:η1−C5R4SiMe2NCHMePh)Cl2 (R = H, Me), containing the cyclopentadienyl ligand linked to a chiral 1-phenylethylamido moiety, were synthesized and characterized in both enantiomerically pure forms. A single-crystal X-ray structural analysis of (S)()Ti(η5:η1−C5H4SiMe2NCHMePh)Cl2 shows a conformation in which the phenyl group is turned away from the metal center. NOE measurements suggest that a related structure is retained in solution. Upon activation with n-butyllithium, these complexes show hydrogenation activity toward imines with slight enantioselectivity.
The Kinetic Stability of Cationic Benzyl Titanium Complexes that Contain a Linked Amido-Cyclopentadienyl Ligand: The Influence of the Amido-Substitue…
2002
Cationic benzyl titanium complexes [Ti(η 5 : η 1 -C 5 Me 4 SiMe 2 NR')-(CH 2 Ph)] + were cleanly formed by the reaction of the dibenzyl titanium complexes [Ti(η 5 : η 1 -C 5 Me 4 SiMe 2 NR')(CH 2 Ph) 2 with B(C 6 F 5 ) 3 and [Ph 3 C][B(C 6 F 5 ) 4 ] in bromobenzene. NMR spectroscopic studies suggest that the benzyl titanium cations contain a fluxional η 2 -coordinated benzyl ligand. Kinetic analysis showed that the benzyl titanium cations decompose according to first-order kinetics and that the amido substituents R' (R' = Me, i Pr, t Bu) in the linked amido-cyclopentadienyl ligand influence the lability of these benzyl titanium cations. The order of the kinetic stability of the benzyl titan…
Titanium and zirconium complexes that contain a tridentate bis(phenolato) ligand of the [OOO]-type
2003
Abstract The oxygen-linked bis(phenol) 2-oxapropanediyl-1,3-bis(2-tert-butyl-4-methylphenol), [OOO]H2, was prepared in good yield by the condensation of 2-tert-butyl-6-hydroxymethyl-4-methylphenol at 155 °C. This bis(phenol) reacted cleanly with titanium tetrachloride to give the orange titanium dichloro complex [OOO]TiCl2 in virtually quantitative yield. The solubility in pentane indicates a monomeric structure for [OOO]TiCl2 in solution. The reaction of titanium tetra(isopropoxide) gave the di(isopropoxy) complex [OOO]Ti(OiPr)2 which also adopts a monomeric structure of C2v-symmetry in solution. The reaction of the dichloro complex [OOO]TiCl2 with benzyl Grignard reagent in diethyl ether …
Linked amido-indenyl complexes of titanium
1996
Abstract Titanium complexes Ti( η 5 : η 1 -C 9 H 6 SiMe 2 NCMe 3 )X 2 (X = Cl, Me, CH 2 SiMe 3 , CH 2 Ph) containing the tert -amino-functionalized indenyl ligand C 9 H 6 SiMe 3 NCMe 3 have been synthesized by the reaction of the dilithium derivative Li 2 [C 9 H 6 SiMe 2 NCMe 3 ] with TiCl 3 (THF) 3 followed by oxidation or by the alkylation of the dichloro derivative. Unexpectedly, the reaction of C 9 H 6 (SiMe 3 )(SiMe 2 Cl) with TiCl 4 does not give Ti( η 5 -C 9 H 6 SiMe 2 Cl)Cl 3 .
Towards a Library of “Early‐Late” Ti–Ru Bimetallic Complexes
2005
A series of new titanocene phosphanes 3–6 have been prepared by replacing both chloride atoms at the titanium atom of the complexes [TiCl2(η5-C5H5){η5-C5H4(CH2)2PR2}] (1: R = Ph; 2: R = Cy) by sodium fluoride or sodium benzoate in two-phase systems. Treatment of these new metalloligands with the binuclear complex [(p-cymene)RuCl2]2 affords the targeted titanocene difluoride and titanocene dibenzoate bimetallic ruthenium complexes 8–11. The first chiral Ti–Ru bimetallic complex 12 bearing a binaphthyloxy ligand at the titanium centre has been synthesised in this way. In each series, an X-ray crystal structure has been determined. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, …
Modeling of an annular photocatalytic reactor for water purification: oxidation of pesticides.
2004
Photocatalytic oxidation (PCO) over titanium dioxide (TiO2) is a “green” sustainable process for the treatment and purification of water and wastewater. However, the application of PCO for wastewater treatment on an industrial scale is currently hindered by a lack of simple mathematical models that can be readily applied to reactor design. Current models are either too simplistic or too rigorous to be useful in photocatalytic reactor design, scale-up, and optimization. In this paper a simple mathematical model is presented for slurry, annular, photocatalytic reactors that still retains the essential elements of a rigorous approach while providing simple solutions. The model extends the appl…
Augstas enerģijas jonizējošā starojuma izraisītu radiācijas defektu analīze litija ortosilikātu un litija metatitanātu saturošos paraugos
2022
Augstas enerģijas jonizējošā starojuma izraisītu radiācijas defektu analīze litija ortosilikātu un litija metatitanātu saturošos paraugos. Tomele M., zinātniskais vadītājs: vadošais pētnieks, Dr. chem. Zariņš A., konsultanti: vadošā pētniece, Dr. chem. Ķizāne G., zin. asist., Bc. chem. Seņko M. Bakalaura darbs, 49 lappuses, 24 attēli, 7 tabulas, 91 literatūras avots, 5 pielikumi. Latviešu valodā. Litija ortosilikāts (Li4SiO4) un litija metatitanāts (Li2TiO3) ir perspektīvi materiāli tritija ģenerēšanai kodoltermiskās sintēzes reaktoros, to ekspluatācijas laikā materiāli būs pakļauti jonizējošā starojuma ietekmei. Darba mērķis ir analizēt radiācijas defektu veidošanos ar augstas enerģijas jo…
Tunable light emission by exciplex state formation between hybrid halide perovskite and core/shell quantum dots: Implications in advanced LEDs and ph…
2016
A perovskite–quantum dot exciplex has been detected, opening a broad range of possibilities for advanced optoelectronic devices.
The titanium-made growth-guidance technique for early-onset scoliosis at minimum 2-year follow-up: A prospective multicenter study.
2019
Background The management of early-onset scoliosis (EOS) remains a serious challenge in pediatric orthopedics. The growth-guidance system (GGS) is a surgical option that allows continuous growth along a rod, averting the need for repeated operative lengthening. Objectives The objective of this study was to evaluate the outcomes of the GGS in the treatment of EOS. Material and methods A prospective study, including 81 patients from 4 departments treated with this method from 2013 to 2015, was conducted with a minimum follow-up period of 24 months. The follow-up data of 57 patients was available, thus the drop-out rate was 29.63%. There were 44 girls with a mean age of 10.03 years and 13 boys…
Scandium(III) complexes of monophosphorus acid DOTA analogues: a thermodynamic and radiolabelling study with 44 Sc from cyclotron and from a 44 Ti/ 4…
2015
International audience; The complexation ability of DOTA analogs bearing one methylenephosphonic (DO3AP) or methylene-phosphinic (DO3AP PrA and DO3AP ABn) acid pendant arm toward scandium was evaluated. Stability constants of their scandium(III) complexes were determined by potentiometry combined with 45 Sc NMR spectroscopy. The stability constants of the monophosphinate analogues are somewhat lower than that of the Sc–DOTA complex. The phosphorus acid moiety interacts with trivalent scandium even in very acidic solutions forming out-of-cage complexes; the strong affinity of the phosphonate group to Sc(III) precludes stability constant determination of the Sc–DO3AP complex. These results we…