Search results for "Titan"
showing 10 items of 1109 documents
A comparative study on the polymerization of 1-octene promoted by vanadium and titanium complexes supported by phenoxyimine and salen type ligands
2013
Polymerizations of 1-octene were carried out in the presence of vanadium and titanium complexes bearing salen-type or phenoxyimine ligands activated with various co-catalysts. Vanadium complexes turned out active only in conjunction with MAO, whereas the titanium ones were active in combination with Al(i-Bu)3/Ph3CB(C6F5)4. The activity of all catalysts was moderate or low and it was dependent on the ligand type: bis(phenoxyimine) complexes were more active than the salen ones. Both vanadium and titanium catalytic systems produced poly(1-octene)s possessing atactic structures with [mmmm] sequences in the range from 12 to 56 % at room temperature. A temperature decrease to 0.5 °C for the reac…
Formation of a micropatterned titania photocatalyst by microcontact printed silicatein on gold surfaces
2012
The enzyme silicatein has been bioengineered to carry a thiol-bearing Au-affinity tag (Cys-tag) for direct immobilization on gold carriers in shortest time without the need for prior surface functionalization. Through microcontact printing, defined silicatein micropatterns were created on gold surfaces, facilitating the subsequent enzymatically controlled synthesis of photocatalytically active TiO(2).
Growth of metal/oxide periodic multilayer : relation between structure and electrical behaviour in systems based on titanium and tungsten
2014
Periodic multilayers have found many applications in the fields of optics, mechanics or electronics. However, few studies focus on the electrical responses of the metal/oxide periodic structures versus temperature. The interest of this work was focused on the characterization of the multilayers and their electrical properties versus temperature. In TiO/Ti/TiO/TiO2 and WO/W/WO/WO3 systems produced by the reactive gas pulsing process, sample structures were established by transmission electron microscopy for sublayers thicknesses between 1.3 and 50.8 nm. Then, this study highlights a modification of conventional electrical behavior versus temperature. An empirical relationship was established…
Ligands hybrides : synthèse et chimie de coordination
2011
This manuscript deals with the synthesis of hybrids ligands and their coordination ability. The first part is dedicated to Cp-imidazole, Cp-imidazolium and Cp-phosphine ligands. Several synthetic routes have been developed to reach these mixed ligands and their coordination chemistry has been studied with titanium. In a second part, a method developed in our laboratory to synthesize phosphine-olefines was applied to obtain a phosphino-diene bearing three potential coordination sites. We have studied the coordination modes of this hybrid ligand using various transition metals and some of the formed complexes were tested in catalysis. In the third part is described the coordination chemistry …
Degradation of 4-nitrophenol (4-NP) using Fe–TiO2 as a heterogeneous photo-Fenton catalyst
2010
Photocatalytic degradation of 4-nitrophenol was investigated using Fe-doped (1, 3, 5 and 8 wt.% Fe) TiO(2) catalysts under UV light irradiation in aqueous dispersions in the presence of H(2)O(2). Photocatalysts with the lowest Fe content (1%) showed a considerably better behavior with respect to the unloaded TiO(2) and the catalysts with higher Fe contents. Photocatalytic degradation was studied under different conditions such as amounts of 1% Fe-TiO(2) catalyst, H(2)O(2) dose and initial pH of 4-NP solution. The results indicated that about 67.53% total organic carbon of a solution containing 20 mg L(-1) 4-NP was removed at pH 6.17 by using 4.9 mM of H(2)O(2) and 0.4 g L(-1) of the catalys…
Ti-based robust MOFs in the combined photocatalytic degradation of emerging organic contaminants.
2022
Photocatalysis process is a promising technology for environmental remediation. In the continuous search of new heterogeneous photocatalysts, metal–organic frameworks (MOFs) have recently emerged as a new type of photoactive materials for water remediation. Particularly, titaniumbased MOFs (Ti-MOFs) are considered one of the most appealing subclass of MOFs due to their promising optoelectronic and photocatalytic properties, high chemical stability, and unique structural features. However, considering the limited information of the reported studies, it is a hard task to determine if real-world water treatment is attainable using Ti-MOF photocatalysts. In this paper, via a screening with seve…
Customized Titanium Lattice Structure in Three-Dimensional Alveolar Defect: An Initial Case Letter
2018
The aim of this initial case report was to provide a new protocol for the clinical application of a patient-specific titanium lattice structure (Yxoss CBR®, ReOSS, Filderstadt, Germany) for customized bone regeneration. To obtain a 3-dimensional reconstruction of a posterior mandible segment in a 61-year-old woman, a patient-specific titanium customized lattice structure was used. As graft material autogenous bone tissue mixed with xenogenic alloplastic material (Bio Oss®, Geistlich Pharma, Wolhusen, Switzerland) was obtained for reconstruction. After a healing period of 6 months, the titanium lattice structure was removed and implant placement (Camlog Screw Line, 3.8/11, Camlog, Wimsheim, …
Photocatalytic degradation of acid blue 80 in aqueous solutions containing TiO2 suspensions.
2001
The photocatalytic degradation of the anthraquinonic dye Acid Blue 80 in aqueous solutions containing TiO2 dispersions has been investigated. The process has been monitored by following either the disappearance of the dye (via HPLC) and the formation of its end-products (via IC, GC, and TOC analysis). Although a relatively fast decolorization of the solutions has been observed, the mineralization is slower, and the presence of residual organic compounds was evidenced even after long term irradiation, confirming the relevant stability of anthraquinone derivatives. The identification of various unstable intermedi ates formed after low irradiation times was performed by HPLC-MS, allowing us to…
Titanium Complexes of Chelating, Dianionic O,S,O‐Bisphenolato Ligands: Syntheses, Characterisation, and Catalytic Activity
2005
Titanium complexes based on 2,2'-thiobis[4-(1,1,3,3-tetramethylbutyl)phenolato] (tbop) are prepared by reaction of TiCl 4 or Ti(NMe 2 ) 4 with the parent biphenol. Three new complexes are reported: [Ti 2 (μ-tbop-κ 3 O,S,O)(μ-tbop-κ 2 O,O)-(tbop-κ 3 O,S,O)Cl 2 ] (1).2CH 3 CN, [Ti 2 (μ-tbop-κ 3 O,S,O) 2 Cl 4 ] (2) and [Ti(tbop-κ 3 O,S,O) 2 ] (3). Substitution of the chlorides in 1 and 2 by 2,6-diisopropylphenolato and imido (NtBu) ligands generates the new compounds [Ti 2 (μ-tbop-κ 3 O,S,O) 2 -Cl 2 (dipp) 2 ] (4).Et 2 O and [Ti 2 (μ-tbop-κ 3 O,S,O) 2 (NtBu) 2 -(NH 2 tBu) 2 ] (5), respectively. Treatment of 5 with crude Me 3 -SiCl, containing Me 3 SiOH, produces [Ti(tbop-κ 3 O,S,O)Cl(O-SiMe 3 …
Adhesion and adaptive response of osteoblastlike cells (SAOS-2) grown on dfferent ti-6al-4v surfaces.
2004
Osteoblastic-like cells (SAOS-2) were seeded on three differently treated surfaces of Ti- 6Al-4V (T1: not treated; T2: chemically treated; T3: electrochemically treated). After 6h, the cells grown on T1 and T2 surfaces showed a typical poligonal morphology, they were strongly adherent to the surface and after 24h-48h they spread and formed a confluent monolayer. On the contrary, cells seeded on T3 showed heterogeneous morphology, decreased adhesion, loss of thin cellular expansions, and showed cellular shrinkage and apoptotic blebbing; only after 48h they were able to attach and form a monolayer after 4 days of seeding. Cell proliferation was significantly lower on T3 than T1 and T2 surface…