Search results for "Titanium"

Zirconium dioxide implants as an alternative to titanium: A systematic review

2020

Background: This systematic review evaluates the available scientific literature to demonstrate the aesthetic and clinical benefits and to determine the survival and the success of zirconium dioxide implants concerning titanium implants. Material and Methods: The electronic databases were searched until January 2020. Outcome measures were pink aesthetic score (PAS), white aesthetic score (WAS), bleeding on probing (BOP) and probing depth (PD). The addressed PICO question was: In partially edentulous patients in the upper-anterior sector, do zirconium dioxide implants provide aesthetic benefits over conventional titanium implants? Results: In the 15 articles included after the screening were…

Effect of bone loss on the fracture resistance of narrow dental implants after implantoplasty. An in vitro study

2021

Background Implantoplasty (IP) involves polishing of the exposed surface of implants affected by peri-implantitis (PI). A study was made to determine whether the degree of bone loss influences the fracture resistance of implants with or without IP. Material and Methods An in vitro study was carried out on 32 narrow (3.5 mm) dental implants with a rough surface and external hexagonal connection. Implantoplasty was performed in half of the implants of the sample. Both the IP and control implants were divided into two subgroups according to the amount of bone loss (3 mm or 7.5 mm). Standardized radiographic assessment of implant width was performed using specific software. The main outcome var…

Synthesis and structural characterization of novel tetranuclear organotitanoxane derivatives.

2011

Synthesis of the novel titanoxane compounds, [(TiCl)(TiOH){(Ti)[μ-(η(5)-C(5)Me(4)SiMe(2)O-κO)](2)(μ-O)}(2)(μ-O)] (4) and [{Ti[μ-(η(5)-C(5)Me(4)SiMe(2)O-κO)](μ-O)}(4)] (5) by controlled reaction of the dinuclear titanium oxo complex [{Ti{μ-(η(5)-C(5)Me(4)SiMe(2)O-κO)}Cl](2)(μ-O)] (1) with 2 equiv of LiOH is reported. Complex 4 is innovative and remarkable. It is one of the rare known examples of tetranuclear stable terminal hydroxo titanium complexes, with an open-chained structure, which coincides with the transient metal monohydroxo proposed in the stepwise pathway employed to justify the formation of the hexanuclear complex [{Ti[μ-(η(5)-C(5)Me(4)SiMe(2)O-κO)](μ-O)}(6)] (3) from 1. (1)H DO…

Surface Chemistry Directs the Tunable Assembly of TiO 2 Anatase Nanocubes into Three‐Dimensional Mesocrystals

2019

Expanding the Size of Catecholesters - Modified Ligands for the Hierarchical Assembly of Dinuclear Titanium(IV) Helicates

2015

Five 2,3-dihydroxybenzoic acid derivatives 1 – 5 were used as starting materials to obtain the corresponding methyl and ethyl esters. Those were applied as ligands in the hierarchical self-assembly of lithium-bridged dinuclear titanium(IV) complexes 1a–4a, 1b–3b, and 5b. The equilibria between the mononuclear triscatecholate complexes (monomer) and the dinuclear helicates (dimer) were observed by 1H NMR spectroscopy in [D6]DMSO and [D4]MeOH at room temperature.

Herstellung von 1,5‐Cyclooctadiin und 1,3,5,7‐Cyclooctatetraen aus 1,5‐Cyclooctadien

1994

Preparation of 1,5-Cyclooctadiyne and 1,3,5,7-Cyclooctatetraene from 1,5-Cyclooctadiene Bromination of 1,5-cyclooctadiene (1) and stepwise dehydro-bromination first with KOtBu and then with KOtBu/18-crown-6 yields 1,5-cyclooctadiyne (5). A prolonged interaction of the base causes a complete transformation to cyclooc-tatetraene (6). Diyne 5 and even more the intermediate enyne 4 are highly reactive dienophiles. The cycloadducts 10–14 formed with 1,3-cyclohexadiene, carbon disulfide, and tetraphenylcyclopentadienone were isolated and characterized. Treatment of 5 with titanium tetrachloride induces a vigorous polymerization.

Stable Methylene- and Oxo-Bridged Monocyclopentadienyl Titanium Compounds. Molecular Structure of {Ti[μ-(η5-C5Me4SiMe2-O)]Me}2(μ-CH2)

2004

Thermolysis of {Ti[μ-(η5-C5Me4SiMe2-O)]Me2}2 affords the methylene-bridged titanium compound {Ti[μ-(η5-C5Me4SiMe2-O)]Me}2(μ-CH2), concurrent with the evolution of methane, the first example of a fu...

First Titanium-Catalyzed anti-1,4-Hydrosilylation of Dienes

2005

1,4-Hydrosilylation of dienes catalyzed by late transition metals constitutes a straightforward access to allylsilanes. However, when unsymmetric dienes are used, it generally leads to a mixture of regioisomers (tail or head products) via Z-specific 1,4-addition. Here we describe the first catalytic anti-1,4-hydrosilylation of dienes using the cheap and stable Cp2TiF2 complex as catalyst. It affords E-allylsilanes in good to excellent yields with an unprecedented regio- and diastereoselectivity. Dehydrogenative double silylation of dienes can be selectively obtained by simply changing the activation protocol of the precatalyst.

Edited by Ilan Marek: Titanium and zirconium in organic synthesis. Wiley-VCH, Weinheim, 2002. xxv?+?512 pp. Price �95.00. ISBN 3-527-30428-2

2002

Homo- and Heterometallic Aluminum and Titanium Complexes of Tridentate (OSO) Ligand:  Synthesis, Structure, and Catalytic Activity

2005

The tridentate (OSO-functions) biphenol, 2,2‘-thiobis{4-(1,1,3,3-tetramethylbutyl)phenol} (tbopH2), reacts with AlMe3 to give [Al2(μ-tbop-κ3O,S,O)2Me2] (1). Alcoholysis of 1 results in the formation of [Al2(μ-OEt)2(tbop-κ3O,S,O)2] (2). The reaction of 2 with TiCl4 gives the trimeric complex [Ti3(μ-OEt)2(μ-tbop-κ3O,S,O)2Cl6] (3)·C6H14. Alkylation of 3·C6H14 with LiMe produces two dimeric complexes, [Ti2(μ-tbop-κ3O,S,O)2Me4] (4) and [Ti2(μ-OE)2(tbop-κ3O,S,O)2Me2] (5)·Et2O. Treatment of [Ti2(μ-OEt)2(tbop-κ3O,S,O)2(OEt)2] with AlMe3 and EtOH afforded the heterobimetallic species, [Ti2Al2(μ-OEt)6(μ-tbop-κ3O,S,O)2(OEt)4] (6). The structures of 1−6 were confirmed by NMR spectroscopy; complexes 1, …