Search results for "toluene"

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…

Alkoxo, chlorido, and methyl derivatives of oxidomolybdenum(VI) complexes with tetradentate [O3N]-type ligands

2007

Dioxomolybdenum(VI) complex [MoO 2 (Heg) 2 ] (H 2 eg = 1,2-ethanediol) reacts with phenolic ligand precursors tris(2-hydroxy-3,5-dimethylbenzyl)amine (H 3 L Me ) and tris(2-hydroxy-3,5-di- tert -butylbenzyl)amine (H 3 L t Bu ) to form oxomolybdenum(VI) complexes of type [MoO(L R ) (Heg)]. The Heg ligand can be replaced by other alcohols (i.e. 2-aminoethanol, 2-amino-2-methylpropan-1-ol, 2-(dimethylamino)ethanol or allyl alcohol) in the reaction at refluxing toluene or at neat alcohol. Treatment of [MoO(L R )(Heg)] with Me 3 SiCl yields corresponding chlorido complexes [MoO(L R )Cl]. These are also formed in the reaction of H 3 L R with [MoO 2 Cl 2 (dmf) 2 ]. The reaction of [MoO(L R )Cl] wi…

Reaction of Tris(2-thienyl)phosphine with Dirhodium(II) Acetate. Orthometalation of a Heteroaromatic π-System and an Unusual Ring Rearrangement

2003

The reaction of tris (2-thienyl)phosphine (1) with dirhodium(II) acetate in a 9:1 refluxing toluene/ acetic acid mixture for 2 h leads to the formation of two metalated compounds. The structure of one of them contained two new orthometalated phosphines in a head-to-head arrangement, and, surprisingly, the metalated thiophene rings, but not the nonmetalated ones, were rearranged to a 3-thienyl structure. Both types of dirhodium compounds were assessed in a catalytic α-diazo ester transformation.

Synergistic Interactions between Vitamin A and Vitamin E against Lipid Peroxidation in Phosphatidylcholine Liposomes

1996

Interactions between alpha-tocopherol and all-trans retinol in suppressing lipid peroxidation were studied in a unilamellar liposomal system of phosphatidylcholine from either egg or soybean, in which peroxidation was initiated by the water-soluble azo initiator 2,2-azobis(2-amidino-propane)hydrochloride and peroxidation was measured as production of conjugated diene hydroperoxides. While all-trans retinol alone was poorly effective, the combination of all-trans retinol with alpha-tocopherol caused an inhibition period far beyond the sum of the inhibition periods observed with individual antioxidants, providing evidence of synergistic interactions. Furthermore, the inhibition rate calculate…

Microwave-based gas sensor with phthalocyanine film at room temperature

2013

Abstract This work presents the development of a microwave gas sensor at room temperature. The design of the sensor includes a coplanar grounded wave guide where is deposited a molecular gas sensing material. In this study, the sensitive material is a thin layer of cobalt phthalocyanine (CoPc), sensitive to ammonia and toluene. Submitted to an electromagnetic incident wave in the microwave range, the sensor response is a reflected wave. In the presence of pollutant, the reflected wave shape is specific to the species concentrations. The results interpretation is led at each frequency by the evaluation of the reflected coefficient, which traduces the ratio between the reflected wave over the…

Experimental and Theoretical Investigations on the Synthesis, Structure, Reactivity, and Bonding of the Stannylene-Iron Complex Bis{{bis(2-tert-butyl…

2000

The pi-(arene)bis(stannylene) complex bis(bis(2-tert-butyl-4,5,6-trimethylphenyl)SnFe(eta6-toluene) (Sn-Fe-Sn, 15) is accessible in high yields by a metal-atom-mediated synthesis between iron atoms, toluene, and the stannylene [bis(2-tert-butyl-4,5,6-trimethylphenyl)Sn](3). Complex 15 has a half-sandwich structure with short Fe -Sn bonds (2.432(1) A) and a trigonal-planar coordination at both the Fe and Sn atoms. The distance between the two Sn centers is 3.56 A. Complex 15 is stable under ambient conditions and displays a pi-arene lability, so far rarely observed for (arene)iron complexes; this leads to an irreversible substitution of the arene and formation of fivefold-coordinated zeroval…

Design and synthesis of colloidal nanocrystal heterostructures with tetrapod morphology.

2006

Tuning the Basicity of Synergic Bimetallic Reagents: Switching the Regioselectivity of the Direct Dimetalation of Toluene from 2,5‐ to 3,5‐Positions

2008

Meta-meta metalation: Remarkably, toluene can be directly dimanganated or dimagnesiated at the 3,5-positions using bimetallic bases with active Me3SiCH2 ligands (see scheme, blue). In contrast, n-butyl ligands lead to 2,5-metalation (red). tmp=2,2,6,6-tetramethylpiperidide.

Antioxidant Activity and Release Kinetics of Caffeic and p-Coumaric Acids from Hydrocolloid-Based Active Films for Healthy Packaged Food

2017

International audience; Sustainable hydrocolloid-based films containing natural antioxidants, caffeic and p-coumaric acids at different concentrations of 0.5%, 1%, 5%, and 10% w/w of polymers, were designed for packing fatty foods. Antioxidant activities and kinetics for all film formulations were assessed using radical scavenging activity (DPPH), reducing power, and iron chelating ability. Release kinetics of the antioxidants from the films into a food simulant (96% ethanol) were analyzed. The intermolecular interactions between antioxidants and polymers chains were assessed by Fourier transform infrared attenuated total reflectance (FTIR-ATR) and related to the film properties. Antioxidan…

Lipase-catalyzed resolution of anti-6-substituted 1,3-dioxepan-5-ols

2006

Abstract Several anti-6-substituted 1,3-dioxepan-5-ols were kinetically resolved using an immobilized lipase (Amano PS–C II) in toluene in the presence of vinyl acetate at 30 °C. This approach provided, in some cases, the alcohol and the acetate in high enantiomeric purity, depending on the nature of the substituent (R = N3, SePh, I, OBn) and the acetal group (unsubstituted or dimethyl). The role of the size of substituents is also discussed. Enantiopure anti-6-substituted 1,3-dioxepan-5-ols are useful building blocks.