Tetrahydrofuran

About: Tetrahydrofuran is a research topic. Over the lifetime, 11778 publications have been published within this topic receiving 158241 citations. The topic is also known as: diethylene oxide & 1,4-epoxybutane.

Actinide Redox-Active Ligand Complexes: Reversible Intramolecular Electron-Transfer in U(dpp-BIAN)2/U(dpp-BIAN)2(THF)

Abstract: Actinide complexes of the redox-active ligand (dpp-BIAN)2− (dpp-BIAN = 1,2-bis(2,6-diisopropylphenylimino)acenaphthylene), U(dpp-BIAN)2 (1), U(dpp-BIAN)2(THF) (1-THF), and Th(dpp-BIAN)2(THF) (2-THF), have been prepared. Solid-state magnetic and single-crystal X-ray data for complex 1 indicate a ground-state UIV−π*4 configuration, whereas a (dpp-BIAN)2−-to-uranium electron transfer occurs for 1-THF, resulting in a UIII−π*3 ground configuration. The solid-state magnetic data also indicate that interconversion between the two forms of the complex is possible, limited only by the ability of tetrahydrofuran (THF) vapor to penetrate the solid upon cooling of the sample. In contrast to those in the solid state, spectroscopic data acquired in THF indicate only the presence of the UIV−π*4 form for 1-THF in solution, evidenced by electronic absorption spectra and by measurement of the solution magnetic moment in THF-d8 using the Evans method. Also reported is the electrochemistry of the complexes collected in CH2Cl...

Selective Extraction of Bio-oil from Hydrothermal Liquefaction of Salix psammophila by Organic Solvents with Different Polarities through Multistep Extraction Separation

Abstract: Bio-oil obtained from hydrothermal liquefaction of Salix psammophila is a very complicated mixture with some highly valued chemicals. In order to separate the chemicals from bio-oil, solvent extraction using nine solvents with different polarities were investigated in detail. The bio-oil extraction yield of the nine solvents were from high to low: tetrahydrofuran > toluene > ethyl acetate > acetone > ether > methylene chloride > methanol > petroleum ether > n-hexane. Based on their extraction yield, an efficient solvent combination of n-hexane, ethyl acetate, and tetrahydrofuran was used to separate the bio-oil through multistep extraction into three parts: light oil (26.13%), mid-weight oil (54.19%), and heavy oil (19.68%). These fractions were characterized by gas chromatography-mass spectrometry, Fourier transform infrared spectroscopy, 1H nuclear magnetic resonance spectroscopy, and thermogravimetric analysis. The results showed that most of the highly valued chemicals were contained in the light oil; the mid-weight oil consisted of aromatic oligomer derived from the decomposition of lignin, which could be a promising candidate for partial substitute for petroleum-asphalt binder; the heavy oil was rich in alkanes.

Synthesis of a Novel Optically Tunable Amphiphilic Poly(p-phenylene): Influence of Hydrogen Bonding and Metal Complexation on Optical Properties1

Abstract: A series of optically tunable amphiphilic conjugated polymers, poly(2-hydroxy-5-alkoxy-p-phenylene) (1) containing long alkyl chains, were prepared by Suzuki polycondensation using 2,5-dibromo-1-benzyloxy-4-alkoxybenzene and bis(boronic ester) monomers. All polymers showed good solubility in common organic solvents such as tetrahydrofuran (THF), chloroform, toluene, and dimethylformamide (DMF). Optical properties of all polymers were investigated in THF at room temperature under neutral conditions, and emission maxima were observed in the violet region (λemi = 401−403 nm). By the addition of stoichiometric amount of a base (e.g., aqueous NaOH solution), absorption maxima shifted to the blue region (λemi = 474−468 nm). The ionochromic effect of target polymers with transition metal ions such as Fe3+, Cu2+, and Co2+ was also reported. In the presence of metal ions, the optical properties of polymers showed interesting tunability of emission maxima, Δλmax (140−26 nm). X-ray diffraction studies using powdered...

Regioselective formation of peroxyquinolatocobalt(III) complexes in the oxygenation of 2,6-di-t-butylphenols with cobalt(II) Schiff-base complexes

Abstract: The oxygenation of 2,6-di-t-butylphenols with five-co-ordinate cobalt(II) Schiff-base complexes in aprotic solvents, such as CH2Cl2, thf, and dmf (thf = tetrahydrofuran, dmf = dimethylformamide), has been found to result in regioselective formation of peroxyquinolatocobalt(III) complexes. The regioselectivity depends on the nature of the substituent at the 4-position of the phenol used: 4-alkyl-2,6-di-t-butylphenols (1) afford peroxy-p-quinolatocobalt(III) complexes, whereas peroxy-o-quinolato-complexes are formed from 4-aryl-2,6-di-t-butyl phenols (4). The initiation of the oxygenation is hydrogen abstraction by superoxocobalt(III) species from the phenols to give the corresponding phenoxy-radicals (10). Rapid reduction of (10) with cobalt(II) species follows giving rise to a phenolatocobalt(III) complex intermediate, within which dioxygen is incorporated. The regioselectivity of the oxygenation is attributable to the formation of the phenolatocobalt(III) complex intermediate. Crystals of the peroxy-p-quinolatocobalt(III) complex (2a) are orthorhombic, space group P212121, with a= 33.749(11), b= 11.844(5), c= 9.329(4)A, and Z= 4. The crystal structure has been refined from 3 018 diffractometer data to R= 0.067.