Diethyl Ether Solution Research Articles

Raman spectroscopic studies on the structural changes of electrosynthesized polythiophene films during the heating and cooling processes

Polythiophene (PT), poly (3-chlorothiophene) and poly (3-methylthiophene) have been electrochemically synthesized by direct oxidative polymerization of corresponding monomers at stainless steel electrode and in boron trifluoride diethyl etherate solution. The as-grown PT films have been peeled off from the electrode surfaces and characterized by resonance Raman spectroscopy in the temperature scale of 78–573 K. During the heating process, the Raman bands related to the oxidized species decreased gradually, mainly due to the effects of oxygen and moisture in air. Finally, the polymers changed into the neutral states and then decomposed. During the cooling process, the polymer chain segments of the neutral species changed from a disordered (coil-like) to an ordered (rod-like) structure and caused the elongation of conjugated chain length. This led to the dramatic decrease of the Raman intensities of the bands related to the neutral species. On the other hand, the Raman intensities of the bands associated with the oxidized species are nearly independent of temperature. This is mainly because the oxidized species have quinoidic structures and their conformation does not change during the cooling process.

Two polymorphs, with Z' = 1 and 2, of 2-amino-4-chloro-6-morpholinopyrimidine in P21/c, and 2-amino-4-chloro-6-piperidinopyrimidine, which is isomorphous and almost isostructural with the Z' = 2 polymorph.

Crystallization of 2-amino-4-chloro-6-morpholinopyrimidine, C(8)H(11)ClN(4)O, (I), yields two polymorphs, both with space group P2(1)/c, having Z' = 1 (from diethyl ether solution) and Z' = 2 (from dichloromethane solution), denoted (Ia) and (Ib), respectively. In polymorph (Ia), the molecules are linked by an N-H...O and an N-H...N hydrogen bond into sheets built from alternating R(2)(2)(8) and R(6)(6)(40) rings. In polymorph (Ib), one molecule acts as a triple acceptor of hydrogen bonds and the other acts as a single acceptor; one N-H...O and three N-H...N hydrogen bonds link the molecules in a complex chain containing two types of R(2)(2)(8) and one type of R(4)(4)(18) ring. 2-Amino-4-chloro-6-piperidinopyrimidine, C(9)H(13)ClN(4), (II), which is isomorphous with polymorph (Ib), also has Z' = 2 in P2(1)/c, and the molecules are linked by three N-H...N hydrogen bonds into a centrosymmetric four-molecule aggregate containing three R(2)(2)(8) rings.

Photoinduced electron transfer of chlorophyll in lipid bilayer system

Photoinduced electron transfer from chlorophyll-a throughtheinterface of dipalmitoylphosphatidylcholine (DPPC) headgroup of the lipid bilayers was studied with electron magnetic resonance (EMR). The photoproduced radicals were identified with electron spin resonance (ESR) and radical yields of chlorophyll-a were determined by double integration ESR spectra. The formation of vesicles was identified by changes in measured λmax values from diethyl ether solutions to vesicles solutions indirectly, and observed directly with SEM and TEM images. The efficiency of photosynthesis in model system was determined by measuring the amount of chlorophyll-a radical yields which were obtained from integration of ESRspectra.

Poly(3-chlorothiophene) films prepared by the direct electrochemical oxidation of 3-chlorothiophene in mixed electrolytes of boron trifluoride diethyl etherate and sulfuric acid

3-Chlorothiophene (CT) was electrochemically polymerized in mixed electrolytes of a boron trifluoride diethyl etherate solution containing 0–20% (by volume) sulfuric acid. The oxidation potentials of the monomer in these media were measured to be only 1.06–1.31 V (vs Ag/AgCl). These values were much lower than that of CT in acetonitrile and 0.1 mol/L (Bu)4NBF4 (1.92 V vs Ag/AgCl). Poly(3-chlorothiophene) (PCT) films with conductivities of 0.1–2 S cm−1 were obtained. The structure, morphology, and electrochemical behavior of the PCT films also were investigated. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 502–509, 2003

A new protocol for the one-pot preparation of highly diastereomerically enriched secondary amines and β-amino esters mediated by lithium perchlorate solution in diethyl ether

A highly diastereoselective one-pot, three-component method for the preparation of several secondary amines and amino esters is reported. Treatment of aldehydes (aliphatic or aromatic) with chiral amines and functionalized organozinc reagents (e.g. BrZnCH 2COOR, allylzinc bromide) in the presence of trimethylsilylchloride with 5 M lithium perchlorate in diethyl ether produces N-alkylamino esters or N, N-dialkylamines in good yields and high diastereoselectivities. The diastereomeric ratios of the secondary amines prepared by this method were lower in comparison to those of the N-alkylamino esters formed in the same way.

Electrochemical fabrication of aligned microtubular heterojunctions of poly(p-phenylene) and polythiophene

Aligned microtubular heterojunctions of poly(p-phenylene) (PPP) and polythiophene (PTh) were fabricated by successive electrochemical oxidations of benzene and thiophene in freshly distilled boron trifluoride–diethyl ether (BFEE) solution and using a microporous alumina membrane with pores of 200 nm diameter as the template. The morphology and chain structure of the microtubular heterojunctions were studied by scanning and transmission electron microscopies and Raman spectroscopy. The current (I)–voltage (V) curves revealed that the aligned microtubular heterojunctions had a better rectification effect than that of the normal PPP/PTh bilayer heterojunction.

Determination of the Solution Acidity of Tris(trimethylsilyl)silane

The acidity of (Me3Si)3SiH was determined in diethyl ether solution by reactions of (Me3Si)3SiLi·3THF with a series of C−H acids. (Me3Si)3SiH and 9-phenylxanthyllithium (pK = 28.7) form in diethyl ether solution an equilibrium mixture in which the [silane]/[silyl anion] ratio is 12:7, corresponding to a pK value for (Me3Si)3SiH of 29.4.

Solvent-dependent mixed complex formation-NMR studies and asymmetric addition reactions of lithioacetonitrile to benzaldehyde mediated by chiral lithium amides.

Lithioacetonitrile and a chiral lithium amide with an internally coordinating methoxy group form mixed dimers in diethyl ether (DEE) and in tetrahydrofuran (THF) according to NMR studies. Based on the observed (6)Li,(1)H heteronuclear Overhauser effects, in THF lithioacetonitrile is present in a mixed complex with the chiral lithium amide, and this complex has a central N-Li-N-Li core. In DEE, on the other hand, the acetonitrile anion bridges two lithiums of the dimer to form a central six-membered Li-N-C-C-Li-N ring. Gauge individual atomic orbital DFT calculations of the (13)C NMR chemical shifts of the DEE- and THF-solvated mixed dimers show good agreement with those obtained experimentally. Lithioacetonitrile complexed to the chiral lithium amide has been employed in asymmetric addition to benzaldehyde in both DEE and THF. In THF the product, (S)-3-phenyl-3-hydroxy propionitrile, is formed in 55 % ee and in DEE the R enantiomer is formed in 45 % ee. This change in stereoselectivity between solutions in DEE and THF was found to be general among a number of different chiral lithium amides, all with an internal chelating methoxy group.

Chiral sulfur diphosphazanes derived from S-(Ph 2P) 2N(CHMePh) and its rhodium(I), (III) and iridium(III) complexes. Crystal structures of Ph 2P(S)N(CHMePh)PPh 2, {Ph 2P(S)} 2N(CHMePh) and [(Cp*)MCl{η 2-P,S-Ph 2PNHP(S)Ph 2}]BF 4, Cp*=η 5-C 5Me 5; M=Rh, Ir

The reaction of S-(Ph 2P) 2N(CHMePh) with sulfur (1:1 molar ratio) in diethyl ether solution leads to S-Ph 2P(S)N(CHMePh)PPh 2 ( 1). The disulphide S-{Ph 2P(S)} 2N(CHMePh) ( 2), was obtained when the reaction was carried out in tetrahydrofuran with an excess of sulfur (1:5 molar ratio). 1 reacts with the solvated rhodium (I) complex [Rh(cod)S x]BF 4 to afford the cationic complex [Rh(cod){η 2-S,P-Ph 2P(S)N(CHMePh)PPh 2}]BF 4 ( 3). However, when the above reaction was carried out with 2, cleavage of the CN bond of the ligand occurred, to yield the complex [Rh(cod)(η 2-S,S-{Ph 2P(S)} 2NH)]BF 4 ( 4). Reactions of 1 with the fragments of Rh (III) and Ir (III) [Cp*MClS x ]BF 4 lead to cleavage of the CN bond of the ligand yielding cationic complexes, [(Cp*)MCl{η 2-P,S-Ph 2PNHP(S)Ph 2}]BF 4 (M=Rh, 5; Ir, 6]. Crystal structures of 1, 2, 5 and 6 have been determined by X-ray diffraction methods. Compounds 1 and 2 crystallize in the same space group P2(1)2(1)2(1). The molecular structure of 1 shows a nearly trigonal planar nitrogen atom bound to two different phosphorus atoms and to the chiral carbon atom. Compound 2 acquires a twisted conformation with the two sulfur atoms adopting mutually trans positions with respect to the PNP backbone.

The preparation and structure of novel sulfimide systems; X-ray crystal structures of 1,4-(PhS{NH})2C6H4 (and dihydrate), 1,2-(PhS{NH})(PhS)C6H4·H2O and of [Ph2SNH] and its hydrate

Treatment of 1,4-(PhS)2C6H4 and 1,2-(PhS)2C6H4 with the appropriate amount of O-mesitylsulfonylhydroxylamine (MSH) yields the corresponding protonated sulfimides, both of which may be deprotonated with DBU to give the hydrated free sulfimides 1,4-(PhS{NH})2C6H4·2H2O 1a and 1-(PhS{NH})-2-(PhS)C6H4·H2O 2a. The X-ray crystal structures of both 1a and 2a, together with that of the well-known sulfimide Ph2SNH·H2O 3a, all reveal extended hydrogen-bonded arrays involving the N–H units and the waters of crystallisation. Crystals of 1b, the dehydrated form of 1a, also readily form, while removal of the water from 3ain vacuo followed by slow evaporation of a solution in diethyl ether under anaerobic conditions leads to crystals of Ph2SNH 3b; the X-ray crystal structures of both 1b and 3b also reveal extended arrays formed from N–H⋯N interactions. In contrast, dehydration of 2a breaks down the extended structure resulting in the formation of an oil.

Synthesis and characterization of high surface area aluminium and alumina microtubes from carbonaceous materials

An original synthesis route to obtain high surface area metallic aluminium and alumina microtubes was developed. Samples were prepared by adsorption of an aluminium hydride solution in diethyl ether on fibrous carbonaceous substrates, followed by calcination at temperatures ranging from 250 °C to 1600 °C. The surface area (BET) of samples obtained after substrate elimination is about 45 m2 g−1. The crystallinity of samples was determined by X-ray diffraction and their morphology was observed by scanning electron microscopy.

Detection Method of Irradiated Chicken by GC Analysis of 2-Alkylcyclobutanones and Hydrocarbons Using Soxhlet Extraction and Florisil Chromatography.

A procedure was established for the detection of irradiated chicken by GC/FID analysis of2- alkylcyclobutanones (RCBs) and hydrocarbons (HCs) using cleanup by Soxhlet extraction and Florisil chromatography.Fat extract was obtained from irradiated chickens by a Soxhlet apparatus. A concentrated fat extract containing200 mg of fat with 2 μg of n-eicosane as internal standard (IS) was applied to Florisil columns, which were deactivated by adding 17parts of water to 100 parts of adsorbent. The HCs were eluted in 60 ml of n-hexane. This eluate was concentrated and analyzed by GC/FID. After 150ml of n-hexane was eluted from the same column, RCBs were eluted with 120ml of 1% diethyl ether solution in n-hexane. This eluate was concentrated to 0.2ml and 0.1μg of 2-cyclohexylcyclohexanone (IS) was added to the mixture, which was analyzed by GC/FID. This process rendered it possible to detect HCs and RCBs efficiently and simultaneously.HCs and RCBs were detected in chicken meat irradiated at 0.5 kGy by GC/FID.

Raman Spectroscopic and Electrochemical Studies on the Doping Level Changes of Polythiophene Films during Their Electrochemical Growth Processes

Polythiophene (PT), poly(3-chlorothiophene) (PCT), and poly(3-methylthiophene) (PMeT) have been electrochemically deposited on mirrorlike stainless steel (SS) electrode surfaces by direct oxidative polymerization of corresponding monomers in boron trifluoride diethyl etherate (BFEE) solution. The doping levels of as-grown thin films have been determined electrochemically. The results demonstrated that PTs were formed nearly in neutral state initially and their doping levels increased during electrochemical growth processes. Monomer structure and electrolyte have strong effects on the doping levels of PTs with a given thickness. Raman spectroscopic studies also confirmed these findings. Furthermore, it is found that the oxidized species of polythiophene and poly(3-chlorothiophene) are mainly presented in radical cations, while dications are favored to be formed in poly(3-methylthiophene) with a doping level higher than ca. 5%.

Raman investigations of indium iodide complexes: the species present in aqueous and diethyl ether solutions

AbstractRaman spectra of aqueous indium (III) iodide solutions, with and without added HI, reveal an equilibrium between two species: the complex anion InI4− (ν1 = 139 cm−1) and the solvated molecule InI3(H2O)x (νsym = 158 cm−1). The complex acid HInI4 is transferred from the aqueous acidic solution by solvent extraction; spectra of this species and the ether adduct InI3·Et2O (νsym = 151 cm−1) are reported. Copyright © 2001 John Wiley & Sons, Ltd.

Rate acceleration and subsequent retardation of Diels-Alder reactions in LiClO4-diethyl ether: an experimental investigation.

The experimental kinetic data for several Diels-Alder reactions show why a 5 M LiClO(4)-diethyl ether (LPDE) solution offers maximum enhancement of reaction rates, endo/exo ratios, and yields. These reactions, if carried out in LPDE solutions of concentrations higher than 5 M, show a substantial decrease in these kinetic parameters. This decrease is attributed to the very high viscosity of LPDE solutions near saturation, though this interpretation is not consistent when considered in terms of sizes of the diene and dienophile. The monoetherates, dietherates, and higher other clusters in LPDE solutions and their relationship with the Lewis acid catalysis by Li+ offer a more plausible explanation of both the enhancement and the decrease of the rate of Diels-Alder reactions in this medium.

One-pot synthesis of trans-β-alkylstyrenes

One-pot synthesis of ( E)-alkenes 5 from the reactions of aldehyde 1 and nitromethane 2 in the acetic acid solution and then with triethylborane 4 in the biphase of diethyl ether and aqueous solution in the presence of oxygen in air was reported. Various ( E)-alkenes 7 could also be prepared when different kinds of secondary or tertiary alkyl iodides 6 were used under similar conditions.

Electrochemical polymerization of thianaphthene

Thianaphthene has been electrochemically polymerized in pure boron trifluoride diethyl etherate (BFEE) solution or in a mixed electrolyte of BFEE and concentrated sulfuric acid (SA). The addition of a certain amount of sulfuric acid into BFEE accelerated the polymerization and also increased the current efficiency of the electrosynthesis. Poly(thianaphthene) (PTN) in the dedoped state is soluble in usual strong polar organic solvents such as dimethyl sulfoxide (DMSO), N, N-dimethylformamide (DMF) and N-methyl pyrrolidinone (NMP). Its structure has been examined by infrared, H 1-NMR and UV spectra. Fluorescent spectral studies indicate that the polymer is a strong blue light emitter.

Novel synthesis of alkenes via triethylaluminum-induced free radical reactions of alkyl iodides and β-nitrostyrenes

Reactions of (E)-β-nitrostyrenes 1 with triethylaluminum (Et3Al) 2 and alkyl iodide (RI) 3, 4, or 5 in the presence of benzoyl peroxide in diethyl ether solution at room temperature to give 60–100% of the different (E)-alkenes 6, 7, or 8. Under similar conditions, 95% of 1-adamantyl-2-(4-methoxyphenyl)ethene 10 or 80% of 1-(4-oxoadamantyl)-2-(4-methoxyphenyl)ethene 12 also can be easily prepared by using 1-iodoadamantane 9 or 5-iodo-2-adamantanone 11 and 2.

Linear and Hyperbranched Poly(silyl ester)s: Synthesis via Cross-Dehydrocoupling-Based Polymerization, Hydrolytic Degradation Properties, and Morphological Analysis by Atomic Force Microscopy

Poly(silyl ester)s with differing compositions and architectures were synthesized via cross-dehydrocoupling polymerizations of AB and AB2 monomers. Three poly(silyl ester)slinear poly(dimethylsilyl benzoate), linear poly(diisopropylsilyl benzoate), and hyperbranched poly(dimethylsilyl benzoate)were synthesized through the dehydrocoupling polymerization of 4-(dimethylsilyl)benzoic acid, 4-(diisopropylsilyl)benzoic acid, and 3,5-bis(dimethylsilyl)benzoic acid, respectively, as 10 M solutions in ethylene glycol diethyl ether in the presence of 0.25 mol % of 10 wt % palladium on activated carbon at 100 °C under argon for 1−3 days. The characterization of each polymer included infrared (IR), 1H NMR, 13C NMR, and 29Si NMR INEPT spectroscopies, size exclusion chromatography (SEC), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The degree of branching of hyperbranched poly(dimethylsilyl benzoate) was 51%, as determined by 1H NMR spectroscopy, with spectral analysis confirmed throug...

Stabilized Terphenyl-Substituted Digermene Derivatives of Simple Organic Groups and Their Halide Precursors: Preference for Symmetrically Bonded Structures

The reaction of 1 equiv of MeMgBr, EtMgBr, or LiPh with Ge(Cl)C6H3-2,6-Trip2 (1; Trip = C6H2-2,4,6-i-Pr3) in diethyl ether solution afforded the dimers {Ge(R)C6H3-2,6-Trip2}2 (R = Me (2), Et (3), Ph (4)), which have trans-bent Ge−Ge-bonded structures that are maintained in solution. The compounds 2 and 3 are rare examples of “digermene” species having alkyl substituents. The previously described halide precursor 1 was found to crystallize simultaneously as both a V-shaped monomer and weakly Ge−Ge-bonded dimer {Ge(Cl)C6H3-2,6-Trip2}2 (5), which dissociated readily to monomers in hydrocarbon solution. This species reacted readily with pyridine (py) to form the monomeric 1:1 adduct py·Ge(Cl)C6H3-2,6-Trip2 (7), which has pyramidal coordination at germanium. The dimeric structures found for 2−4 were in sharp contrast with recently published results for their tin and lead analogues, which displayed either unsymmetric dimeric structures as in 2,6-Trip2H3C6(Me)2SnS̈nC6H3-2,6-Trip2 or monomeric structures as in Pb(Me)C6H3-2,6-Trip2. The chloro derivatives {Ge(Cl)C6H3-2,6-Trip2}n (n = 1, 2; i.e. 1 and 5) also differed from their tin congeners in that the corresponding tin dimer is associated through chloride bridging, whereas 5, and the related dimer {Ge(Cl)C6H3-2,6-Mes2}2 (6), are associated through weak element−element bonding. The experimental results are in general agreement with earlier theoretical data on the hypothetical M2H4 (M = Ge, Sn, Pb) model compounds which predicted a stable, symmetric, dimeric, Ge−Ge-bonded structure for germanium but an unsymmetric methylmethylene analogue structure for tin.