Boron Trifluoride Ethyl Ether Research Articles

Synthesis and Biological Activities of New 1,2,3,4- Tetrahydroquinoline Derivatives Using Imino Diels-Alder Reaction

This research contains the preparation of some novel derivatives of tetrahydro quinolone. First step, includeprepared new Schiff’s bases compounds (I1-I5) were prepared by the direct condensation between diaminecompounds and aromatic aldehydes substituted by different groups. Tetrahydroquinoline derivativescompounds (I6-I10) were prepared through imino Diels-Alder reaction using the derivatives of Schiff basewith cinnamic acid, and Boron tri fluoride ethyl etherate (BF3.Et2O) as a catalyst. The prepared compoundswere identified by infrared spectra, 1H-NMR, and 13C-NMR. Antibacterial activity of the prepared compoundswas measured by using three pathogenic microorganisms including Staphyloccus haemolyticus, Klebsiellapneumonia,and Candida albicans. Also, a comparative study was achieved to study the biological activityof these prepared compounds using Agar Diffusion method.

Synthesis and Optoelectronic Properties of Free-Standing Polythiophene Cross-Linking Polycarbazole Films

Cross-linking poly(9-(6-(thiophene-3-yl)hexyl)-9H-carbazole) (PTh-H-Cz) films were synthesized one-step by anodic oxidation of its monomer precursor 9-(6-(thiophene-3-yl)hexyl)-9H-carbazole (Th-H-Cz) in boron trifluoride-ethyl ether (BFEE). The electrochemistry, electronic properties, electrochromic, and thermoelectric properties of the resultant free-standing PTh-H-Cz films were minutely studied. The PTh-H-Cz film-modified electrode exhibited reversible redox activity and good stability, combining the features of polythiophene and polycarbazole. The optical band gaps (Eg) of the polymer was calculated to be 2.52 eV. The HOMO and LUMO energy levels of PTh-H-Cz film were -4.13 and -1.61 eV, respectively. During its doping/dedoping process, the polymer film displayed a reversible color change from yellow green in the neutral state to atrovirens in the oxidation state. Additionally, the electrical conductivity of free-standing PTh-H-Cz films was determined to be only 1.2×10-3 S cm−1, but the film showed a very high but unstable Seebeck coefficient in the range of 5000-10000 μV K−1 at ambient temperature.

Three novel electrochemical electrodes for the fabrication of conducting polymer/SWCNTs layered nanostructures and their thermoelectric performance

Single-walled carbon nanotubes (SWCNTs), PEDOT:PSS/SWCNTs, and SWCNTs/PEDOT:PSS nanofilms were used as working electrodes to electrodeposit polyaniline (PANI) in a mixed alcohol solution of isopropyl alcohol (IPA), boron trifluoride ethyl ether (BFEE), and polyethylene glycol (PEG). The thermoelectric (TE) performances of the resulting nanofilms were systematically investigated. SWCNTs/PEDOT:PSS/PANI nanofilms showed a relatively high electrical conductivity value of 232.0 S cm−1. The Seebeck coefficient was enhanced and exhibited the values of 33.8, 25.6, and 23.0 μV K−1 for the SWCNTs/PANI, PEDOT:PSS/SWCNTs/PANI, and SWCNTs/PEDOT:PSS/PANI films, respectively. The maximum power factor achieved was 12.3 μW m−1 K−2. This technique offers a facile and versatile approach to a class of layered nanostructures, and it may provide a general strategy for fabricating a new generation of conducting polymer/SWCNTs materials for further practical applications.

An impedance-morphology study on poly(3-methylthiophene) coated electrode obtained in boron trifluoride diethyl etherate–acetonitrile

In this study, 3-methylthiophene (3-mTh) was polymerized electrochemically in different ratios of boron trifluoride ethyletherate (BFEE) in acetonitrile (ACN) to investigate the effect of BFEE on impedance and polymer morphology. The monomer oxidation potentials were decreased by adding BFEE in ACN, from 1.25V in 0% BFEE (0.1M NaClO4–ACN) to 0.63V in 15% BFEE–ACN, due to interaction (complexation) between the 3-mTh and BFEE during electrochemical polymerization of 3-mTh. Electrochemical Impedance Spectroscopic (EIS) experiments carried out in the electrolyte/poly(3-mTh)/ITO-PET electrodes in ACN solution in the monomer-free solution, indicated that as the ratio of BFEE was decreased, the capacitive behavior of the polymer was increased. The reduction products of BFEE and BFEE interact with positively charged oligomers by facilitating the deprotonation and resulting a lower oxidation potential.

Study on Preparing Light Colored C<sub>9</sub> Petroleum Resins with High Softening Point

Polymerizable C9 fraction was cut by atmospheric distillation of raw C9 fraction from thermal cracking. The obtained fraction polymerized using boron trifluoride ethyl ether as catalyst and then the polymerized mixture was washed by warm 10%wt Na2CO3 aqueous solution and distilled water and separated by vacuum distillation for producing light colored C9 petroleum resins with high softening point. The suitable conditions for polymerization process, washing process, vacuum distillation process were investigated to improve the C9 petroleum resins production. Under these conditions, the petroleum resins product with Gardner color index of 4-5 and softening point of 102-120°C could be obtained.

A new approach to the Schiff base-substituted oligophenols: The electrochromic application of 2-[3-thienylmethylene]aminophenol based co-polythiophenes

Two new copolymers were synthesized by electrochemical polymerization of 2-[3-thienylmethylene]aminophenol (2,3-TMAP) and poly-2-[3-thienylmethylene]aminophenol (P-2,3-TMAP) with thiophene (Th) and the obtained thiophene copolymers were examined as electrochromic materials. Electro copolymerization reactions of the compounds were performed in acetonitrile (AN)/boron trifluoride ethyl etherate (BF 3EtE) solvent mixture (9:1, v/v) where LiClO 4 utilized as the supporting electrolyte. After electro copolymerization reaction, obtained electrochromic films deposited on ITO glass plates, 2,3-TMAP-co-Th and P-2,3-TMAP-co-Th, were investigated as spectroelectrochemically. The new electrochromic materials derived from Schiff base substituted-phenol/oligophenols are red colored at low potentials and blue colored at high potentials. Electro copolymerization mechanism was identified. Spectroelectrochemical monitoring showed good absorption recovery for P-2,3-TMAP-co-Th, while absorbance decrease was observed for 2,3-TMAP-co-Th during the repeated potential scans. Suitable potential range for operating the device from red to blue was found to be between 0 and +1.4 V. P-2,3-TMAP-co-Th showed 12–13% transmittance changes at applied potentials and the response times were 3.1 and 4.1 s for 476 and 800 nm, respectively. As a result P-2,3-TMAP-co-Th may be good candidate for electrochromic devices and can be thought as a feasible nominee for anodically coloring electrochromic layers in ECDs.

ChemInform Abstract: The Generation of Difluoroenolates from Trifluoroethanol and Reproducible Syntheses of α,α-Difluoro-β-hydroxy Ketones.

Metallated difluoroenol carbamate 1 reacted with aldehydes and ketones in the presence of highly oxophilic Lewis acid boron trifluoride–ethyl ether; the Lewis acid attenuated the transacylation reaction to the corresponding enolates so that allylic alcohols could be isolated. Treatment of the allylic alcohols with strong base afforded difluoroenolates which could be trapped cleanly in aldol reactions.

Redox thermodynamics, conductivity and Raman spectroscopy of electropolymerized furan–thiophene copolymers

Electrochemical copolymerization of furan and thiophene was performed at constant electrode potential in a binary solvent system consisting of boron trifluoride-ethyl ether and an additional amount of ethyl ether (mole ratio 1:2). The homopolymers and copolymers obtained were studied with in situ resonance Raman spectroscopy and in situ conductivity measurements. In situ resonance Raman spectroscopy of the copolymers shows spectroscopic properties intermediate between polyfuran and polythiophene. The conductivity of homo- and copolymer films is almost restored when the potential shift direction is reversed. The redox thermodynamics of homo- and copolymer films were also determined using the Nernst plots constructed from absorbance measurements performed in situ at various doping levels.

In situ UV–vis- and FT-IR-spectroscopy of electrochemically synthesized furan–thiophene copolymers

Electrochemical copolymerization of furan and thiophene was performed at constant electrode potential in a binary solvent system consisting of boron trifluoride-ethyl ether and an additional amount of ethyl ether (mole ratio 1:2). The homopolymers and copolymers obtained were studied with in situ UV–vis- and FT-IR-spectroscopy. An electrochemical degradation mechanism for furan–thiophene copolymers in acetonitrile and in aqueous solution is proposed based on FT-IR spectroscopy data.

Synthesis and metal-ion binding properties of new N2S4- and N2S5-donor macrocycles

Synthetic procedures for new N2S4- and N2S5-donor macrocycles (2 and 4) were given. The ligands were prepared by the reaction of NaBH4 with the appropriate macrocyclic diamide in the presence of boron trifluoride ethyl etherate in dry tetrahydrofuran (THF). Solvent extraction method was used to evaluate metal-ion binding properties of the new ligands. The solvent extraction experiments suggested that the reduced macrocycles have Ag+ and Hg2+ selectivities compared to Pb2+, Co2+, Zn2+, Ni2+, Cu2+, Mn2+ and Cd2+ ions. The extraction constants (log K ex) and complex compositions were determined for Ag+ and Hg2+ complex of compound (4).

Electrosynthesis of polyfuran in acetonitrile–boron trifluoride–ethyl ether mixture and its device application

AbstractElectrochemical polymerization of furan was achieved in acetonitrile/boron trifluoride/ethyl ether (CH3CN/BF3/EE) mixture in the presence of tetrabutylammonium tetrafluoroborate via constant potential electrolysis at 1.4 V versus Ag/AgCl. Electrochemical behavior of furan was investigated in the same solvent mixture of varying ratios, utilizing cyclic voltammetry. Free‐standing polyfuran (PFu) films were obtained in CH3CN/BF3/EE mixture (2/4/4; v/v/v) and characterized using FTIR spectroscopic technique. Spectroelectrochemical behavior of the PFu film was investigated by recording the electronic absorption spectra, in situ, in monomer‐free solution. It is observed that PFu film can be reversibly cycled between –0.1 V (gray) and + 0.6 V versus Ag‐wire (gray color); however, this behavior diminishes in the presence of water. Electrochromic device application of PFu film with poly(ethylene dioxythiophene) was also studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 871–876, 2007

One-step axial acetoxylation at C-23. A new method for the functionalization of the side chain of steroid sapogenins

Treatment of steroid sapogenins with diacetoxyiodobenzene (DIB) and boron trifluoride ethyl etherate in acetic acid led to the introduction of an axial acetoxyl group at position C-23 of the side chain.

Electrochemical copolymerization of furan and 3-methyl thiophene

Electrochemical copolymerization of furan and 3-methyl thiophene was performed potentiostatically in a binary solvent system consisting of boron trifluoride-ethyl ether and additional ethyl ether (mole ratio 2:1). The product obtained was characterized by cyclic voltammetry and infrared spectroscopy. The influence of polymerization potential on the synthesis of the copolymer was investigated. The lower potential favored the incorporation of furan units into the copolymer. The conductivities of synthesized homopolymers and copolymers were determined by the four-probe technique. Thermogravimetric analysis (TGA) was also carried out to investigate the properties of the copolymer.

High‐Quality Electrochromic Polythiophenes via BF3·Et2O Electropolymerization

AbstractElectrochemical polymerization in the strong Lewis acid, boron trifluoride ethylether (BFEE), has been used to prepare electrochromic polythiophene (PTh) and its derivatives: poly(3‐methylthiophene) (PMeTh), poly(3‐bromothiophene) (PBrTh), and poly(3,4‐dibromothiophene) (PDBrTh). The polymerization processes and properties of the resultant films are compared, where possible, to those carried out in traditional organic electrochemical solvents. The polymerization of these high oxidation potential thiophene monomers in BFEE yielded good‐quality, homogenous, and smooth electroactive and electrochromic films that could be repeatedly switched in common electrochemical solvents up to 240, 1380, 560, and 420 cycles for PTh, PMeTh, PBrTh, and PDBrTh, respectively, for 50 % retention of electroactivity. A colorimetric study of these films showed distinctive color changes between red and blue as they were switched between reduced and oxidized states. These findings allow the use of commercially available high oxidation potential thiophene monomers to provide electrochromic polymers, avoiding the use of other custom‐synthesized monomers.

Electropolymerization of thiophene in acetonitrile with boron trifluoride-ethyl ether as supporting electrolyte

Polythiophene (PTh) was prepared by electrochemical polymerization of thiophene in acetonitrile solution with boron trifluoride-diethyl ether (BFEE) as supporting electrolyte. The electropolymerization processes were investigated by cyclic voltammetry. The free-standing PTh film was characterized by FT-IR, XPS spectroscopy and SEM respectively. The effects of BFEE concentration on the polymerization processes of thiophene and on the properties of the as-prepared PTh films were discussed.

Low Potential Electrochemical Synthesis of Polyfuran and Characterization of the Obtained Free-Standing Film

A free-standing polyfuran (PFu) film has been successfully synthesized by electrochemical polymerization of furan at low potential (1.2 V vs Ag/AgCl) in a binary solvent system consisting of boron trifluoride−ethyl ether (BFEE) and additional ethyl ether (EE). The obtained polymer contains much less ring-opened component and shows higher conductivity than that prepared by chemical method or by electropolymerization in other solvent systems. Its electric conductivity is as high as 10-2 S cm-1 both in its electrochemically doped state and chemically doped state with I2. Moreover, the obtained free-standing film shows good mechanical properties, which makes itself a powerful competitor to other conducting polymers. The orientation of PFu deposited on Au and stainless steel electrode was investigated by surface enhanced Raman spectra (SERS) and reflection−absorption infrared spectra (RA-IR) techniques. The furan ring in the polymer chain is inclined to be arranged parallel to the metal surface at the early stage of deposition.

The electrochemical copolymerization of pyrrole and furan in a novel binary solvent system

Electrochemical copolymerization of furan and pyrrole was performed potentiostatically in a binary solvent system consisting of boron trifluoride ethyl ether and additional ethyl ether. The influence of applied polymerization potential and the monomer feed ratio of furan and pyrrole on the synthesis of copolymer was investigated. The higher potential favored the incorporation of furan units into the copolymer, while the amount of pyrrole units incorporated into the film increased with the increasing concentration of pyrrole in the solution. The film obtained was characterized by cyclic voltammetry, infrared and Raman spectroscopies.

Synthesis of high-quality polypyrrole in a binary solvent system consisting of boron trifluoride-ethyl ether and additional ethyl ether

Polypyrrole (PPy) was electrochemically synthesized in boron trifluoride ethyl ether (BTEE) whose acidity was adjusted with additional ethyl ether (EE). A high quality PPy film can be synthesized in a wide mole ratio range of BTEE/EE and under mild conditions. The obtained film showed the highest tensile strength (90MPa) we had ever seen and good anisotropy in electrical conductivity. The structure was investigated using surface enhanced Raman scattering (SERS).

The generation of difluoroenolates from trifluoroethanol and reproducible syntheses of α,α-difluoro-β-hydroxy ketones

Metallated difluoroenol carbamate 1 reacted with aldehydes and ketones in the presence of highly oxophilic Lewis acid boron trifluoride–ethyl ether; the Lewis acid attenuated the transacylation reaction to the corresponding enolates so that allylic alcohols could be isolated. Treatment of the allylic alcohols with strong base afforded difluoroenolates which could be trapped cleanly in aldol reactions.

Synthesis of 4-cyanophenyl 4-azido-4-deoxy-1,5-dithio-β- d-xylopyranoside

l-Arabinose diethyl dithioacetal was converted, via its 4- azido-5-S- benzoyl-4-deoxy-2,3-O- isopropylidene-5-thio- d- xylose diethyl dithioacetal, into 4-azido-4-deoxy-5-thio-α- d-xylopyranose triacetate 29. Glycosidation of 29 with 4-cyanothiophenol in the presence of trimethylsilyl triflate gave the 4-cyanophenyl 2,3-di- O-acetyl-4-azido-4-deoxy-1,2-dithio-α- and -β- d-xylopyranosides 31 and 33 as well as 3-O- acetyl-2,5-anhydro-4-azido-4-deoxy-5-thio- d-lyxose bis(4-cyanophenyl ) dithioacetal 34 in a 8:2:1 respective ratio. Treatment of 29 with hydrogen bromide in acetic acid yielded a 1:4 mixture of 2,3- di-O- acetyl-4-azido-4-deoxy-5-thio- d- xylopyranosyl bromide 38 and 2,3- di-O- acetyl-5-bromo-5-deoxy-4-thio- l- arabinofuranosyl bromide 40. Reaction of the mixture of bromides 38 and 40 with 4-cyanothiophenol in the presence of potassium carbonate afforded the expected 31 and 33 only in traces, while 2-(1 R,2 S,-1,2-di- O-acetyl-1,2-dihydroxy-but-3-en-1-yl)-5-cyano-1,3-benzodithiole and 4-cyanophenyl 2,3- di-O- acetyl-5-S-(4- cyanophenyl)-1,4,5- trithio-α- l- arabinofuranoside ( 42) were isolated in 18% and 20% yield, respectively. The formation of these two derivatives is tentatively explained by involvement of a radical reaction mechanism. When O-(2,3- di-O- acetyl-4-azido-4-deoxy-5-thio-α- d- xylopyranosyl) trichloroacetimidate was used as donor and boron trifluoride ethyl etherate as promoter, 31 and 33 were formed in excellent yield (96%) in a 2:1 ratio. The glycosides, obtained on deacetylation of 33, 34, and 42 showed a significant antithrombotic activity on rats.