Boron Trifluoride Complexes Research Articles

Thermal stability of epoxy compounds cured with boron trifluoride complexes

The thermal resistances of epoxy resins cured with complexes of boron trifluoride with benzylamine, 2-benzylaminoethanol and 2-anilinoethanol were examined. Thermal analysis data were used to compare the thermal resistances of epoxy compusitions cured with polyamines (aliphatic and aromatic), acid anhydrides and complexes of boron trifluoride with the above amines.

Addition of boron trifluoride complexes of organocopper reagentsto aldimines containing α-hydrogens

RCu · BF 3, generated in situ from Grignard reagents, CuI, and BF 3 · OEt 2, added to aldimines containing α-hydrogens to afford secondary amines in good yields. Boron trifluoride complex of dialkylcuprate gave essentially the same result with wider application.

Identification of some boron‐based curing agents in cured epoxy systems by computer‐assisted infrared spectroscopy

AbstractThe use of computer‐assisted infrared spectroscopy has allowed identification of three different boroxines and a boron trifluoride complex used as curing agents in cured epoxy resins. Boroxines were distinguished from a boron trifluoride complex by the BO stretch absorption near 1400 cm−1 in the solid state. Detection of this absorption was enhanced by spectral subtraction methods in which the reference spectrum was that of the parent resin, or a suitably cured system of similar structure. Distinction between different boroxines was achieved by analysis of the gases evolved from samples heated at 300°C in nitrogen. Identification of the alcohol fraction of the original boroxine was improved by subtraction of the spectrum of water vapor. Boron trifluoride was detected in the gases evolved at 450–500°C from BF3‐cured systems, and also in the liquid pyrolyzates. Further simplification of the 300°C gas spectra by subtraction of alcohol and carbon dioxide revealed the presence of acrolein in the gases from boroxine‐cured systems while BF3‐cured systems yielded acetaldehyde. These differences may be associated with different end groups in the cured resins.

A direct low-temperature carbon-13 and fluorine-19 nuclear magnetic resonance study of boron trifluoride complexes with pyridines

Complexes of boron trifluoride with a series of substituted pyridines have been studied using a direct, low-temperature 13C and 19F n.m.r. technique. At temperatures from 0 to –40 °C, ligand exchange is slow enough to permit the observation of separate 13C n.m.r. signals for bulk and co-ordinated pyridine molecules. The co-ordinated pyridine shift displacements are interpreted in terms of ligand polarization and a paramagnetic effect at the nitrogen atom. The BF319F n.m.r. chemical shifts were correlated with calorimetric data in several cases, and in general provide a measure of the strength of the interaction but not of ligand basicity. Comparative complexing abilities were evaluated by studying several pyridine mixtures.

ChemInform Abstract: MAGNETIC RELAXATION STUDY OF SOLID AMMONIA‐BORON TRIFLUORIDE COMPLEX

AbstractDie Bewegungen der NH3‐ und BF3‐Gruppen im kristallinen NH3 ‐ BF3 ‐Komplex werden durch 1H‐ und 19F‐NMR‐Absorptions‐ und Spin‐Gitter‐Relaxationsmessungen in den Temp.‐Bereichen 4.2‐300 Kmit Hilfe der kontinuierlichen Methode und 89‐373 Kmit Hilfe der Impulsmethode untersucht.

CATIONIC CYCLIZATION OF GERANONITRILE AND RELATED COMPOUNDS VIA THEIR BROMOHYDRINS: APPLICATION TO THE SYNTHESIS OF (±)-SNYDEROLS

Abstract Cationic cyclization of bromohydrins of geranonitrile and homogeranonitrile in the presence of boron trifluoride complexes proceeded smoothly, giving mixtures of bromo cyclic olefins in satisfactory yields. This cyclization method was applied to the synthesis of (±)-snyderols.

Magnetic relaxation study of solid ammonia–boron trifluoride complex

Proton and fluorine magnetic resonance absorption, and spin–lattice relaxation time measurements, have been carried out on crystalline ammonia–boron trifluoride complex in the temperature ranges from 4.2 to 300 K in the continuous wave method, and from 89 to 373 K using the pulse technique. The second moment results indicated that the BF3 motion is hindered at ∼200 K, as previously reported, while the NH3 group is considerably mobile at 77 K but an additional motion occurs at 4.2 K. The magnetization decay of 1H and 19F after a 180 ° pulse showed intrinsically nonexponential behavior. The T1 data, taken as the initial decay time constant, are compared with approximate theoretical estimates including three dissimilar spins. For the 19F relaxation at high temperature, a set of three differential rate equations was reduced to a pair of two differential equations in which the effect of the third atom is taken into account in the diagonal coefficients. The temperature dependence was almost completely predicted by this treatment. Three dipolar contributions 19F–19F, 19F–11B, and 19F–1H were found to be 1.244, 2.420, and 0.222×109 s−2 for the relaxation constants, respectively. A discrepancy between theory and experiment was observed in the 1H relaxation data at high temperature and for 19F at low temperature, both of which can not be explained by assuming a two-dissimilar-spins system and require the consideration of magnetic polarization in the third atom.

Reactions of pyrazolo(1,5-a)pyrimidine derivatives with nucleophiles. I. Nucleophilic addition to 6,7-dicarbethoxypyrazolo(1,5-a)-pyrimidine-3-carbonitrile in the presence of boron trifluoride etherate.

Nucleophilic additions of phenol analogs, indoles, and enamines of cyclohexanone to 6, 7-dicarbethoxypyrazolo [1, 5-α] pyrimidine-3-carbonitrile (1) in the presence of boron trifluoride etherate are described. For example, though phenol or o-cresol (having no substituent at the para-position) reacted with 1 to give cyclohexadienylidene derivatives (3, 4), p-cresol or p-methoxyphenol gave the spiro {benzofuran-3 (2H), 7'(4'H)-pyrazolo-[1, 5-α] pyrimidine} compounds (6, 7) upon reaction with 1. Indoles reacted with 1 to give the 7-indolyl derivatives (11, 12). When 1 was treated with enamines of cyclohexanone in the presence of a slight excess of boron trifluoride etherate, 7-(2-amino-1-cyclohexenyl) pyrazolo [1, 5-α] pyrimidines (13, 14) were obtained as their boron trifluoride complexes in good yields.

スルホン化泥炭フミン酸による塩化水銀（ＩＩ）の吸着

Sulfonated peat humic acid prepared on the reaction of peat humic acid with sulfuric acid boron trifluoride complex at 100°C for 90 min was used as adsorbent for mercury (II). After shaking 100 ml of 1 ppm mercury (II) chloride aqueous solution with 5100 mg of adsorbent for 24 hr at 23°C, the residual concentration of mercury (II) in the supernatant solution was determined. It was found that the sulfonated peat humic acid selectively adsorbed mercury (II) from aqueous solution over a wide range of pH with high efficiency. The adsorption behaviour of sulfonated peat humic acid was found to be the Langmuir's isotherm. The presence of foreign metals such as sodium, calcium, cadmium (II), copper (II), lead (II), manganese (II) and iron (III) did not interfere with the adsorption of mercury (II) from aqueous solution containing 1000 times as much foreign ions as mercury (II). But presence of chloride reduced the adsorption when the concentration of chloride ion is more than 1000 ppm. Sulfonated peat humic acid which adsorbs mercury (II) can be easily regenerated by the treatment with 4 N hydrochloric acid.

The electronic structures of some van der Waals complexes of boron trifluoride

The electronic structures and energies of three van der Waals complexes of boron trifluoride namely N 2·BF 3, OC·BF 3 and Ar·BF 3 are reported. The calculated energies of complexing of these molecules are small: 4.07, 4.34 and 0.01 kcal mol −1 for N 2·BF 3, OC·BF 3 and Ar·BF 3 respectively. In the formation of these complexes a small amount of electrons (0.03) is transferred to the BF 3 species and the resulting coordination bond population (0.06) is weak. Dipole moment calculations indicate that in OC·BF 3 the BF 3 moiety is distorted out of the plane by 4° while Ar·BF 3 and N 2·BF 3 a planar configuration of BF 3 is present.

On the barrier to internal rotation in the trimethylamine complexes of boron trifluoride and borontrichloride

On the barrier to internal rotation in the trimethylamine complexes of boron trifluoride and borontrichloride

Direct carbon-13 nuclear magnetic resonance study of boron trifluoride complexes with alkyl and cyclic ketones

A study of the born trifluoride complexes of the C4–C10 cycloalkanones and nine alkyl ketones has been completed using a direct, low-temperature carbon-13 n.m.r. technique. At temperatures in the rang –85 to –125 °C, exchange is slow enough on the n.m.r. time scale to permit the observation of separate 13C resonance signals for bond and free ligand. The chemical shift displacements induced by complex formation were ca. 24 p.p.m. to lower field for the carbonyl group signal, and about an order of magnitude less, to higher and lower field, for the other carbon signals. Doublets were observed for the signals of bond ligand with several members of both series, a feature which is best interpreted in terms of a slow exchange of the BF3 between the two sp2 orbitals of the carbonyl oxygen atom. Some evidence is presented for the much greater stability of only one of these cis-trans-isomers in four of the alkyl ketone cases.

ChemInform Abstract: AN IMPROVED METHOD FOR AROMATIC HYDROXYLATION WITH HETEROAROMATIC OXIDES

AbstractDie Belichtung des Pyridin‐N‐oxids (III) führt zu einem Gemisch′ aus dem Pyridon (I) und dem Pyrrol‐aldehyd (II).

A direct, low-temperature 1-H, 13-C, and 19-F nuclear magnetic resonance study of boron trifluoride complexes with stigmasterol, androstanolone, androsterone, testosterone, nortestosterone, androstenedione, and progesterone-1,2.

A direct, low-temperature 1-H, 13-C, and 19-F nuclear magnetic resonance study of boron trifluoride complexes with stigmasterol, androstanolone, androsterone, testosterone, nortestosterone, androstenedione, and progesterone-1,2.

Direct carbon-13 nuclear magnetic resonance study of boron trifluoride and boron trichloride complexes with ethers

A direct, low-temperature, 13C n.m.r. study of the boron trifluoride and boron trichloride complexes with several ethers has been completed. At ca.–100°, ligand exchange is slow enough to permit the observation of separate signals for bulk and co-ordinated ether molecules. The chemical shift changes induced by complex formation reflect inductive and steric effects. Doublet patterns were observed for the signals of co-ordinated ethyl s-butyl, ethyl t-butyl, and di-isopentyl ether. The most reasonable interpretation of this result appears to be hindered rotation about the O–R bond in the complex.

An improved method for aromatic hydroxylation with heteroaromatic oxides

Photolysis of the boron trifluoride complex of pyridine-N-oxide in benzene gives a higher yield of phenol than photolysis of pyridine-N-oxide alone; with some intramolecular models, intramolecular hydroxylation can be achieved.

Evaluation of Electrically Insulative Adhesives for Use in Hybrid Microcircuit Fabrication

Although it is generally accepted that the use of adhesives in the fabrication of hybrid microcircuits offers advantages over other bonding methods, there currently does not exist a set of guidelines for the selection of adhesives which will ensure sufficient compatibility with microcircuit components and metallization systems to meet the long use-life, high-reliability requirements of military and space applications. The initial results of a study directed to the task of selecting suitable evaluation tests which can form the basis for such guidelines for electrically insulative adhesives are presented. The properties of adhesives considered to be of major importance for the proposed application are enumerated and briefly commented on. Polymeric types of adhesives are briefly reviewed and the major epoxy resin-curing agent systems comprising the adhesives that are commercially available and represented as being specifically designed for microelectronic use are identified. Specific tests to determine the chemical and electrolytic corrosivity of adhesives to commonly used metallization systems, their long term outgassing after cure, and their bond strengths under a variety of conditions are defined and discussed in detail. Comparative results obtained to date from these tests are given for five representative adhesives. All are epoxies cured with a different major type of curing agent: a primary secondary amine, a tertiary amine, an anhydride, a modified heterocyclic amine, and a boron trifluoride complex.

Ultraviolet absorption studies and analytical applications of the ether complexes of boron trifluoride and phosporus pentafluoride

Ultraviolet absorption studies and analytical applications of the ether complexes of boron trifluoride and phosporus pentafluoride

ChemInform Abstract: A DIRECT (1)H AND (19)F NUCLEAR MAGNETIC RESONANCE STUDY OF BORON TRIFLUORIDE COMPLEXES WITH CYCLOALKANONES

Chemischer InformationsdienstVolume 4, Issue 40 Physical Organic Chemistry ChemInform Abstract: A DIRECT (1)H AND (19)F NUCLEAR MAGNETIC RESONANCE STUDY OF BORON TRIFLUORIDE COMPLEXES WITH CYCLOALKANONES A. FRATIELLO, A. FRATIELLOSearch for more papers by this authorG. A. VIDULICH, G. A. VIDULICHSearch for more papers by this authorY. CHOW, Y. CHOWSearch for more papers by this author A. FRATIELLO, A. FRATIELLOSearch for more papers by this authorG. A. VIDULICH, G. A. VIDULICHSearch for more papers by this authorY. CHOW, Y. CHOWSearch for more papers by this author First published: October 2, 1973 https://doi.org/10.1002/chin.197340099Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume4, Issue40October 2, 1973 RelatedInformation

A direct low temperature 1H and 19F nuclear magnetic resonance study of boron trifluoride complexes with 4-cholesten-3-one, 1(5beta)-androstene-3,17-dione, 5beta-androstane-3,17-dione, and obacunone.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDirect low temperature proton and fluorine-19 nuclear magnetic resonance study of boron trifluoride complexes with 4-chlolesten-3-one, 1(5.beta.)-androstene-3,17-dione, 5.beta.-androstane-3,17-dione and obacunoneRonald E. Schuster and Raymond D. BennettCite this: J. Org. Chem. 1973, 38, 16, 2904–2908Publication Date (Print):August 1, 1973Publication History Published online1 May 2002Published inissue 1 August 1973https://doi.org/10.1021/jo00956a037RIGHTS & PERMISSIONSArticle Views52Altmetric-Citations6LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (654 KB) Get e-Alerts Get e-Alerts