Aromatic Carbon-hydrogen Research Articles

Activation of aromatic carbon-hydrogen bonds of methyl-substituted benzenes by the palladium(II)acetate-diisobutyl sulphide system

Aromatic CH bond activation of various methyl-substituted benzenes by the Pd(MeCO 2) 2-SBu i 2 system have been studied. In the case of p-xylene the new and unusual compound [(SBu i 2)(2,5-Me 2C 6H 3)Pd(μ-MeCO 2) 2Pd(μ-MeCO 2) 2Pd(2,5-Me 2C 6H 3)(SBu i 2)] ( 1) has been isolated. Complex 1 reacts with styrene and carbon monoxide to afford ( E)-1-(2,5-dimethylphenyl)-2-phenylethene and 2,5-dimethylbenzene carboxylic acid, respectively. It has also been found that coupling products, biaryls, are formed in the reaction between Pd(MeCO 2) 2-SBu i 2 and methyl-substituted benzenes. The isolated arylpalladium(II) complexes and the coupling products have been characterized and identified by means of 1H NMR, GC-MS, and elemental analysis. On the basis of the isomer distribution of both isolated arylpalladium(II) complexes and the coupling products, the effect of the methyl groups on the benzene nucleus towards aromatic CH bond activation is discussed.

Characterization of asphaltenes from Cold Lake heavy oil: variations in chemical structure and composition with molecular size

Asphaltenes from Cold Lake oil were separated into fractions by size exclusion chromatography to study the molecular size dependence of chemical structural characteristics. Each fraction was analyzed by proton NMR and UV–visible spectroscopy and by elemental analyses for C, H, N, S, Ni, and V. The results indicated that the nature of the average chemical structures in Cold Lake asphaltenes were not uniform throughout the total range of molecular sizes but varied significantly; some changed gradually and some changed quite abruptly. Especially in the very low molecular-weight fraction, the size of aromatic moieties seems to be much smaller, the contents of both aromatic carbon and aromatic hydrogen are higher, the C/H ratio is higher, and the porphyrin and vanadium concentrations are much higher than in heavier fractions. Keywords: Cold Lake asphaltenes, size fractionation, vanadium, proton NMR, porphyrin, chemical structural analysis.

Preparation of 3-acetyl-2-hydroxyindoles via rhodium carbenoid aromatic carbon-hydrogen insertion

Synthese du compose du titre par reaction des α-diazo anilides appropries avec Rh 2 OAc 4 dans du benzene a reflux

Iridium(I) insertion into an aromatic carbon-hydrogen bond. Synthesis and structure of [Ir(H)(CO)(bq)(PPh3)2]PF6 (bq = 7,8-benzoquinolinato)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTIridium(I) insertion into an aromatic carbon-hydrogen bond. Synthesis and structure of [Ir(H)(CO)(bq)(PPh3)2]PF6 (bq = 7,8-benzoquinolinato)Francesco Neve, Mauro Ghedini, Antonio Tiripicchio, and Franco UgozzoliCite this: Inorg. Chem. 1989, 28, 15, 3084–3086Publication Date (Print):July 1, 1989Publication History Published online1 May 2002Published inissue 1 July 1989https://doi.org/10.1021/ic00314a046RIGHTS & PERMISSIONSArticle Views70Altmetric-Citations15LEARN 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 (336 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

Reaction of dialkylamido and alkylimido derivatives of molybdenum and tungsten with o-arylphenols: intramolecular activation of aromatic carbon-hydrogen bonds by Mo-NR2 groups

Reaction of dialkylamido and alkylimido derivatives of molybdenum and tungsten with o-arylphenols: intramolecular activation of aromatic carbon-hydrogen bonds by Mo-NR2 groups

Intramolecular activation of aliphatic and aromatic carbon-hydrogen bonds by tantalum(III) metal centers: synthesis and structure of the bis-metalated compounds Ta(OC6H3ButCMe2Ch2)2Cl and Ta(OC6H3PhC6H4)2(OAr-2,6-PH2) (OAr-2,6-Ph2 = 2,6-diphenylphenoxide)

Intramolecular activation of aliphatic and aromatic carbon-hydrogen bonds by tantalum(III) metal centers: synthesis and structure of the bis-metalated compounds Ta(OC6H3ButCMe2Ch2)2Cl and Ta(OC6H3PhC6H4)2(OAr-2,6-PH2) (OAr-2,6-Ph2 = 2,6-diphenylphenoxide)

Dissolution of peat in simulated recycle solvents

Dissolution of peat in simulated recycle solvents has been studied at 420 °C for 15 min. The contents of tetralin, naphthalene and p-cresol in the solvent were varied in a factorial design. The composition of the simulated recycle solvent at the central point in the experimental design simulated the content of oxygen, aromatic carbon and donatable hydrogen obtained for a hydrotreated peat-derived liquid. The results were interpreted according to the hypothesis that the intermediate residue after CO 2 evolution undergoes dissolution reactions in a coal-like manner. The degree of dissolution was found to depend on solvent aromaticity and content of hydrogen-donor. p-Cresol influences the degree of dissolution only as an aromatic component of the solvent. The amount of hydrogen donated was found to decrease for highly aromatic solvents. The interpretation of this is that the more aromatic solvents shuttle hydrogen from peat more rapidly than direct H-transfer from tetralin.

Activation of Aromatic Carbon–Hydrogen Bonds by Palladium(II) Acetate–Dialkyl Sulfide Systems. Formation and Characterization of Novel Diphenyltripalladium(II) Complexes

Abstract Palladium(II) acetate reacts with benzene in the presence of dialkyl sulfides at 70 °C to afford novel diphenyltripalladium(II) complexes of [(R1SR2)PhPd(μ-MeCO2)2Pd(μ-MeCO2)2PdPh(R1SR2)] (1a; R1=But, R2=CH2But: 1b; R1=R2=Bui: 1c; R1=R2=Pri: 1d; R1=R2=Et). Adducts, [Pd(MeCO2)2(ButSCH2But)2] and [Pd(MeCO2)2(SPri2)2], prepared by the reactions of palladium(II) acetate and the corresponding dialkyl sulfides in benzene at 5–10 °C, change to 1a and 1c, respectively, on heating in benzene at 70 °C. In contrast, reactions of palladium(II) acetate with toluene or thiophene in the presence of diisopropyl sulfide afford no isolable tolyl-or thienyl-palladium species, but coupling products, i.e. bitolyls or bithienyls, are detected by GLC analysis. Treatment of 1b with styrene produces trans-stilbene, whereas 1c reacts with carbon monoxide as well as carbon dioxide to yield benzoic acid. When palladium(II) acetate and t-butyl phenethyl sulfide are heated at 80 °C in benzene, an adduct [Pd(MeCO2)2(ButSCH2CH2Ph)2] is formed, in sharp contrast with the case of benzyl t-butyl sulfide, which gives a cyclopalladated complex under the same reaction conditions.

Cyclophanes. V. Synthesis and conformational analysis of novel heterocyclophanes containing 2,5-bis(5-oxazolyl)furan units.

Two novel heterocyclophanes, dioxazolo[32](2, 5)furanometacyclophane (5) and the higher homolog (6) possessing 2, 5-bis(5-oxazolyl)furan units, were synthesized by the one-pot coupling reaction of 1, 3-bis(2-isocyano-2-tosylethyl)benzene (3) with furan-2, 5-dicarbaldehyde (4). On the basis of the variable-temperature nuclear magnetic resonance (VT-NMR) spectra of 5, the conformations in solution both at room temperature and at -18°C could be assigned as a syn form, and the energy barrier (ΔG〓) for the conformational flipping at the coalescence temperature (Tc=12°C) was determined to be 58.0 kJ/mol, which is lower than that of dioxazolo[32]metacyclophane (1a). Therefore, it was suggested that the oxygen atom of 5 with its lone pair is less bulky with respect to the conformational change than the aromatic carbon-hydrogen bond of 1a.

Aliphatic versus aromatic carbon-hydrogen activation and the x-ray crystal structure of [IrH(H2O)(7,8-benzoquinolinato)(PPh3)2]SbF6

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAliphatic versus aromatic carbon-hydrogen activation and the x-ray crystal structure of [IrH(H2O)(7,8-benzoquinolinato)(PPh3)2]SbF6Maryellen Lavin, Elizabeth M. Holt, and Robert H. CrabtreeCite this: Organometallics 1989, 8, 1, 99–104Publication Date (Print):January 1, 1989Publication History Published online1 May 2002Published inissue 1 January 1989https://doi.org/10.1021/om00103a013RIGHTS & PERMISSIONSArticle Views334Altmetric-Citations56LEARN 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 (672 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

ChemInform Abstract: Aromatic Carbon-Hydrogen Bond Activation. Novel Synthesis of 1-Naphthol Derivatives by Palladium Catalyzed Cyclocarbonylation of Cinnamyl Compounds.

The cinnamyl derivatives (I) react with carbon monoxide (II) and acetic anhydride (III) in the presence of a palladium catalyst to produce the acetoxynaphthalenes (IV).

The catalytic activation and functionalization of carbon-hydrogen bonds. Aldimine formation by the insertion of isonitriles into aromatic carbon-hydrogen bonds

Many examples of the activation of aromatic and aliphatic carbon-hydrogen bonds by homogeneous transition-metal complexes have appeared over the past few years, offering attractive new routes to organometallic species. While several of these reports involve oxidative addition of low valent metal complexes to alkanes or arenes, these new adducts have not proven to be useful for the generation of functionalized hydrocarbon products. Reports of successful metal-based alkane functionalization include free radical oxidations, intramolecular cyclizations of alkyl carbenoid species to given cyclopentanones, aromatic isonitrile insertion to give indoles, and alkane dehydrogenation to produce olefins. Arene functionalization reactions commonly depend upon the presence of tethering groups, although the production of benzaldehyde, benzoic acid, styrene, and phenylsiloxane insertion products have been recently reported. They report here a new type of iron catalyzed insertion of isonitrile into the C-H bond of arenes to produce aldimines (eq 1). RNC + C/sub 6/H/sub 6/ (Fe) ..-->.. ..delta..G/sup 0/ approx. = -11 Kcal/mol C/sub 6/H/sub 5/ - CH = NR (1).

Aromatic carbon–hydrogen bond activation. Novel synthesis of 1-naphthol derivatives by palladium catalysed cyclocarbonylation of cinnamyl compounds

Palladium catalysed cyclocarbonylation of cinnamyl compounds gives 1-naphthol derivatives in good yields whereas the similar carbonylation of trans-β-bromostyrene yields a polymer containing benzindanone units.

Photoinduced oxidative addition of a distal aromatic carbon-hydrogen bond of a benzyl group. Isolation and characterization of [cyclic]-(.eta.5-C5R4CH2C6H4)Fe(CO)2 from irradiation of (.eta.5-C5R4CH2C6H5)Fe(CO)2Me

Photoinduced oxidative addition of a distal aromatic carbon-hydrogen bond of a benzyl group. Isolation and characterization of [cyclic]-(.eta.5-C5R4CH2C6H4)Fe(CO)2 from irradiation of (.eta.5-C5R4CH2C6H5)Fe(CO)2Me

A .eta.2-arene complex of rhenium: synthesis, characterization, and activation of the aromatic carbon-hydrogen bonds

A .eta.2-arene complex of rhenium: synthesis, characterization, and activation of the aromatic carbon-hydrogen bonds

Photogeneration of reactive [ReH(diphos)2]. Its reversible coordination of carbon dioxide and activation of aromatic carbon-hydrogen bonds

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotogeneration of reactive [ReH(diphos)2]. Its reversible coordination of carbon dioxide and activation of aromatic carbon-hydrogen bondsMark G. Bradley, David A. Roberts, and Gregory L. GeoffroyCite this: J. Am. Chem. Soc. 1981, 103, 2, 379–384Publication Date (Print):January 1, 1981Publication History Published online1 May 2002Published inissue 1 January 1981https://doi.org/10.1021/ja00392a023RIGHTS & PERMISSIONSArticle Views180Altmetric-Citations54LEARN 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 (757 KB) Get e-Alerts Get e-Alerts