Gas-phase study of Fe sup + -benzyne with alkanes

Journal Article · Wed Mar 29 04:00:00 EST 1989 · Journal of the American Chemical Society; (USA)

DOI:https://doi.org/10.1021/ja00189a003· OSTI ID:5296047

Huang, Yongqing; Freiser, B S ^[1]

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1. Purdue Univ., West Lafayette, IN (USA)

The unimolecular chemistry of Fe{sup +}-benzyne and its reactivity with small alkanes in the gas phase are studied by Fourier transform mass spectrometry (FTMS). Collision-induced dissociation of Fe{sup +}-benzyne yields benzyne loss exclusively. In contrast, photodissociation of Fe{sup +}-benzyne yields not only cleavage of benzyne from Fe{sup +}, but competitive loss of C{sub 2}H{sub 2} and C{sub 4}H{sub 2} as well. The Fe{sup +}-benzyne is formed from chlorobenzene by loss of HCl. This dehydrochlorination of chlorobenzene also occurs in secondary reactions up to six times forming products of the type Fe{sup +}-polyphenylene. Fe{sup +}-benzyne reacts with alkanes larger than methane to form a wide variety of product ions by mechanisms including hydrogenation and methanation of the benzyne ligand. All of the product ions can be explained by mechanisms based on Fe{sup +} insertion into either C-C or C-H bonds as the reaction-initiating step, followed by either alkyl or H migration from Fe{sup +} onto the benzyne ligand or, alternatively, by the migratory insertion of benzyne into a metal-carbon or metal-hydrogen bond. Photodissociation and ion-molecule reaction studies yield a value for the metal-ligand bond energy of D{degree} (Fe{sup +}-benzyne) = 76 {plus minus} 10 kcal/mol.

• DOE Contract Number: FG02-87ER13766
• OSTI ID: 5296047
• Journal Information: Journal of the American Chemical Society; (USA), Journal Name: Journal of the American Chemical Society; (USA) Vol. 111:7; ISSN 0002-7863; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400500 -- Photochemistry
ALKANES
AROMATICS
BINDING ENERGY
CATIONS
CHARGED PARTICLES
CHEMICAL BONDS
CHEMICAL REACTIONS
DATA
DECOMPOSITION
ENERGY
EXPERIMENTAL DATA
FLUIDS
FOURIER TRANSFORM SPECTROMETERS
GASES
HYDROCARBONS
INFORMATION
IONS
IRON COMPOUNDS
MASS SPECTROSCOPY
MEASURING INSTRUMENTS
NUMERICAL DATA
ORGANIC COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
SPECTROMETERS
SPECTROSCOPY
TRANSITION ELEMENT COMPOUNDS