Theoretical study of the activation of alkane C-H and C-C bonds by different transition metals

The activation of C-H and C-C bonds by different transition metal atoms has been studied using quantum chemical methods including electron correlation. The metals studied are iron, cobalt, nickel, rhodium, and palladium. A general result for all these metals is that the barrier for C-C insertion is...

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Bibliographic Details
Published in:Journal of the American Chemical Society 1991-01, Vol.113 (2), p.424-433
Main Authors: BLOMBERG, M. R. A, SIEGBAHN, P. E. M, NAGASHIMA, U, WENNERBERG, J
Format: Article
Language:English
Subjects:
400201 - Chemical & Physicochemical Properties
ALKANES
CHEMICAL ACTIVATION
Chemistry
COBALT
CORRELATIONS
DATA
ELECTRON CORRELATION
ELEMENTS
ETHANE
Exact sciences and technology
HYDROCARBONS
INFORMATION
INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY
IRON
Kinetics and mechanisms
METALS
NICKEL
NUMERICAL DATA
Organic chemistry
ORGANIC COMPOUNDS
PALLADIUM
PLATINUM METALS
Reactivity and mechanisms
RHODIUM
THEORETICAL DATA
TRANSITION ELEMENTS
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Summary:The activation of C-H and C-C bonds by different transition metal atoms has been studied using quantum chemical methods including electron correlation. The metals studied are iron, cobalt, nickel, rhodium, and palladium. A general result for all these metals is that the barrier for C-C insertion is found to be 14-20 kcal/mol higher than the barrier for C-H insertion. This can be explained by the difference in directionality between bonds to methyl groups and to hydrogen atoms. The size of the activation barrier is similar among transition metals in the same row but is considerably lower for the second-row metals than for the first-row metals studied here. This latter result follows from the more efficient sd-hybridization obtained for second-row metals, which in turn follows from the more similar size of the nd and (n + 1)s orbitals for these atoms. The differences in the atomic spectra between first- and second-row metals also play a part in making the barrier for second-row metals lower.
ISSN:0002-7863
1520-5126
DOI:10.1021/ja00002a007