A Density Functional Study Of
Catalytic Boration Processes Involving Ethylene By Rh(I) Complexes
Christoph Widauer,a Rochus
Schmid,b Hansjörg Grützmacher*,a
and Tom Ziegler*,b
Contribution from the aDepartment
of Inorganic Chemistry, ETH Zürich, Universitätsstrasse 6, CH-8092
Zürich, Switzerland and b
Department of Chemistry, University of
Calgary, 2500 University Drive N. W., T2N 1N4 Calgary, Alberta, Canada
We present an investigation on the associative and dissociative
pathways of the rhodium(I)-catalyzed olefin boration reactions, RhCl(PH3)2
+ XB(OH)2 + C2H4 Æ
RhCl(PH3)2 + XC2H4B(OH)2
(X = H, TeH), by means of first principle density functional theory (DFT)
type calculations. The boration reaction is found to be exothermic by 31kcal
mol-1 for X = H and 13 kcal mol-1 for X = TeH, respectively.
For both generic model systems, the most favorable mechanism is associative.
After initial oxidative addition of theX-B bond to the metal center and
coordination of ethylene to the complex,B(OH)2 migration is
preferred to X migration. The catalytic cycles are completed by reductive
elimination which is calculated to be the rate determing step.