A Theoretical Study on the Mechanism of Boron Metathesis

De, Susmita and Parameswaran, Pattiyil and Jemmis, Eluvathingal D (2007) A Theoretical Study on the Mechanism of Boron Metathesis. In: Inorganic Chemistry, 46 (15). pp. 6091-6098.

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Abstract

The mechanism of the boron metathesis reaction of the transition-metal-aminoborylene complex $Cp(CO)_2FeBN- (CH_3)_2 + (8)$ with EX, where $EX=H_3PO (9ap)$, $H_3AsO (9bp), H_3PS (9aq), H_3AsS (9bq)$, $CH_3CHCH_2 (9cr), (NH_2)_2- CCH_2 (9dr), H_2CO (9ep)$, and $(NH_2)_2CO (9dp)$ is investigated at the B3LYP/LANL2DZ level. The analysis of bonding and charge distribution shows that the Fe-borylene complex (8) is a Fischer-type carbene analogue. The attack of the olefin takes place at the metal end of the M=C bond of the metal-carbene complex in olefin metathesis and proceeds via [2 + 2] cycloaddition, while in boron metathesis, the initial attack of the substrates takes place at the positively charged B atom of the Fe-borylene complex and forms the preferred acyclic intermediate. The energetics of boron metathesis is comparable to that of the olefin metathesis. Substrates that are polar and a have low-lying $\sigma^\ast$ molecular orbital (weak $\sigma$ bond) prefer the boron metathesis reaction. The relative stability of the metathesis products is controlled by the strength of the Fe-E and B-X bonds of the products 13 and 14, respectively. We have also investigated the possibility of a $\beta$-hydride-transfer reaction in the Fe-borylene complex.

Item Type:	Journal Article
Publication:	Inorganic Chemistry
Publisher:	American Chemical Society
Additional Information:	Copyright of this article belongs to American Chemical Society.
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	27 Sep 2007
Last Modified:	19 Sep 2010 04:39
URI:	http://eprints.iisc.ac.in/id/eprint/11957

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