Australian Journal of Chemistry Australian Journal of Chemistry Society
An international journal for chemical science

Carbene-Based Lewis Pairs for Hydrogen Activation

Jason W. Runyon A D , Oliver Steinhof A , H. V. Rasika Dias B C , Joseph C. Calabrese B , William J. Marshall B and Anthony J. Arduengo III A D

A Department of Chemistry, The University of Alabama, 3068 Shelby Hall, Tuscaloosa, AL 35487-0336, USA.

B Central Research and Development Department, E. I. du Pont de Nemours & Company, Experimental Station E500/1808, Wilmington, DE 19880-0500, USA.

C Current address: Department of Chemistry and Biochemistry, The University of Texas at Arlington, Arlington, TX 76019-0065, USA.

D Corresponding authors. Email:,

Australian Journal of Chemistry 64(8) 1165-1172
Submitted: 17 June 2011  Accepted: 22 June 2011   Published: 19 August 2011


A series of Lewis acid–base pairs containing sterically demanding carbenes were investigated for hydrogen activation that could potentially be reversible for use in hydrogen storage applications. When electron-rich boranes are employed as electrophiles, the imidazolium cation is reduced to a 2H-imidazoline (aminal). The aminals were synthesized independently by reduction of imidazolium cations with strong reducing agents. Carbocations were also found to act as electrophiles for hydrogen activation. Preliminary results revealed that it is possible to reduce an alcohol to an alkane using hydrogen gas as a reducing agent in these systems. Finally, it was demonstrated that a transition metal can be used as an electrophile to activate hydrogen through heterolytic cleavage.

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