Alkali Metal Species in the Reversible Activation of H 2

MP( t Bu) 2 (M=Li, Na, K), KH and KN(SiMe 3 ) 2 are shown to activate HD reversibly. In the case of MP( t Bu) 2 this leads to isotopic scrambling and the formation of H 2 , D 2 , H(D)P( t Bu) 2 and MH(D) in C 6 D 6 . In toluene, KP( t Bu) 2 reacts with H 2 but also leads to isotopic scrambling into the methyl groups of the solvent toluene. DFT calculations reveal that these systems effect H 2 activation via cooperative interactions with the Lewis acidic alkali metal and the basic phosphorus, carbanion, or hydride centres, mimicking frustrated Lewis pair (FLP) behaviour.