Applications and reactivity trends of homoleptic p-block metal amido reagents
This review aims to develop an understanding of reactivity trends of p-block metal bases M(NR2)n (M = Sn: n = 2; M = Al, Ga, As, Sb: n = 3) towards organic substrates EHy containing one or more E–H bonds (E = B, N, P, S). These compounds not only act as good bases for the deprotonation of E–H bonds but recent advances in p-block amido chemistry have shown that, in addition, they can effect the dehydrogenic homo-coupling of primary phosphines and amines to give E–E bonded products. They have also been found to be active in stoichiometric and catalytic dehydrocoupling of amine-boranes, which has direct applications in hydrogen storage devices, revealing that these p-block catalysts offer potential alternatives to the extensive range of expensive and often highly toxic heavy metal catalysts. This perspective analyses three distinct reactivity patterns of p-block metal bases; deprotonation, stoichiometric dehydrocoupling and catalytic dehydrocoupling and attempts to rationalise reactivity in relation to the redox stability of the p-block metal.