Reversible hydrogen activation by a bulky haloborane based FLP system

Abstract

The FLP species bis(2-(TMP)phenyl)chloroborane (TMP = 2,2,6,6-tetramethylpiperidine)(1) was prepared and crystallized as a monomeric Frustrated Lewis Pair (FLP) displaying no apparent B–N interaction. Species 1 readily reacts with H₂ at room temperature to generate reversibly the zwitterionic H₂ activation product 2. Interestingly, in the presence of a base, 2 releases HCl, generating the novel FLP species 3 which is also monomeric.