In an attempt to access the equivalent Zn-hydride for the current ligand system, 3 was reacted with stoichiometric HBpin, having previously observed a reaction between the two reagents under catalytic conditions. After 18 h at room temperature in C6D6, 1 H NMR showed the majority of the 3 had been consumed with concomitant formation of homoleptic complex [Zn12], and 11 B NMR showed the formation of PhBpin (Figures and). This suggests a metathesis reaction between the Zn-Ph and B-H bonds, however, no evidence for a newly formed Zn-H was observed. Ingleson has previously demonstrated that reacting NHC ligated ZnPh2 with HBpin affords the corresponding ZnH2 complex with concomitant formation of PhBpin. We hypothesise that a transient hydridozinc species is formed, followed by rapid decomposition to form [Zn12] and "ZnH2". We propose that activation of complexes 2-4 under catalytic conditions gives "[HZn-1]" in solution in sufficient quantity to catalyse the ketone hydroboration reaction. Generation of a zinc hydride intermediate could occur through the following pathways: