Nickel(II) hydride and fluoride pincer complexes and their reactivity with Lewis acids BX3 · L (X = H, L = thf; X = F, L = Et2O)

Reaction of the pincer hydride complex (tBuPCP)Ni(H) [tBuPCP = 2,6-C6H3(CH2PtBu2)2] with BH3·thf in THF at 190 K generates the corresponding borohydride complex (tBuPCP)Ni(BH4). The kinetically stable (but thermodynamically unstable) species undergoes reversible borane loss. The related fluoride complex (tBuPCP)Ni(F) shows the same reactivity towards BF3·Et2O, producing (tBuPCP)Ni(BF4) as the main final product. The processes were followed through multinuclear NMR spectroscopy and DFT calculations, at the M06//6-31+G(d,p) level of theory.