σ-Borane Coordinated to Nickel(0) and Some Related Nickel(II) Trihydride Complexes

The reactions of the complexes [(dcype)NiH]2, 1, [(dippe)NiH]2, 2, and [(dtbpe)NiH]2, 3, with a
mixture of BEt3 and Super-Hydride (LiHBEt3) afforded σ-borane nickel(0) compounds of the type [(dcype)Ni(σ-HBEt2)], 4, [(dippe)Ni(σ-HBEt2)], 5, [(dtbpe)Ni(σ-HBEt2)], 6, respectively, with the concomitant formation
in each case of [(dcype)2Ni2(H)3][BEt4], 7, [(dippe)2Ni2(H)3][BEt4], 8 and [(dtbpe)2Ni2(H)3][BEt4], 9, respectively.
X-ray crystal structures are reported for 4 and 8.The reaction of BEt3 and LiHBEt3 was also reviewed in
detail.