OXIDATIVE ADDITION OF AMMONIUM AND IMINIUM TETRAPHENYLBORATES TO LOW-VALENT METAL-COMPLEXES - EVIDENCE OF SELECTIVE N-C AND N-H ACTIVATION - A NEW, EASY ROUTE TO CATIONIC ALLYLNICKEL AND HYDRIDONICKEL COMPLEXES
M. Aresta et al., OXIDATIVE ADDITION OF AMMONIUM AND IMINIUM TETRAPHENYLBORATES TO LOW-VALENT METAL-COMPLEXES - EVIDENCE OF SELECTIVE N-C AND N-H ACTIVATION - A NEW, EASY ROUTE TO CATIONIC ALLYLNICKEL AND HYDRIDONICKEL COMPLEXES, Organometallics, 16(5), 1997, pp. 834-841
The reaction of ammonium and iminium tetraphenylborate salts ((CH2=CHC
H2NH3)BPh(4), [(CH2=CHCH2)HN=CMe(2)]BPh(4), and [(PhCH(2))HN=CMe(2)]BP
h(4)) with transition-metal systems in a low oxidation state has been
investigated. We report the oxidative addition to (Cy(3)P)(2)Ni(eta(2)
-CO2) or (Cy(3)P)(2)Ni=NNi(PCy(3))(2) under mild conditions (253-293 K
) and describe a very selective N-C or N-H bond activation. (CH2=CHCH2
NH3)BPh(4) or [(CH2=CHCH2)HN=CMe(2)]BPh(4) react with (Cy(3)P)(2)Ni(et
a(2)-CO2) and (Cy(3)P)(2)NiN=NNi(PCy(3))(2) to afford the cationic pi-
allyl-Ni complexes [(eta(3)-C3H5)Ni(PCy(3))(NH3)]BPh(4) (1) and eta(3)
-C3H5)Ni(PCy(3))(eta(1)(N)-HN=CMe(2))]BPh(4) (2), respectively. The re
action of [(PhCH(2))HN=CMe(2)]BPh(4) with (Cy(3)P)(2)Ni=NNi(PCy(3))(2)
leads to the hydride-imino complex (H)Ni(PCy(3))(2)(eta(1)(N)-PhCH(2)
N=CMe(2))]BPh(4) (3) through N-H bond activation. Complexes 1-3 have b
een fully characterized in solution by NMR (H-1, C-13, P-31) spectrosc
opy The hydrido-imino complex 3, characterized in the solid state by a
X-ray diffraction study, shows a distorted-square-planar coordination
around the nickel atom with a very narrow P-Ni-P angle, 148.6(2)degre
es, involving the two P atoms from the traits PCy(3) ligands.